University of Ghana http://ugspace.ug.edu.gh UNIVERSITY OF GHANA, LEGON GENOTYPE BY ENVIRONMENT INTERACTION EFFECT ON BETA-CAROTENE AND SOME YIELD COMPONENTS OF YELLOW ROOT CASSAVA (Manihot esculenta Crantz) GENOTYPES IN GHANA BY NORBERT GODONOU MAROYA A DOCTOR AL THESIS SUBMITTED TO THE DEPARTMENT OF BOTANY, FACULT V OF SCIENCE, UNIVERSITY OF GHANA, LEGON, IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHYLOSOPHY (Ph.D.) IN BOTANY. .JUNE,2008 University of Ghana http://ugspace.ug.edu.gh DEDICATION I dedtc&te mlS work to my beloved wife Calberioe Edith and children Kenneth. Gwladys. Joel md Mcrveillc They should never fOfiet thai: bard work.. pers£SCence, courage., and plrience are kcysoflUCCCss in this world University of Ghana http://ugspace.ug.edu.gh DECLARATION I hcreby dcclare that this thesis is the result of my own original rnearch and thai oorar1 of 11 has been presented ror another degree in this University or el5ewheft - f-~- - -=:::::.\). ......... ,. .. :::. ..... . .~.?2."""'"'~~ ~orNr1 Godouo. MAROYA Date Student . ' ,I. ·· ............ · ~ ............ :':::'~:YW. ... .. PrO'"$or E lUrnlu5 LA) Supervisor _ /~ /: . Oale University of Ghana http://ugspace.ug.edu.gh ACKNOWLEDGEMENTS Firsc, I would like to Cllpres,5 my sincere gratitude. and thanks to Prof. I. K ASANTE for guidiDt roe through this study. I wish to acknowledsc his cornpuly and suppon durins the dataooUccflonbothattbe field and laboratory I amalsopeful for his cheerful and palienl SUperv1SKm during tbe final prep&nlIion of this disscttation I am also C1C1:remel y thankful to Profes~r Emeritus E LAING for the supervisory role he played in bringing me this far HIs professional and technical advice to me is wonhy to be I am also Indebted to Dr A. G O. DIXON for initiating Ihis programme through Prof I. K ASANTE The financial suppa" for this work from the International Institute of Tropical Agricutture Harvell Plus Chalknlllc Pru~ramme through Dr, A. G 0 DIXON is highly I am aJlO ptful to the Staff of the Department of Botany forlhclT suppon I \NO.dd also M;c to thank tbe Staff of the following InstitutIOn. for provision of experiment.' plocsandiabour (i) Wench. Agricultural Station Ministry of Food and Agriculture (MOFA). specially MT E BOAMPONG Plam Gmctic Resourca Research Instil ute, Bunso. Council for Scienllflc and lu..stnaI Research(CSI'R) PokuaM: Research SI.Uun ufCrops Re~ Insr:ituIC. ('S IR University of Ghana http://ugspace.ug.edu.gh I wish to aclloo", ledge the usist.tnce from lhe Had,Depanment of Nutrition. Noguchi "-1emonal lnstitute for Medical Research (SMIMR). Legon. for the ptOY1sion of labonllory ..t-the laboJ>lout Wood .7 control FleiddatacolledKm 47 ~ScoreRAting 47 _.ScoreRaing Numwo(pllntshan,'tiledperhectart Perctntagto(planl standi at harvest Number o(saon~(' mol, per plant f\umbero(Slora~('rootsperhec1are Freshstorage roolwe1shtpcrplanl J JJ8 fresh ....... rootyieldpechcctare(tlltaj AVUlSe stor. root weight per root (8) J 3 J 10 Fmh shoot ",eight pet plant (kS) jO FreshIhootYlddpcrhccwe(tIha, Harvest index 51 Sit. ... root dry maher c:onIent (%) 51 Or) ,""'wright perplanl(kg) 51 Dr)' root } Icld per hccwe (tIha) 52 RcucarulenedatacollCC1ion Samphnl and sample prepllUlll0n ~2 EXltaCUon PetrukumcthrfIPf-:JPhase Concentralt~ln III evaporalionof ••l lh ... nt University of Ghana http://ugspace.ug.edu.gh 54 ll5 o.u. ana1ysi~ 54 J ) ~ I Vana.ncc componc'l'll!O 55 Broadsensehentabllit) 55 ll5l pbenotypic coefficient orVarialion 55 1354 Cienot)'P,cCuc:fficienlofVanatioa RESULTS Sproutmg at IWO weeks after planting 56 NumberofplantshatvescedperhecCare 56 57 Numberofsaoraaerootlperbectate Awnp number of stOBge roots pc1" plant 62 Fresh stonge roots yield pet' hedare (tIha) .7 fresh stOl'l8e rnots weight per plane (q) AYCI'&8emshstor18erootwe;!lht(tz) F~hlop~t"'etghtperhoc1are(tIha) hnh!ohooilW'CISncpcrpianl(ks) Hanhllndn. \tellmess 412 PereentattedrymahercontentofllOnBCrooI(°I.) SlOn8e root drv yield pt!f hectare (tIhI) Storagcrootdr)\olI(',gtwpcrplint(kg) 17 BdII-c.aroceneooncentrarloolnfrabllOnfp:roCIt(JAWI) 92 4.16 8eu.~tenecontemperfreshIJlOl'llJCrooI(m!l' OJ Heta-ca,ottncconlcntinstorlgcrootspcr planl(mS) fkt.-UJ."tntcontcn\I"Allrafterootsperhccqre(&) University of Ghana http://ugspace.ug.edu.gh Winning genotype::t and megafl in fresh $lense root: (...wg) fktl-carotene content pefSloragerooc (mg) 107 B 7: I ABLE 18 r\\tMII,.etaCtion aoU)'SI1 of variance lI'Ic1uchng the first tOut Interaction PCA uea for the: stoqge root WClght p¢f plan! of niM yellow root and one \\T11e root CI.SM\l1 gttlOt)"pes lested in 10 environments 12 I ABU: 19 A\lerage fresh storage root ..' tight nine yello,," rOOl And one wnte TOOl ~ aaocypet ia 10 environments_- TABLE 20 Proportion of sum of ~uarn for maIM effec1!o and imeractlon fm a\-na~e weIght of individual fresh storage mol for nlnr yellow roOl: and one .... Tile rOOl cassava genotypes In 10 environmenu 7' TABLE 21 A\etagt fresh shoot.....a,m ia 10m per hrct,IJe fOf nine :~I~:n:~t:nd ~ write root c.uY\1 ge",ll}f'n In 10 TABU 22 PrnportlOn (If ~m of !oQU&rcs fOf maIO effects .oct u'l(factHlnfur.\ttagc:freshshoolyieldperh~for University of Ghana http://ugspace.ug.edu.gh rune yellow mol Iftd one wnle root cusaVl genotypes 71 In 10 CI1\1lronments • I ABI.E 2l A_ frnII_ wash< perp!ul!k8) for ..... yellow root and one write root CUKW genotypeS In 10 TABLE 24: Propof1ton of ~ of squares for main effects and iG&erIction lOr averqe fresh shoot weight per pIarW for IIinc yellow root and one write root ca.ava geootypes in IOcn"uonments - 79 I ABl.E 25 Harvest index for nine yellow root and one wrire rool CU$I.\la gtnOl)'PfS in 10 eevironmeal5 30 TABLE 2() Proporuon of sum of Iquarcs for main effects and Interacuon for harvest index for nine yeUow rOOl and ooe write root CUllava genof)'Pe5 in 10 environments- TABLE 21 Avtft8t mealiness score for nine yellow root Md one ......u1'OOC~va~inIOenvitonmcals - TABLE 21, Proportion of IWII of squares (Of main effect, and interaction for mealiness score for ninc yellow ~ .nd oncwme root CUS8\1agen0fype5 in IOcnvironmcnh- 84 I -,\Ul.E 29 Avenge Pa'otntagc of dry matter content in Ito,.. root (-/.) for mne yenow foot and one write rOOl c:usava lJICI'OfYPCSia IOenvtronmentJ 8S TABLE }O Proportion of kim of squarn lill main effect~ and i,.cnctioD for dry rnancr content \0 Sloragc root for :~r=,rnoIandonewrrleroot8eno1ypesinIO 86 I A.BIl: ,\ I -'\ \tVU Imeraction analysis of "'ariance Including the fitsr ft\ur ImUKt;o., peA axes for the Pefcmtaac of the sI01age 1'00( dry InIher COf nine yellow root and one wrue root CUll:VI genotypes Ie.led in lO enVlfonments TABLE. 12 A~ dry yield of S10rage fOOtS per hectare (l/ha) for ~neyel~tOCMandonewriterooteassavalJenotypes tTl IOarvtronments I \lil I. ;3 Proportion of Slm of sqUAreS fOf main effectl and ul1eractKwl for stonge root dry yidel in tOM per hectare (Of nine ycetlow root and one...me rOOl CAStaVI ~~"ohpes in 10 envuon~ms University of Ghana http://ugspace.ug.edu.gh rllne yellow fOOl and one write root CUSlVI genofypeS n In 10environmenu - T ABtE 23 Awn. tieIb sbooI waght per plant (kg) for Gille yellow rooc and one write root ca5ilva genotypeS in 10 78 TABLE 24: Proportion of sum of squareI ror 'Nlln effects and iaMnctioa for .venae fresh shoot weight per plan'l ror lliMyellowrootandonewriterootcassaVl~ in IOmvironmenll - 79 r ABLE 25 Harvest index ror nine ydSow root and one write root CU6I\'a gcnoI)'pes in 10 erlvironment1, rARLE 26 Proportion of sum of squares for mam effects and interaction for iwve51 index for nine yellow root and one write rootcass.a .... genorypes in 10 environments· 81 TABLE 17 AVCf'age mealine:s. ~ for nine yellow root and one \\Tlte1'QdcuavasenotYJ)eSinIOenvironmeots, - 1-\B1.l:. .:!!I Proportion U5UIII of squares ror main effects and Inleractlon rotlnellinesl ICOre for nine yellow rooc and one wrne rOOl eaua\'a genotypes in 10 enYiroomenll- I .o\tJl.f. 29 Averqe Percentage 0( dry matter content in st0f'&8e root C-/.) for nine yeilow root and one write rOOC CU5lVI gmocypresia lOeiMroa:mt'nls, .10 Propofuon of sum of squar~ for main effects and InlcnttOt fOi dry matter contenl in IIOrQe rooc for :':r:''':::',1'001 and one Mlte rOOl genotypes m 10 1 AUll, \1 A.\t\o1 llnteractionanalysisofvariance intludingtht tint fnur interaction PCA axes for the pen:entaae of the loIUraserootdry rrlIherfor nine yellow fOOt and Ol'k' \...,l1e root calM. ... senotypcs lested in 10 environments 'A.BU. 12 AvefI8e dry yield of storage rool!. per hectare (tI'ha) for niftCyellowfOOllnd one \\Tile root cassava genotypes Inl0eavifOftlhCnts TABLE JJ Proportion of !Urn 0( square" for main dfea.s and 'nter~ion for 1lOQ8C roue dr) )Icld In tom per hectare for nine yelSO"" rooc and t~ wntc rooc cassa .... ~ypain'Oen\·lrnnmC'n" University of Ghana http://ugspace.ug.edu.gh TABLE 34: Average storage root dry weisht per plant CkI) for, ruM )'cUOw rOOl and one write root c:usava genotypeS III 10 ~~~~ ~ TABLE lS: Proporboa of ...., or squares fur main _ and ~fur __ drywoightpcrplantfur"'" yelkrwrooc and one write root C&$S&VI Senorypes In 10 ecYironments ~ TABLE36, Avtra8eb~~lnfreshstora.scrOOt t""lI ror "",,,,ydlow_ casoavO I"""'YJ><'",IO eaviromDeDtl ~ TABLE 37 Proportion of !'.Um of squares for main effects and ialtnctlOl'l for .... ct1II'8 beta CIJOMae concentrllion in h5h stonge root fOr I8YeIl yellow root c.auava KenofypeslnlOmwonlllCllls r ABLE ,lK AMMI analysis of variance Including the first four Inleractions PCA axes for beta c:arotenc concentration (..,100g) for teVCIl )'CHow root cassava genotypes ldCId an 10 ~Yiroameau TABLE }9, Awnee beta carotene content in indi",dual fresh stor. root for teYtn yellow rOOII cauaVi genotypes in 10 et\\lronments 96 r ABLE 40 PropoftlOfl of !UIn of squares for maUl cffcds and ImerlClton for lYCra8C beta carotene content in Indl\ tduaJ ftuh stOl'alJC root for seven yeUow root e..,,\0011"" scnotYPCS in 10 environments TABLE 41 AMMI oInaJrsil of .. ..-i.nee includirw the firn rour Imt'l'ac1luns PeA u.n for bcu c.anxene content per stongt mot ('"I) for K'VCO yellow root c:asava SCOO1ypes tested in 10 environments r ABLE 42, Avu18t beta carotene in fresh storage roots per plant (rna) for seven yellow root euaava 8enotypes ia 10 environments r ABLE 43 Proportion of Sum of Squares for main effectl and IntCTKttonfor ...~ bctacarotC1"ltcontentinffesh IotO,.. root per plant of 5C'\Vl genotypes in 10 C'm Irunments In GhaaI tOO TABLE 44 A\t\11 "nalnis of ,·anana; inc;ludlfl8 lbr fim fnur ImtT'aCttons PC' A Des for bet" carotC'f'lC conlmt per plant (~) of sc"-:en ycllow-flnhed "('lltlt'JX'~ Intcd In IOcnVU'onrnentslnGhana - - 100 University of Ghana http://ugspace.ug.edu.gh TABLE 45 Awrqe: bda carotene conlent in freJh 1t0J'l8C root per hec1arc for KVen yellow root CASSava genorypn in 10 environments 102 IABI.f. 46' Proporuon 01 Sum of SquIreI for main effects Iftd InteractlOll for avet'l{l:e beta carotene eomcnt in frc~ slorage moe per hect~ ofsevcn genotypes ia 10 cnvironmems In Ghana 10] TABLE 47' AMMI aoaJysis of vanance mclud.irl@ the m. four lmCf"adioni PCA u.es for beta carotene oorCcnl per hccwc (,,) of leVeR ydlow-flcshed genotypeS teskd in 10 erl\lronments in Gh4na 10] I ABLE 48 GenotypIC variance (Q82), enVironmental variance (ac2), ~enotype by environment imeraction variance (0p2~ pbenotypic vananc< (op2). brood ...... heritability (h2); phenotypic coefficient of variation (PCV) and aenot)'pic coefficient of variation or traits In teYeIl ydlow cauava genotypes les:led in 10 enVironmtnts In Ghana 118 1 ABU:. 4Q Pearson product-moment correlatiON arnol1@ bna carotene traJ1s and agronomic variables for seven yellow rOOI cassa. ... !lenotypes tesled in 10 CllVIl"ODIDtnts In Ghana Pearson product-moment conclatlons among AponomicITaJlS University of Ghana http://ugspace.ug.edu.gh LIST DES FIGURES PQ< ~onthly ralflfall III Wench AgriC. Station &om July 2004 10 40 July 2007 FIB- 2 MoIO)y raindays at Wenchi Allnc. Station from July 2004 10 luly2007 hg) Monthly rainfall .. 8UMO from July 2005 10 Jooe 2001 42 ~ It( 4 Monthly raUl dIyIlt BURIO from July 200S to June 2007 42 Fig ~ MOOlhly rainfall at Pokuase dunng the cropping season 2~ 2007 Fig b Montbiy rain da" ~ .t Pokuase dwing croppmg season 2006-2007 Fig 1 Mean perionh.lrKe and liability of SC:H~n ydlO\~ fOOl c.ass.av. senorypellnl0ennronmentsforbctae&rOtcnec;o~ndion infrnhSlOf'I8C rooc f-188 Mq&I~n'lfonmmc defined by different winning leYen yellow runt CH5olI\. ~enoty~ Inted in 10 environmenti for the beta CAlOileneconccnu.llon InSCora,serooi 106 flK q Man performance and -.ability cisevcn yellow rooc CU!>ava ~~ In 10 C1wtrOOmeniS b' bC'ta carotene content per """'8<- hK 10 Mep-environment defined by ditTereru winmng seven yellow I"OIX awa .... genOlvpes telled in 10 cnvironmencl (or the beta caroIcnecontentpe15t"oragtroot Fig. 11 Mean p«formanct' and ~Iabllil\' of SC'\en l,rdlo\\, tOOl CU5l,,' senorypresinlOen\uonmcntsforbetacarOCencconlenlin SlOf'18Itroolperpb.m. Fig. 12- Mega. .e 1wironment defined by different winning !ot'\C'n }'~n" .... root easy\ .. ~enC'ltypes lCS1ed in 10 cnvironrm-nt!l. for thl' ''''''1.1 c.olCfleconlenrm'OtoragcfOOlperpiant 112 ht( 1J Mean performance and !Ubili1~ of IIeWa yellow I'OOC cusa .... genocypn In 10 cn\lronmc:ms for beta talO1ene comen! III UOf'I.4JCroohP<'fh«lve University of Ghana http://ugspace.ug.edu.gh F;" I": ~vironrnent defined by difrereDt winnin8 Jeven yeUow root CUMva genotypes tested in 10 fIIVlronmeotl tor lhe beta CItOtaICoontentinstoq,gerootpcrhec'lare liS University of Ghana http://ugspace.ug.edu.gh List of Abb,.viation and Symbols ACMV: Africaa cassava mosaic virus AMMJ: Add111vt: main cffect aDd multiplicative interaction UAT: IniemwonaJ Centre of Tropical Agriculture CGIAR: Consutwive Group on lnternallonal Agricuttwal Research CRI:CropsR.esearc.hlnslituIC (.'ORAF: (\)C\)rtll aue. CIt Cmlre Africain pour Ia Ru:herche et Ie (U\("A:CoIlaborativeStudvofCassaYa cv: Cocffic:ienr ofVanauon DFlD: I:kp4nmcnt (or InlcrnauorW Development .. -\()STAT: I 'n,ted 'alK)fl Food and Agncuhure OrganlUIKm Statistics I, ,""""YP< G • E: GenoI)"PC by Ennronment Interaction .. ': Uentabilt1yBroadScn),C University of Ghana http://ugspace.ug.edu.gh UTA: lrocmll."w InsrituteofTropicaI AgnculiurC' nrRllmcrnalionaiFoodpoitcyResearchlnstilutC' lPCA Interaction pnncipaJ components axis 1~"'iD: Leut iqUlificanl difference "lAP: ~onthal\erplanling ~&E:Monitoringandl::::valu.arion MOtA. Minisuy Of Food IIId AsricultweofGhana l\'IS:~ean !i.quare PCl: Frnl ponc.pal compontllt .1'''\ Pcl: Second pnncipaJ compontnt axn P( "\': Phenotypic coefficienr: ofvariauun P[: Pwoleum Elher t :("(" In'\C'nIlyofCapeCout \\ ECARO WCSl and Central Afncan Council for Agricultural Research and G.l:' II \ , ron~n ..l vanance G.·: Gcnocypebyttl\.ron~nt,"'C"ra("1rlln \ ... ;ann: o/P~not)"pic\'anancc University of Ghana http://ugspace.ug.edu.gh ABSTRACT , .' ..... I.andonc ",hllCroot cas!'I.J\'" ~Cn{ll~rc) 'Acre evaluated in ten environments In m;JbllllyandhentablhlyO(lhcuagronomlctratlslndbetaCatOltnCconrenlln \ ,J .... IU locntlfy ca.. . SO),-a genotypes thaI combine high rOOI yu:td, high dry maner Jflll~'m' .... unll·nl U\ 'l(lfa~( root Such ctiSa\oa genotypeS can be used 10 combat . ,l', •. 1 \It,lnlmA JClklcncy for children underthe.ge ofr.\-c and forpn:gnant and 1)11" ,Iudv .... Iarted In 20(),4 al Wench. Agncullural stalioR with. pn:limmar') "I I · II~ , 111 1"1-,01 1442; 01,'1610: 01 1663 were ~clcctcd from the: first year c'penmenl b"'l·.! \lfl their mol yu:ld and the deer )clloWlsh colour of their rool ncsh . In 1005 two ," prrHtll'!H,\o\crCl"Unductcdal \\'CIIChllnlhcFo!'t'<;t·Sa\"annahTransltlon.loncandal Bun~ Ih' 11\', , ... ere 01 · 1361<. 01 1M.' and 01 / 1412. for the beta carotene chara..:len,lh::- Ihen= .lresl~lfiean'dlffercncesbefwecngcnotypcs rorbctaellrotenecontentperrool, bcla..:arolcne .;Cd on Ihe "hmc results the yellow rOOl cassava ;·o.:rhll~f'I." III I.lb~ and 0111417 which coml"tmed high fresh storage rOOI )'Icld, high dry root ,,,I,, \\1111 hl~h tlc:lacarolcncconlcnlm " .. r;l~c root can be proflO,,-" (II the (lUlermosllayer which is the periderm, is composed mostly ofdad cork University of Ghana http://ugspace.ug.edu.gh cells wbicheffectively sea1 the surface of the tuber, (ii) a thin conex, which is usually white, but may be IIRged pink, yellowish or brown., (iii) a core or pith consisting mainly ofparenchymtwhicbisrichinstarch Cassava plllId grows u a ihrub, with the stem reaching heights of up to 4 m and a d1&Jllder of about 2 U) 4 cm in some varieties. The shoot consists of nodal units. each of which has an incernode. a DOde. an axillary bud. and a palmate leaf on a petiole (Cock, 1980) The stem is U5Ua1ly slender and glabrous and for the most part filled with pith and bcc:aIJe ofthiJ it i.J VCJ)' fragile untlilignification is completed. The: stem vvies in colour and it CUl be silver wttfl. li~ brown, brown or dark brown. The older parts of lhe stem consist of prominent knob-like scars which are the nodal positions where leaves were onginaUy attached The internodes vary considerably. depending on varieties and cmuonmenl (Onwueme. 1982; IITA, 1990) Two typeS of branching are observed in the caSilva plant (Hunt etaL. 1977). They are the forked branches w1Uch occur at the apel( oftbe stem when the apical meristem changes to the rcproduclivc ttale and it is often associated with flowering, and Lateral branches which arise &om axillary buds some distance from the apex due to unfavourable conditions such as disease The forked type of branching is synchronized with all branching occurring aI about the same time (Cocio. . , 1980) The hei" oIlbe cassa\a plant varies not only genetically but also with environmental conditions suc:h as aJtitude, tC'mperarure, insolation SOli fenility. lodging and whether !a\·C's are harvested or not (!\iweke el aL, 1992) "'or instance, cooJ ternpcralures are known 10 delay the time for first fork formation (Irikura t!l aI., 1979. UTA., 1990). High lemperatures above2rC. on the other hind, reduce forking height IKealmg, l'/H I) Long photoperiods ca&Je pus to braac:h lneraJ times within a short lime and the total number ofacti~aplces isgreat1y iDCreaJed. TlIDeofplantins also affects the branching height of University of Ghana http://ugspace.ug.edu.gh CUY .... (lITA 1990). lDtercropping with a more competitive species may alter the branching pauem and where there is competition amons cultivated crops for ligbt. branching may occur at a higher level tha.n in pure stand. TbcJefore. branching height is standardized in reWivetenns The leave5 of cassava are spirally arransed according to a pbyJlotaXis of 215. easllva leaves have multiple lobes of variable shape. usually 5 to 7 although any number from 3 to 9 may occur A single plant may have two or three different leaf shapes. This is called foliar polymorphiun. The colour of the leaves. sometimes crimson when young. is light to dark greco The Luves are borne on petioles which are longer than the leaf blade aad measure S to JO em in leap The petioles,. like the leaf veins, are green. red to crimson andmorerareJy ..... hjti~ 2.J _portaace and .tiIi~.lioa of Cassau iu Sub~Saharan Arrie. C"'VII (MtJlflhot ~fCV/~nlQ CranIZ,l, is a root crop that onginated from Tropical America. II IS cultivated and consumed as • staple in many regions of tbe developing world. Sub- Saharan AfriCi. is the world's largest producer of cassava. Cassava production in 2005 was liB 51 million tones of fresh storage roots grown in 12.07 million hectares (fAOSTAT.2007) Over qa-/. of production takes place in small farms in rural areas (Spencer and AIsociata, 2005). Cassava is Afiica~i second most imponant food crop (Nwekc 1'1 tJl. 2002). This is because: cassav. produces exceptional carbohydrate yields, much bigher than those ofmaia and rice and second only to yams (de Vries el aI. , 1967) Cassava is now the largest single most important source of food energy providing over ) 7% of'the calories in the diet at 0YeI SOD million people In tropical Africa (H.hn and KeyseR, 1915, Horton and faao, 1985). Major producing countries (fAOSTAT. 2007). Include Nigeria (41 56 millions lones). Democratic Republic of Cnngo (14.97 million University of Ghana http://ugspace.ug.edu.gh tooes), Mozambique (1146 million tones), Ghloa (9.51 miJlion tones), Angola (861 million tooes), Tanzania (7.0 million tones), and Upnda (5 .S7 million tones). The leaves of.,..... pIut wbi arc also used u feed for fum animals usually to IUbltitute for part of the Cllillattons of eaaaava described above are predominantly for white flelb CUllva \,lne!les meanwhile there are lOme localattnsions whh yellow Oesh ("~ BodM", .... hleh are also uxd for food, Such ydlow Oesh cassaVI Kenolypn contain beta carotene University of Ghana http://ugspace.ug.edu.gh 2.4 Eovint ••a lW Req_ire.eou Factorsaffeetinstbe productivity of cassava can be classified into three broad classes physical (climatic and edaphic:), biologicaJ and physiological . The major physicaJ factors. Include soil moisture availability, temperatw"e. light (photoperiod and intensity), !lUmmI. pH. and relative humidity . Pests and diseases constitute the biological factors. wbi~tbephysiol{lglcal fattOfi&re inherent in the development processes necessary for the anainment of characteristic form and function. This depends 011. a chain of interrelated eVCIIlI which ~ sequential in time. gene-rquJated at critical sites and timn and modified by environmental influences (Whyte, 1985). l.. .. ICli. ..t ic:r.cton Cus. .. is growa ia a wide:- range of emiuonmenl between latitudes. 30" N and 30- S, aJlhough the bulk of it is 1(roWR between 200 N and 200 S (Jones, 1959). Within these lalltudes. environmental factors such as temperature, rainfall, solu radiation. and soil ..:ondllions have strong influence on the physiological processes ofa cassava plant and ulumately liS yield (Code.. 1983). CUSlva is cultivated in soils varying from rich loam to poor and. at altitudes between .. level and 2000 m. where .,,·craSe UlfIl1Il temperatures are between 15~ ad 35OC. aDd antk1a.I. rainfall varies from 500 to SOOO mm In co.staI zones and ill some monsoon climates, cassava produces an acceptable crop outside the tropiCS This IS illustrated by larse scale C85Slva cultivation in Southern Queensland ,Australia), the South of Brazil and Natal HI South Africa. The h;shaI _. root produaion an be expected Ifl the tropical knvlancb below 1S OO m allitude (Tindall 1913) Al ahnudes above 1800 m. it develops only very slowly and it is susceptible to &osc (Janssms. 2001. Yanock. ,.,al. , 1988; Hahn and Keysen. I98S) University of Ghana http://ugspace.ug.edu.gh 2.4.1.1 TNlpcnla.re Sprouting is imp&Jred when soil temperalure are below 17"C However, time lO e.ergence decreues with tempeqture up to 10"C, dependiftg oa the variety. Higher 1011 temperatures also reduce germination (Keating and Evenson. 1919). "The optimum plant e'Towth of cusaVl was observed to be at 1O"C soil temperature. Rare of plant grOvM at 6 werts after uusplantW,g was 0.26,0.97.0.38 and 0.05 em per day, respectively for soil lemper~ regimes of 22, 30. 35 and 40 Of; (Lal. 1974). Temperature differentiaUy atreas the different phases of root bulking Where temperature mA)' favour storage rOO( mitiation. it can reduce root growth ud lor maturity. which tends to be complicated by dlyaDd niaht temperatures Low rugh! temperatw""et favour storage root initiation wMe high day temperatures (2crc) 5Jightl)" increase PhoIOS)·nthesis with high rate 01 ~'q)iraioo (ClAT, 1976), Higher numbers of stOnlse roots are produced at low night temperatures while larger roots are formed 8t higher temperatures (Bodlaender. 1960) High temptraturc. combined with &ons days. or 10\\' temperature combined with shon Gays, delays sto~e root devdopmcnt (OsiN el, al. , 1995). It it djfficult to separate the effect of lOil1CmpetatUre from that of soil moiSiwe !Iottess, since high soil temperature is always KCOmpanied by high soil moisture Itre$S 1.4.1.1 Lit. . , Cassava is a sun-Io\lng plant tbal. needs plenty of 5Urtlhine Any mcrc:ue or decreue iD ;;olar radlation will affect the size of the plant and hence yield OWUl8 (0 the mmlmal differences in day lCfl8lh in the tropics. photoperiod may not play • major role In the rroductivity of caua\"I Shon·da)) conditK)fU, howt'\('f, promote root bul~lO~ (Bolhius, l%b), poulWy btcau.sc: 1t0f'l3e root indUCing substance is fonned under lhiI pbocopcriod !'\o~be_ 10118 days promote stem gro\Wlh and as such limit the supply of assimilates 13 University of Ghana http://ugspace.ug.edu.gh 10 the storqt I'OOl and then,low down tuberization (Lowe el w.o 1916). Mosa: varieties of c.assava initille SlOf"I.8'C f'OOIs only under sbort days (10-12 hours) resuhing ill bigh storage root weist- sad SlOQ8C (1)0( number The optimal day leagth for root bulking in cassava seems to be 12bours(Bolhius.I966. Otoo, 1983) Higher light intensrties favour root bulking (Bodlaender. 1960). Shading has been found SO ..-kedly affect rootgrowtb. rate with link: effc:d. 00 top growtb rate (Cock etaL. 1979: KumIr ud Hrishi. 1979) Code e/ al (1979) found that shadin8 1095% had little effect on ae.va old« than 30 days, while higher shldinS caulCd f1Ipid leaf abscission The dechne in pbotosyDlbctic rates with leaf • under higb ligbl intensity seem to be genotype specific. s.ince different rates of reductions were observed among the dOMi lested by Aslam el a1. (1977) 2.4.1.3Wa_ Although CASU\-" IS tolerant to drought (On..-.ueme. 1978), higher yield levels are obtamed with a tonsa- moisture cycle or with c::on5CfVation by mulching (IITA, 1982) Despite iu drought-tolerance, rt needs a minimum amount of water of 500 mm per year sprad over siK monthJ The optimum annual precipitation requirement for cassava pvwtb lacs bctW'CICII 1,000 and 1.500 mm. per year. Cassava can survive dry periods of about 6 moatbs or more (Hahn ef aL , 1m). However. an ample supply of moisture is euefttiai during the first month or I'M) after plantins (Onwueme and Sinha. 1991). Fresco (1986), hasnotedthat yields Ifom cas.sava planted in the late rainy season are Ilkely 10 be lower than those planted lithe onset of the rains because: the plaming date mfluences yield since photos)nthesis IS likely to slowdown durina thedty It'UOtI. Silvatre (1989) hu abo rqIORcd tbIl during dry seuon, cusava lIorage roots Slop growing and sometimes dec:reaR in Wf'ighl 0..-.;n8 10 a loss of water while their starch conlent University of Ghana http://ugspace.ug.edu.gh incrc&seI. Ghuman and LaI (1913). found that uTlSauon significantly increases root yield and rOO( diameter. with these effects being more pronounced in unmulcbed than in mulchedt.ratmenlS 2.4.1.4 So. Cassaw is growa in &1mott aJllOil types provided they are not waJer-logged. 100 shallow or too ilOOy, butbeinS. root crop, cassava does best in deep. friable. well-drained sandy~ day soils which permit enlargement of the storage roou. Cassava tolerates a wide range of soil pH from 4 to 8 0 High yields are obtained in a deep. loose permeable soil with hlSh humus contcnl . On account of the: formation of mycortb.izu, C8SSl\'. thrives on desaturatedsoils with klw phosphorus content. But soils that are e~cessively fertile and especially those with an excess of nitrOgen limilluberization (Janssens, 2001; Vanock d g/ 1'lltH) H.igh fenllity may result In excessive \'cSc:tatlOfl gtowtb at tbe expc:a.se of !CO,. root aDd starch formation Cassava will produce an economic crop in exhausced sotls unsuitable for other productKm and consequently is often the lasl crop taken in the rot&hon Ul shifting culliVldion It is nbawtive of pot&uium. lmporuuu soil physical .nd cultun.l £acton tbII affect cassava production include soil temperarure. roocing depth. mcthod$ of seedbed preparation and soil erosOl which reault in 10. of fertility (Hahn el a/.... 1979) AJthouab CU$aVI yields relatively well on poor soils in comparison with many otbIr oops. large :wpplies of ootrienU are neces.suy for its production. Casuv. root )leldJ are ah.o influenced by I('lil tcmpeTatures, e.pecially lemperature regunel thai unfnout-.blc to root growth (WbyIe, 1915) University of Ghana http://ugspace.ug.edu.gh 2.4.2 Biologiulraeton The biologjcaJ corutninu, especially diseues and pesls. are among the factors thIJ contribute k) ~w productivity In West Africa. production risks of CUAva are ~ actwne &gronoaDc: cooditions and pesu easily combine to reduce storage root yielcb: by about SOo/i. (Herren and Bennett. 1984). Pests and diseases cause severe yield losset ia CUIIv. . the exteo! of~u can be u high &S total crop fiUlure, dependins OD the type of dlseue or pesI and time ofanack. Pests ofcas.sava are grouped under four main headings (UTA. 1990). Venebrates, nematodes, mites and inHCti while the major diseases of CUMva are leaf dilCalCS. stan diseases and storage root roC 2.4.2.1 Cassan Vertebrate Pests In Aiica. there au two major "'encbralc pests of cassava They are tbe Afriun buahfow~ Frc.tcoIiml$ blCalcararus hu..: a/caraJu.s and cane rat T/ryonotrty.f nt',ndertantl., Bushfowl become pestl only after the storage roots have been formed and after grain crops have be. bunsled They peck at the toil Yoith their beak until contact is made with the .onge roots upon whICh they fcccl- S~e fOOCs damaged in this way are easily invaded by rot~n[i: mlcro-orgarusms, 1eadins to their total lou. In bighly infested areas.. storage root lOiS resulting from bushfowl damage may be as high IS 300.4. Cane fWlJ at cas.sav. stcmJ and storage roots. They dig at the storage roots, and the WOUIId.t lDide 01'1 large Itorap roots during feeding become s.ources of infection for the ~m.aJ.ler IlOfI.gt r~s. On unprotected farms. yield losses can be u rugh as 40% 2. •. 2.2 Cassan IDseet And Artbropod '"Is Many species of nematodes are Ir.nown to be assuciAted wilh cass.a\ a. They IOfca lhe rocxa _ reMer them more SUsttpllbie to l'Ol-causing orpnisms The root-knot University of Ghana http://ugspace.ug.edu.gh n(malode, Mdmdogyne ntCOR"IlQ, is • particularly serious problem in Africa', cassava- grOWIng arU:!i The lesion nematode, PmtyIenc/w£s bTachyunlS, the spiral nem&lode, He/":ofyk,,,.httserytJurntNand tberenifonnoematode. R«yIenchlllvsrenijomt areal,., found on cassava. An attack: by these pests cause!. the plant lO 101e viaour and the ruulring yield I.,.... range bct~ftQ 17 and 50'10 (IITA. 1990) The cwoomicaUy important anbropods are mostly CXOlic species Notable &mo" theIe arr the ca.a't'l. mealybug (PhtlJOCOCOI')' I1ttIIIIhonJ, c:au,ava green mite (MononydttlhlS ' ..n u/flO), ",hiteflies (AlnuodJ(:MS dlsperl.1ls), and the larger grain borer (Prosupharn4 IrIIfk'(1f1U) , Duri", the 1970s and 1980s. cusava mealybug and C&SSAva !(rec:n mile plagued Ihe ca»lva bell in Africa By the early 19905, however. the mealybug was under cfTeaive classte&.l bIologIcal control. mainly by lbe introduced parasiloid Apoanygyrus (f.,.,d/IfQCQI"!,IS IUPCl) (Haren and Neuenschwander. 1991), The green mite bas been the mllor wnliDeDl-wide pest problem causing 30-10'/. losl in root yield, depending on 'I<\cntyoftheaaack IITA'ssearch for sustainable solutions to Ihe mite problem focuses largely 00 tbeUIC of exotic prcdatory mitcs{phytox:iid.ae) foru.i.u biologicalconarol campajp (Yaniaek and Herren. 1988) The ,itUJtion has changed with the introduction or fetronydtus anpo in Benin, Cameroon. Ghana and Nigeria In on--farm trW, T, QT/PO rtdUQtd the pest f'MnnonycNII. .., 1ana~1Q) populations by an average of two thirds with root yields ~ by a third in the wpt areas where the exotic DItutaI enemies wne The spinlling ""hitefly, AI,'IIW,b('us dJsperSll\, a nali ... c species in CaribbeaD and Central Arnmc.a. has in recent years spread into West and Central Africa (Neuenschwander, 1994b). The pest wu inuoduoed do Africa sermdipilou.sly with two aphclinld JWUitoids. Ena..-~a hutf~tt..m aad Ew::crsta XI,CMkltJuptW, which are aening bio&ogical conuoI i.a I*U of Well Amc. (d' Almeida ttl al. . 1997), However, a more effective 17 University of Ghana http://ugspace.ug.edu.gh tontroI woWd appear to require introduction of other naturaJ enemiol. for example the pRICIavyoocciaellid ,"epltaspl~sp !be larger grain bon:r i5 a neotropical pest droduced ioto Africa In 1981 &om Central America (Dunstan, and Magazine. 1981). It is a key pest of stored maize.. but in dry processed cusa~. . Crupi it causes up to 74% loss in biomass after .. mooths of infestation (Hodses el oJ . 1915). In pans of West Africa, classical biological CODtroI of the peS! in .... maiz.e by the lDtroducod bisterid predatory beetle T~retrlosoma nlJ(Te:;Cfm bas been established (Borgemeisler. d oJ .• 1997). The prtdator &Iso appears to be a poteDli&Ily efTccti,,~ bioLogical control candidate against the pest In stored dry cassava (H,lbigandS ul I...cIffu.Dpl disease is Cercospora teafspot. There are threetypeSofCercospora leaf spot The most common one i, brown leaf 5pOt, caused by O!rC'V!.pt.mdlUm MtullltgSII The othel" types are leaf blight. caused by ('acospora vrcu.'it:K'" and the while lcafspol CMlsed by Cercospora canboe Allhough :)tvue attacks by these micro-organisms have been reported in sevcnl Afiiean countries. they are not known to kill cassava plams The symptoms arc n::stnc1ed 10 older leaves and set in after tuberizalioa has ocxurred Yield Ioues arc minor for white leaf spot and ksf blight but may reach about 2004 for brown 1cafspot(IITA, 1990) The most important cassava stem disease which occurs in all major CUIIVl-growlR~ areas in A6iQ is the Cassava Anthncno'>e disease (CAD) II is aused by CoIl(,lOtnchu," gkwfJ~3 r. $p. malllhofu. The w.p-suclClng coreid bus. P~elldotherapItU cktlUoSklll.l , IS reported 10 be partly responsible for the spread of the disease (UTA, 1990). The fungu:!o .tuck.smainlythe stCRl,I"\\;gsand fruits, causing deep wounds (·canlcers·), leafspottllll/: University of Ghana http://ugspace.ug.edu.gh and tip die baclt . The incidence and teYerity of the disease have not been conelated with yidel loss in the field but the infected Items produce poor quality plantins materiafs wttich do 001 est.1blish well in the following planting scason and thus yields are reduced Soil-bome patho~s I1UCk cassava roots, causing damping-off disease at the early stages of growth or soft. rot or dry rot in storage root prior to harvest . The most importanl diseues are (i' Sclerotium rot, caused by • fungus. SclerotIum roIftil, lhis is the mos! (;(IIIIDIOII itOraae root disease and occun on roots and storage toots at aU ltages of devtlopmenl It c&a be rewgnized by the appearance of • white mycelial growth OD jOfected roots A$ the fungus penetralC$ the storage roots, the plants begin to show mild wdting symptoms (u) Soft roc storage root disease· caused by Phytoph,hora dncJulen and fusanwm wIam, aDd occurs under wet conditions and cooler temperatures. 11le cau.sal orgamsms attack and kill small feeder roots and cause necrotic brown leslons on older rOOlS As the rooti decay. they infect the storage roots which then emit pungent odours Whrn foots roc. the entire plant witts.. defoliates and dies. (iii) Dry rot storage root ditc:ue cau_ by ICvaaI fungi. including Fomes I,gnu.ul.t. A,.""I/ar,dlu ",elka. H,~/lImo n~'·QITIX and Borryodiplodia Ilwobrotrt«. The disease uUtally occ:ut5 on land thai has recently been cleared of trees and shrubs lnCected storage roots are typic.lly toYemI with rhizomoJphs (thread·like network of mycelia) of the fungus The plant wilts, bua does DOl shed its leaves Eventuall)" the entire plant dehydratH, turns brown and 1.4.2J..4 Cassa\.W«ds Weeds can (&U~t= as high as 80% produc:tion loues (Akobundu. 19KO), if left unchecked. part.cularly dunng the fir« 14 months after p1llllins The common weed speCies in cana,"a agroecoS\ stems Include gr&s$eS e 8 spear grastes (Impuuru cylmdruxIJ. 21 University of Ghana http://ugspace.ug.edu.gh bermuda grus fCynodon dactylO#t). guinea grass (POIUnmt ...arjMrUfl). feathery penniIdum (penni. .- po/ptacluun); sedges e.8-. purple nutsodse, C)pgjca1 conditions with regard to HCN content Although the glucOiide content nlUeases with an increased rate of nitroscn fertillze.- application. potUsium and farmyard manure application tend to decrease it Hahn el al. (1977) reported (hat low c\'arlldcrontentincas.sa..-aappean;toberegulaledby.,ece~iveminorgenecomple)( 2.4J.2 Han'estlades £be physiological and biochemical prOC05eS occurring during lhe development ofa plant are Integrated so that an equilibrium state is established al all times dunng growth, differentiatioo. aDd development Changln~ the internal equilibrium alters the final product and the exteat of Ihis Illeralion in relationship to yield is dependenc on the degree of association between the two (Whyte, 1985). Allhough root yield IS hl~hly correlated 21 University of Ghana http://ugspace.ug.edu.gh willi IIOtII plUII weight within a single 8COOtype at various staBes of plant growth (Boerboom. 1978b, de 8ruijn., 1982; Tan 1980). this reJationship docs DOt always bold tNC: acrotI genotypes In other words, a large plarC does not ncceuari.Iy promise a bigh The Iwvnt index. \\0 hteb is the ratio of root weight over total plant \W'igbt. is therefore a paramder which reftcas the dry matter distribution within the plant in favout of rooc yield In a aop such as cassava WMft the economic yield eomes from a vegetative pan (specifK:ally. the adventitious roots which are modified imo storasc organs) the harvest Index is senerally nuch larger than may be expected from a crop whose economic yield results &om fruits or seeds, !UGh u grain legumei or cereals (Lian. \985). Also structuraUyspeaking.higherharvestindexesarepossibleinrootcropssincetheplantis not required to "hold up" a heavy yield (Coursey and Haynes. 1970). Therefore harve51 indel: bas been found 10 be one oftbe most important parameters in the selection for y;eld potential In cassava (Lim. 1985) A genotype with a high harvest index may be assumed 10 be ph~l)' more efficient. since most ofib dly matter production is channelled towards SCclf&!Ce in the rOOls. Howtwr, fOOl stonae lal.;c) I lower priority to top tp'Owth wiIban • cassava plant Dry matter storage in the rOOlS n~sulls from any surplus over dry matterrequ&remcnts for the produc:tion or new leaves.. maintenanoe of existing leaves, and maintenanc:e and weight gain of scems and branches This was experimentally dnnoutrIaed by lopping plants to arrest leaf produCtion. res.thing in increased dry matter University of Ghana http://ugspace.ug.edu.gh loU.J CuotNOidli J_ Cassna Carotenoid. aR Datable fOf theif wide distribution.. structural diversity. aDd various functions More IhIa 600 carotenolds, not including CIS and trans isomen, bave been ilOlatedandcharactenz:edfi"omnatucalsourc:es(Pfander, 1981) The normal while root cassava genotypes contain ooly small amoullU of beta-carotene (Bradbwyand Holioway. 1988) Nil yelLow root caiSl.va contains up to aboUlIOOtimes&s much (McDowell aDd Oduro, 1983), Beta-carolene is the predominant carotenoid in CUMVa, but u • mixture of the In11U- &Dd as-forms (Rodriguez-Amaya and Ktmura. 20(4) Howevcr the determination of the trans- and the cis-isomers individually makes the analylis I'DOfe expensive and compJica1eci. Because the Cis-isomers of beta-carotene are dlfficuh to obu.i.a., their quantification is dooe usins the trans- beta·cuocene curve C-... like sweet potato does AOl contain etherified carotenoid, and has Low lipid contmt; hence saponification is unnecessary Bda-c&mtene, u-c.arccene, and be1a-cryptoxanthlO are provitamin, A. Structurally. ntamin A (retinol) is essentially ooo-half of the bcta-arotenc mo1ecule. Consequently, bett-arotene is the most potent provitamin A, it is also the most widespread (Rodriguu Amaya., 1993). Vitamin A activity ofa carotenoid is the result or an unsubstituted betl- ""8 wilh an ll-Qfbon poIypDC chain Carotenoid. hay.e beeD credited witb other beneficial effects on human he.a1th cnhanoemeaI of the immune response and reduction of the risk of dcgent.. ... tlVC:: diseases sutb as cancer, cardiovascular diseases, cataract and mascuJar degeneration (Astroa. 1997; Bendich. 1994, Burri, 1997, Guiana and Hennckens., 1993. Krinlky, 1993; Mayne 1996; Olson, 1999a,Olson and Krinsky, 1995) The acttonofCll'Otenotd.saplR~ dlscues 25 University of Ghana http://ugspace.ug.edu.gh bas been attributed to an anlJoxldard property, specifically, the1r ability to quench singlet oxygen and interact with free radk.als (palozza and Krinsky, 19(2). Other benef10el include C&lClnosen mee.boIism. inhibition of cdl proliferation. enhancement of cdl dilferentiauon, scirmJJ.atioo of cell to ceU communication. and filtering of blue light (OI"",'999'and'999'j. 1 .•.3 .5 Factors arTe('tinR quantity aad composition of carotcae Foods vary qualitatively and quantitatively in their carotenoids compoa.ition Green ~~c:tabIa. lCIIfy and noo-teafy, have lutein, ~tene, violaxanthin, and neonmhio AI the principal tar01et1OidJ with defined quantitative patterns The relative proportioOl of these carotmoids are fairly constant, but they vary considerably in (heir absolute , Carotenes predomirwe in the few carotenogenic root aops (e g caJTol. sweet polato). and \Jlnihopnyillpredomlllilcin m&iz.e(seed). QuaJitativeand. quantitativedilTerencescxist In a gi'l'tl'l food doc to fKcon aid! u variety. .. ofrnaturity. climate/geographic site of produdlOft., part of the plant utilized. conditions during agricultural production. ~ Mn,'e-sabandling,procnslRgandstOtageoonditions Differences in carotenoids among cuhivatS of the same food are well documenled and can be either both qualitative and quantitative or only quantitative (Gross, 1987, 1991 Rodriguu·Amaya. 1993). Mean be~ contenl of sweet powo CUltiVUl, for euJTtrle. "&on from 10 to 26,600 J&8IIOOg (A1mcida-Muradian and Penae.do, 1992. Hqenim&fta et 01... 1999. Huana el aI. • 1999. K'osambo el oJ. 1998. Takahala" aI., 1991) Stage of I'nAlurny is one factor that affects earotcnoid composruon Matundion in \'egeubles and npcning in fruiU are generally accompanied by enhanced carotenogeneslli University of Ghana http://ugspace.ug.edu.gh (Arima and Rodri_-Amaya. 1988, GrOll, 1987, 1991 , Meread"". and Rodripz- Amaya. 1998, Rodriguez-Amaya. 1993) F.-mins pnctic:a may also influence carotenoid composition For example. companson ofblc cuhivus at the same stage of maturity from natural aDd convemionai farms u$ing agrochemicals. rc\-uled significantly higher concentrations of all constituent carotenoid! In samples coUected from the DIIUraI farm (Mercadante and Rodriguez-Amaya, 1991). In contrast. a comparison betWeen conventionally produced and bydroponic leafy lenuce save no significant difference in the con51ituenl carotenoids (Kimura and Rodripz:- Amaya. 2OOJ) 1.4.3.6 Effects ofpl"Oceuiol on carolrooids \fany carotc:nogenic foods ICe seasonal and processing at peak harvest minimizes los_ and maka the products available all year and permit transpOr1ation to other places Proccuina and stlX'l8C of foods should however. be optimized to prevent or reduce dcgrad.llon",hliC'.x:entWl!insbioavailability Pc:rccnt rdcntion or to. of CItOIcnoidl ~ processins and storase of food has been rt'pOrtcd. However, despite some experimeJa.l inadequaCies and discrepancies in the data.. wme conclusions can be drawn (Rodriguez-Amaya, 1997) Carotenoid biosynlbcsiJ may contirwe., in tiuits, fruit vqctables and root crops even after harvest, provided the plant materiaJs are kept intact and the enzymes. responsible for carotcoo!!cnc\i, are prc$Cnl Ifowt'\cr In lea\'cs and other ,,·egetables. post harvesa dquadaaa of carotenOids may pre. ...... I. especiaJly at high storage temperatures and under condlhonslhalfa\'OUrwilting University of Ghana http://ugspace.ug.edu.gh CaroteuoidsarellltUJallyprotecteclinplanttisJues,howevercutting. shredding,choppiPs and pulpinSofftuits and vegetables increase expo3Ufeto oxygen and caused carotenoid Whlteverthe proce~iag method. carotenoid retention decreases with lonaerprocelsins time, higher processing temperature. and cutting or pureeing of the food , RapKS proc.asing a1 high tcmpcnlure is a good alternative. Current knowledge therefore suggests that proceiiing conditions should be optimized 10 minimize losses of carotenoids ..... hlle~ha.ncing(hcirbioavailabilily 1. ... 3.7 Geaeral proced.ft for caroteaoid anal)'sis ill cassava There is substantial quahtative and quantitative variation In carotenoid composition of • foods. ' Even with a particular food. compositional variation occurs duc to such factors as varidy/cuJtivar. seographic or climate effects, season, maturity and part of lhe plant ullh/ed Thus, conclusive identification of the carocenoids in a food sample should be MXOmphshed before quantifical~n is carried OUI In seneraJ. iI is sufftcient. to quantify only the principal carotenoid, Quantifying the minor carOlenoids increases analytic. . complexity, requiring chromatographic resolution. identification, and standards of the different carotenoid,_ These aa introduce more errors besides malanR the analysis longer. laborious., and costly Theadditionat resu.Jtsobtained are often of no practical use When oomctous samplcs have 10 be analyzed. such as in selecting varieties or breeding lines. that meet the des.ired provitamin A level. it is costly and UJlBfICessary to go directly 10 HPlC quantifiC8l;on. A degr« of accuracy is not needed AI Ihl5 POint Simply mexpensive and rapid ICI"eeainS methods thaI verify if a samplc is above or below the University of Ghana http://ugspace.ug.edu.gh Wg« level CUI be used to se]ect tbose that are likely to meet the desired levels The ac:ante but Cl(pensh'c HPLC method can then be used only for the chosen samP'es. 2. ... 3.7.1 S. .., I'-I To obtain meaningful and reliable analytical results., the samples must be representative oftheentU"elotUDdCl" investigatIOn and adequ.a1cly prepared roranalysis. Acx:ordinsto K.raIochviland Taylor(19l1). the major steps in sampling are t t' lden(ification of the population from which the sample i. to be (:()1I~ted ~ (ii) Sdeccioo and colIcdioo ofsamplcs.; (iii) Reduction of sample to alabol'l1Ory-tize sample suitable for analysis Horwttz (1988) defiDed. &n)1hmg sent to the laboratory as a laboratory wnple and '::Of\Sldtt~ reduction of the laboratory sample to a test sample for anal>"is as part of the u.mp1ma proccu. Pomeranz and Meloan (1994) differemiated sampling and sample prc-puatton as follows the aim of sampling is to secure a ponion of the malerial that .... 1tsfactonly represcau the whole.. wrule the ptUJ)OtC of aample preparation i. to oomogMlU: the luse sample in the laboratory aDd subsequently reduce it in SIU and amount for analYSIS Once the samptiaa ~e and time of collection are decided, the following questions should be add>-eued (KnIodTVil and raylor. 19811 la, How many samples should be taken" (hI IIowloqjcohouldcocbbe? (e) From wba'e in the bulk matenal and how ahouJd they be taken" (d) Should indl\'idual samples be analyxd, or ahould a composnc be prcpatl"J ' University of Ghana http://ugspace.ug.edu.gh To evaluate c.bangeI ill composition as a function of variables such as time, temperature, and kxation,. sysaem.mic sampling should be used and the results should be statistically 1.4.3.7.1 Sample pftPlrau. The purpose of y.rnple prrparation is to homogenize the large sample in the laboratol)' and sublequently reduce iI: in size and amount for analysis. Following this rationale. sample preparation includes all operations between the receipt of the laboratory samp&e and t~ welgh1ng of the sample to be analysed The sample thlt i. brought to the laboratory is usually too large. both in bulk and in particle size for direct analysis It mulA therefore be transformed into I homogenous. small ample for analysis. while maimaining its represeRlati\"ity Homogenization ,nd !lib-sampling rRly be done simultaneously or consecutively in either order Physical operIIionl, such as chopping, c:uttina imo pieces. mixing. milling, blending. llnd sieving. are carried out along with bulk reduClion, such IS quanering or riffling The proceu can be pa10nned manually or by using commercially available mills, blenders. grinders, and nffiecutters. The food product is usually analysed in the forrn in which it is consumed therefore inedible portions (e g. peel teed, shell) are remo\ cd prior to sample p«pam. ... Ac:cor b Iossofplantmaterial C difficulty in removal of extraneous material from plants without removaJ of plana COnstlluentslncludinttlheanalylc, University of Ghana http://ugspace.ug.edu.gh d. enzymaticcb.angeibeCoreanddurinsanaJysis, e compositiooal changes during grirKhng, r cbangct ill U81Ubk components 2.4.3.7.3 Acetone phase Extraction of beta carotene -\ good extraction procedure should release all the carotenoids from the food matrix and brins them into solutiOn, without altering them. The solvent chosen should efficieptly cxtractaUcarotenoidspresent in the sample hlraction. partitioo and open column chromatography (OCC) should be carried out under a fUme hood to pn:ua the aualyst tiom inhaling solvent vapour Breathing hexane, for example., should be avoided due to neurotoxicity of some of its oxidative metabolites , (Schlel.iI and Liaaen-Jensen, 1995). Because the solvents used in extraction or partition Will uhimately be removed or at least reduced by evaporation, solvents with low boiling pomts should be cm-n to Iv<»d prolonsed beating. Thus the lower boiling fractions of petroleum ether (b p ls.w- C) should be used instead of the bigher boiling fraction5. When cxtnc.tins c:aroIcnoids from biologic:al sampleJ,. RIch as roods like cassava, which contain luge amoUDII oCwater, a water-miscible organic solvent (e g , acetone, methano~ edaano~ or mixtures thereof) should be used to allow bener soh'ent penetration Acetone has been widely used for carotenoid extraction, however, the advent of high performance hquid dvomatography (IfPLC) hM .... tetnhyrle\WI.,.".no_ Fig. 2: Monthly ral"~ys at Wenchl aerie:. Stltion from July 2004 to JulyZ001 University of Ghana http://ugspace.ug.edu.gh Aftu the (Ofeti-lft'aOD,Ih (r&fiSillon zone, the field experimentation was eXleDded to the Semi-dcciduous FOf'S:. Thi~ zone is distinguished from the rain fo~ by the fact thai many of the trees in its upper and middle layers edUbit deciduous characteristics (shedding 0( leaves) durill8 tbe Ions dry season, usually from November to March when the influence oftbe barmattan is 8fUlly felt . It has 1~"O rainy seasons March to July and September to NoYembcr I..Dd the annual rainfall is between 12.50 and 1750 mm (Boateng, 1960, Dickson and Benneh, 1988). The soil is generally alkaline., containing grater quantities ofMrients because tbeyare less leached by rainfall. The soil is suitable for cocoa, ootree, oil palm. maize.plantain.c:ocoyam, cassav&,ric:eandvegctabluincludIn8 e!/.8plant, beaM. pepper and okro (Bo&tens, 1960: Dickson and Benneh, 1988) The Plant Genetic Resources Research CeDtre (pGRC) experimental farm located at Hunto was the area selected as represemative of tbe dcxaduous famt agroccologica1 zone TIlt «petunenl swted in 2005 on a land area of about 0243 ""hich was cleared, ploushed and planted on 22'" July 2005 The foIlowins yeaT an area of 0.273 hi was ploughed and plamcd on. 4a. May 2006 The monthly ramfall and rain days durina the two cropplosyearsareprr:senlcdinFigures3.nd4 University of Ghana http://ugspace.ug.edu.gh I j " "i ~ C1 .:.....~:.~.-:.: ". ' " -..- Wo, ...,. Fit . 1: Monthly f'lintaK at BURSO ffom J\lly 2006 to JYM 2007 Fig. 4: MontNy rain days at BuMO from July 2006 to June 2007 University of Ghana http://ugspace.ug.edu.gh The third asroecological zone Coastal Savannah forms 7% of the land area of Ghana rrustypeof~noccursin'hedryequatoriaJcnma1icregion. Thisist.bezone which receives the leal amount of rain in Ghana between 740 and 890 mm annually Relative humidity is.. however, high throughout the year and thus compensates for the !CIl1ly annual rainfa]l (Boateng, 1960; Dickson and Benneh. 1988) It ha5 two rainy SCUOf"I,S The major raiay ~n is &om Match/ApOllo June whilst the minor is from September to October Relief is gentle and soils are either heavy clay or light textured and underlain by clay The toils are generally acid or mildly acid. Among the crops grown are ..:assav ••n d maize. VC!tctahlo are grown 00 lighter soils while rice. cotton and sugarcane are planted OD the beavier soils Coconut is found on the coutaI frin8e The specific area selected as the coastal snannah agroeologie&l zone was the Crops I Research institute Statioo 11 Poku.ase where an area of about 0 .273 ba was cleared, ploulhed and plansed on 26· April 2006. The characleristics of me rainfall and the rain daysduringtbll aoppu1& w.uon arc desaibed b)· thc FigurcsS and 6 As presented above the number of loullons Increased from one year to another hued on a\41lability of planting materials. Combination of locations (Wcnchi. Bunso and Pokuut); yean (2005·2006 and 2006-2007) and harvest ages (9, and 12 or 14 months after planting). ~avc • lotal of 10 different envir0nment5 in which the experimental lNIeriabwue ev,IUlled. Descnplions of the 10 environments arc presented in Table l University of Ghana http://ugspace.ug.edu.gh F~. 6: Monthly raln,.11 at Pokuue durtng the ...s on 200;..2007 Fig. I : Month)' rain days at Pokuue during the cropping season 2006 2007 University of Ghana http://ugspace.ug.edu.gh ~: DeKripliH ", tbt 10 ~ranlts ill which nine yellow reot ud OM dite root USSJIva genotyprs were eval •• trd ~ipalio. I N.';-~orlocatiOD-T Yearo(Hperim-eiti-y_etll• .wst -] I 1 ~1- : 9 MAP I ' EnviroruntaI2 1 \ 2005,2006 ~ ~ . ~En~viromneDI--:-::C::::-'l- --11 Wencbi 9MAP 1 ' 2006-2007 " fiW;P-' . j--- En_6 I 14 MAP IEavironm""7 IIIunIo iEnVironmem-S- 12006-2007 h:;,·--i I ' "MAP - - . I n\-ifonmcnt 10 I Poku&S(- \ 2006-2007 3.2 PlanliDg mltcriab awl Planting In the first year of the experiment in 2004, fifteen cuttings of each of thirty-eight (38) )'C'lIo\lo rOOl cassava genotypeS (Table 2) received from the International Institute of Tropical Agriculture (UTA) in !badIn, Nigrria were planted in three replicllions (5 CUI1Ul8spergenotypeperreplication)withSwhitcrootloca.lca.ssavavarietiesatWeac:hi Agncultural Station (Brong Ahafo). At harvest 12 months after planting. these genotypes wereevaIuatedfortheirfreshrootyield, drymattertontent, harvest index and yellowish colour of their root Nine of the yellow root cassava genotypes were selected hued on the yellowish colour of the fresh ston.ge root combined with their fresh root yield and lhetr dry mana content These genotypes logcther with one local while root cassava variety were c"ld.bhsncd at two locations Wenchi and Bunso. the second year otthe University of Ghana http://ugspace.ug.edu.gh ItXJICrime,. in lilly The experiment was repeated at Wenchi. BunlO and PoIcu.ase In the m.rdyal The 38 p:ootypes an: shown in Table 2. The selected lO genotypes were II follows 0111224, 011\235,011\368,01/1371,0111412, 0111417, 0111610, 0111442, 01/1663 and WenchiOOO I6.I..!&1: ·lllirty eipl ycMow root c:.assava ~t.otypa (rom UTA gUlIIplAsm --Ge~n.-ty-p.---SO GeaOfype -wliil - '20 " ~-' ·· t! '~~ 0111368 ~:;:~~~ =1t=-c 01/1273 0111551 I 23 01/1335 l-J Metbods 3.3.1 Laad p~rat ....1 Id r.cld I.yoel The RandornUed Compleu Block Design (RCBD) as described by Gomez and Gomez (1984) wu the experirnent.&l de$lgn used for aU the five expenmentattoM At Wenc.hi and Pob.auc. the p&ou were cleared and tilled with a disc plough to • depth of approximately .10 em In SUMO. no tilJaae was used after spraying htThicidc fC)f" land cleanng In each of the ~te the plot area was divided into three bIocb. Each block was then divided into ten University of Ghana http://ugspace.ug.edu.gh smaller plolS The number of location and the plot aize5 varied from year to year ac:conIing to tbc availability of planting matenal_ In 2005-2006 the plot size was 7 m by 6 m j!>I' rowspel'" pkJt..J,7p1ants perrow) ine.ch biock Fortbe 2006-2007 the plot size of 10 m by4 m (4 rows of 10 plants each) wuused. In all the experiments lbe cuttings were planted at I mx I m(between rows and on the row) J.3.2Wtt"doontrol From planting 10 harvesting, weeds were controUed using hoes. The flfst weed control was generally at two weeks after planting. A minimum of four weedings were done for ellChexperiment 3.J.J t'ield dala collection Field data collection begun one month after plantill8_ Data on disease and pests were collected every IwO 10 th~ months. Data on ItOfage root yield components, storage roO( bet. tIJOIene quantification and it. other mated variable. were collected at nine. twelve orfounecnlDOlllhsafterpLanaing J.J.J.1 Ui~ea'il' xort RalinR Afiican Cusava Mosaic: Virus (ACMV) disease infestattoa was evaluated 10 Uunso and Pokuue aI 1.3,6,9 aDd 12 months after planllng. (MAP) by usinS the followlOg scort rallA,: no symptom up to 20% of the leaf covered by light green symptoms of mosaic ZI· o 10 40". of leaf area covered by yellow symptoms of mosaic or apparent dcformauon ofthe leaf .1 41~'., to 60"/. of the leaf area covered by severe symptDml with di"lonlon and reduC110nofleaf$lze -J ~e~'!fos:~ Senotyptcmance(a,'): h' PhenotypiC (oefficierw: of Variation (PCV) was computed using (he formula (Sinah & Choudhary.I9I5) PCV = -@x 100 X WhereXistbeme.an 3.3.5.4 Geootypic: Cotmtieat or V.ri.tioll Genotyptc cocffacieaf: of \'Vlahon (GCV) was computed by usins the formula (Sinah " Ch.udhlry.I985). g GCV ;~X 100 X 55 University of Ghana http://ugspace.ug.edu.gh 4. RESliLTS 4.1 Spraulin,., two weRs after pIIIntilig Table 3 shows 1eveIJ of sprouting for .he genotypes two weeks after planting. Genotype 01/137) pve the lowest percentage sprouting (31 .33%) while genotype 0111368 save the highesllCOf'e(98 33%). From combined ana1ysis of variance (Table 4) tbere wua bighly \Igmficant differeoce among genotypes. among environments and genotype x cn\-ironfMRl interaction (p<0.001). The best genotypes were 0111368, 01/1663 and 0111442 Envi_ E" (polwose •• 12 MAP ror 2006-2007) gave the IUgIleS! sprout'. rate followed by environments e., E. .:I Es of the same cropptl18 year 2006- 2007 at 9 MAP 81 Pokuase, 12 MAP aI Wenchi and 12 MAP at Bunso, respectivety '\\(n~ num~ ut plaNs harvested per hectare is shown in Table 5. The lov.,elIt average number of plants pcr hcctare(S311) was recorded by genotype OJ/123S. whilc the highest was recorded by senorype 01/1368 AnaJysis or variance (Table 6) for the number of plants harvested per hectare showed highly significant differences (P< 0001) among genotypes and environments. fnptttively . Based on the least !il~mlicant difference (LSD S%),theg~cu.begrouped imofi ... ecalesories. environments can be grouped into four groups. F.n\'lrontneIUE.o. E.and &,correspondlogto 12 and 9 MAP at Polruaseand 9 MAP at Wencbi in 2006-2007 were the best. The G x E interaction 'lias .Iso signiflc.nl meanina some genotypes are DOl perfonning the same way for this specific variable in all enviroruoents Genotype contribution IOlhe total sum of'!qUIFeS (SS) wu 14 .....1 . while the enwonment contribution w." 35.42% and the G x E imeraction ICcounted for 1921%oflhelolaJ IUm of squares (Table 6) 56 University of Ghana http://ugspace.ug.edu.gh JtauIIs of the AMMI anaIy~s of the number of plants per hectare (Table 7) showed that the firsI principal component axis (PCA 1) of the interaction captured 41 590JO of the interaction sum ofsquarc=s in 20.98% aftbe intefaCtioa dquees offrccdom Similarly, the )CCond prlncipal component axis (PCA 2) explained a fi.uther 1981% of the G x E Inleraction sum of squares in 18.52~o of the interaction degrees of fmedorn. The mean squares for PeA I was SI~nificanl" P <0.001 4.3 S.mbforofll:ora~rootsperbectal't Table' sho\\ ~ rhe ...... mber of storage: roots per hectare The lowest average rwrnber of 21.378 Wb obtained (or the loc:aI check Weacbi 009 The highest average number" of roots (58 •• 83) was regiaered by genotype' 01/1368. For the environment, the highest , number of storage I'00I5 all genotypes combined was obtained at E, (59,133) and E lo (57,392) which corresponded to the croppil'l8 season 2006-2007 in Polcuase harvested at 9 and 12 MAP respecti\tel~ Combined analysis of variance (Table 9) thowed highJy signifam (P < 0.0(1) differences among genotypes. amung environments and for tile G 'It f intenKtioD. The Scnotype, environment and genotype by environment Interaction contributed 23 06~• . 33.960/. and 19 I 10/. respectively tome total sum of squares. 57 University of Ghana http://ugspace.ug.edu.gh L1!!I:&.1: Perc.mtale 'proulia, of nine yt'_lIow root Ind ont' write root nuava genotypes Ie two weeks .fter plIatiB. in 10 eovitoameots - -- r------- - in\'ironments Genotypes E. Ez. E, 1. 4" -oJ.} ~- "R; -~"' & E10 "h'aD ~224 - 5833 5500 66.67 ~fi3346T7 -i8nf-sr67 633l1-no7~ OIlI2JS 41.67 4500 5lj3 681.1 <8JJ- 46T7 4ooo~if 8ooolw-oot ~"''''i ~ 7l.JJ 7833 93.33 98.13 83 .33 5667 7500 95.00 91.67 98 . 3f~i4.33"· >omm- 40.00 33.33 90.00 - 86.67 60.00 46.67 6500 6500 8313 88.33' 65.83' I . 0/1/412 63.ll 61.67 5667 71.67 7667 55.00 8667 78.33 78.33 8667 1 71.S«fJ l 011/417 63.l3 55.00 8lll 95.00 IS 00 ,S33 6167 6833 7l.l3 90.00 7J.J3w IIvim 6133 86 67 10 00 9000~ 6OTol-ssoo -it! 131- 8S00~'S.33" 10/11610 3667 30.00 13.33 88.33 66.67 51.67 1333 86 6iT8JJ3f-om 7o:67"i " iiii/663 fssoo " 831~ 81.67 9167 61.67 IJ33 9000 9500 96.67 1 13.33"1 WchOO9 7167 51.33 63.33 51.33 56.67 40.00 61.67 76.67 , 9167 96.671 69.00": I ~~II __ ~ S6.1"·~ ~ 81. 17C 72.00" !1.J3c- 72.00 79.63" 82.50 90.9~ . __ ~J Pvalue(GeDotypeorF.nvironrilent) <0.00' LSD 5% (Geootypcor Envf..onment) --- ---- 6:456: ~~~e ~~notyp~ X .:nvifO~m~n') ~ < O.~I ) LSD SIV. (Gt-aotype X En\'ironmttlt) 20.417 CV(%) -- 17,'1 I ' L F 'II~I.:n..lltl University of Ghana http://ugspace.ug.edu.gh TABLF. of: ProportiOD of Su. or Squares for maio dr«ts aod i.DtenctioD fer p«e:eotage sprouting ror nine yellow root .ad ODe write rool cauava gC'DOtypaill JOenviro."~I:S. Sour('e or"a';alio. ; DF r Meao squam · ~butiOD to S5 . lAnotype - - - - 9 . -I-~ 0 160 ... • 12.32% ; i~\'''''''..ellt I GHotype by eavirodlDul University of Ghana http://ugspace.ug.edu.gh University of Ghana http://ugspace.ug.edu.gh ~: ProporticHI of Sum of Squares ror mai. erfeds and interat~OD ror n".bel' of' plants pcr hec:lue (or nl.e yellow root aad oae wnle rool ussavacenotypesinIOenvironme.u. Sour"Cc--efuriatioa . DF ! Mean"sq •• ITS · ContributioD to SS IG.. o 1 typ<---- ·- 9, 2.210 ... 144% : En.;. .n ...' --+1_-~-lJ-""'5.C""C41 0 ... i 35.4% waotype by clwironment 81 I 3310.,l - 19.2,... :Erro, 1197 . 2.210" 31.0' ' · : .. . ··· 5187. .f ~.005,..., OOI"aadO.OOI.". lli..b.E...l: AMMI Interltlion analysis of \lanance including the fint four interaction peA ut's for the number of plants fH'r hectare of nine , yclknt root and oae write root cassava gtnotypes lesled In 10 t'DvinMI.e.tI. Source ss MS Probllbilil) TOI~ 1408478193.8 4726436.9 95)9369458 %35726.1 Genotypes 19S6606636 22013407 I < 0.001 .... Environment 489618489.8 54402054.4 < 0.001··· GXE 81 2656511925 32197258 0.02 • lPCA I 11 1104892943 6499310.2 < 0.001·" IPCA2 15 526412121 3509414.1 0.09 !peA 3 480(24)16 369Q4178 008 lPCA4 2.'lIUm"'09 2110951.3 0.49 ~ 30554323.6 12221729 0.97 Enur 199 4545412480 2284126.9 ---------------_. .. ------------------.... •.••.••• slgIU6caatIlO.05,"-,O,OI%...sOOOI"/Q University of Ghana http://ugspace.ug.edu.gh ..... Averaze numbu or.torallt' roots per plant The numba" of storage roots per plant is shown in Table 10 The highest value of 7.107 was obtained for the genotype 01ll368, while the lowest value of 3 4J9 was recorded by Wenchi 009 The number of stonge root per plant differed highly (p ~_~ean l~~!33~ 342(HjD·~~t21M72d_34567~~7i 59~~7l'i.::: 37019: P value «;enotypt or EuvlronmeDt) <0.001 '1 ~~~I:~:~~::::~~~:~~netr) ~~~;: 1 I.SO !w. (Genot)pt X Euvironment) I'B8~.1 f cv (0/_) - - ji.~ University of Ghana http://ugspace.ug.edu.gh !A!!I&.....!: Proportion of sum of squares for main ~ff«ls and interaction for number of stor.le roots per IIrelare for nine yrllow root and one writtrOolcassaVa2l'notYI·esinlOeDvironments. I Sourceoharialion . . Muo-squlns i Contribution to SS I ' (~nOllPC' '3.06io'-**· -· + 23.06% ' [nviroD~nl 4.51 10'''' I 3396~. 23.88-;0 University of Ghana http://ugspace.ug.edu.gh IdIlL&...l!: Averaxe Dumber of storage root, per plant for nine yellow root and one write root cassava genotypt"S in 1ft environments. Environment! - _ . - - - r I Genotypes. EI - Ez - r"EJ.-- £.. Es ~- ' f.. Es t., F-; _I "ta~ 0iIiiU . 6565 6094 j 511 4233 3583 4622· 4602 4671 -7383 6112 5:1:"''''1 10// /135 . ; 4642 5786 6052 1725 4~223 3983 1857' 4.166 8561 18~1 5.'41" : O/I /3U 1.121 6 256 1635 1033 5687 6.302 8658'/,764 8188 7428 1.101' tovi:l7J ...: 4526 3 986 2.765 - 4103 4048 4292 38~l9 6.242 601~' 4.499T! !iiiliiii • 5.934 4 549 4.867 3.S!1 l416 4.667 4293 4675 6196 6342 ~s45"' 0/114/ Y 1 5.283 5090 5.014 5.790 5.228 731 I 5678 4.684 7 728 7.0845.i9s~ i 0/1/442 . : 6884 4858 4.760 5.280 7.190 4791 1 H91 4286 8784 7 193 ~ I 0/1/6/0 . 4961 4.389 6202 _6 .607 5333 4428 L 5766 481 7 6931 8 796 ~.824' 0/1/663 , 4.569 4300 2 724 2.352 5019 3W ~ 040~376 8987 VOlt S. ..2 " · WchlJtJ9 ~. ~3 58~1-, J 895 1280 3.389 4456 4944 ' 2 m 3.034 3560 3.661 3.439'· Vlean 4.920 . 4,4.87' S.062 4.I~~lii ~=4.'i7~ 4.761" ~6'19~•S. ~J4: ~ P value (Genotype or Environment) < 0.001 _/ ~b~:~~:e~:;~::-'::.~t) ~ - - . .: ~~:~ l.sD ~. ;. (;rnotypt" X Fnvironme.1) t l.tOl! @:(~ - I' I"fd<:rh' C ' '' ' II . ' r '''''' '''' I- j(1 - ----Z!'.6' University of Ghana http://ugspace.ug.edu.gh IA.IlL.E....ll: Proportioll of sum of squarn for maio efl'ects and interaction ~or •••h er of stor8,t roots per planl for nine yenow root and oae wn.e rootcalSllv.~f'Potypesi.l0uviroo ..e ats. ~: AMMI [attraction analysis of variance including the first four ' i.'endioll PCA aus for the Gumber of Itorallf' roots per ptant of nine yellow root and one "rite root tauava gCDOtypes tested in 10 1'D'''iroa.eats. 55 Probability Total IIS4.S14 Treatment 784865 Genotype 259.335 28.815 < 0.001 ... l :n\' lfonment 27.647 < 0.001 ... 276.708 3.416 !peA I 17 78239 4602 IPCA2 IS 767S4 5JJ7 < 0.001 ... • J3 3882 IPCA4 30.117 2.738 0143 Re~ldual 2S 1.645 0.62S Emx 369649 18S7 --------._------------ -- • . ••• ••• slgrufICMttMOfJS·.,OOI ' '''andOOOI· . University of Ghana http://ugspace.ug.edu.gh 4.S Ft't.Shslora~e roouyidd perbecta.re (tlh' The higheR .I.vv.!.gl: sa.,... root yield pet hectare (28 3S ton~) was obtained for genotype 0111368 and the lowest was recorded by the local check Weochi (849 tIbI) (Table 13) The average yield amons the 10 genotypes was 20 55 tIha There were highly il~mficant dIfferences (P < 0001) among the genr 24048084 121.4SS J';S nOI1~I~nlftunt . e. " : ••• · "lrUr~atOO~ •.•. OOl%andOOOI% University of Ghana http://ugspace.ug.edu.gh 4.' Frail stonilKe mob .. riabt per plut (Ill) T.bie 16 shows tht 1\ crage fresh root weight per planl Genotype Wenchi ()()9 recorded the kl'NC:SI value of 1 486 kg. while the highest value of 4 094 k1l was recorded by ~-pe 0111417 There were highly significant differences among genotypes, environmeru and genotype by environment interactioa. respectively (Table 17). Based on the acua sigmficant difference at 5%, the genotypes 0111412, 0111235 and 0111368 bdol'll to the same group of best tlenotypes (tughest fresh rOOl weight per plant) The best cm;ronmenu were E] and Ed> <:; "-8 per plant). The poorest environment was El wilh an .\~ of 1.121 Its of fresh fOOl per plant Gmotype. environment and G x E irueracl10n ac:counted for 14.7JOA. 373CJO/o &ad 17760/. of the total sum of squares respectively. (Tablo 11) Resulll of the AMMJ analysis (Table 18) showed thu the first principal component axis (PeA 1) and (he second principal c.omponent uis (PCA 2) of the inttraction captured 39930/0 and 25.69". .. of the interaction sum of squares, respectively funhermore. the meen squares for PCA I and PCA 2 were significant at P <0.001 and P'J)e 0111311 in environmentE~ while the highest sboot weiabt of 38. 25 tIba was scored for 8cnotype 0111663 in en\"ilOnment E. On the .'erage. genotypeS 0111368 and 0111663 registered lhehighestvalue and lhe Jocal check Wenchi 009 has S(:I(JI"C the lowest value of9.1' tlha The best environment was 4 while the_were E, (I03S 1Iha), E, (II SS 1Iha) and E,(119711ha). There were highly lignificam differences among genotypes, environments and genotype by environment intend. .. (Table 22). Genocype. env~ and G x E Inlcradinn contributed 19.43%, 37 .87'~ lad 19.70'10 to the toW sum of squares. r~ively (Table 22). Environmenla' inOuenccwasthemostpredommam 73 University of Ghana http://ugspace.ug.edu.gh I6JlL£..1!: Avtn;r rrub lIoraltt roec wtight (c) for oint ytllow rOOl and ont "ritf' 1"f;Kt1 cassava gtltOrypel ill to t.viro.~.tJ,. .--.-- ~---. University of Ghana http://ugspace.ug.edu.gh ~: ProporticMI ef JUDI of tqures (or .aia effects and ,interaction for uengr w~i~bt of individuJ frn:h storage root for aIDe yellow roet loci one "rite root cassau genotypes in 10 t'nvironmeots 4.9 frtshshoolwtightperplant(kJ) Value.t of the shoot weight per plant were presented in Table 23. From fhl' results the # throe main sources of variation, genotype, environment and genotype by environment Inl~ion revealedt1l8hly5ignificantdifTerences(p06 and 2006- 2007 rtspeetively The genotype, the environment and the G x E interaction for (he &boot "elsht per plant conuibuted 15.47"/• . 31 12'/t and 23 37"/. respectively to the total sum of squares 1$ pcr Table 24 7S University of Ghana http://ugspace.ug.edu.gh University of Ghana http://ugspace.ug.edu.gh ~: Proportion of 'UID of squares for main errects and i.teractioD (or .venlf fresb ,boot yidd per beet.rt for nine yellow root ••d one write root caua"a genotypes i. 10 fll,'ironments !s ..rceorvan.tion ~ J Me. .. squarn r Conlribu-'io. to 55 - \ ~typt -fg--~ 68480... 1943'1. ---1 ' t:nvironllllent 1334.82···1 )787% Gtaotypeby eO\'ironment 77.14··* 1 [;;., -~ ----mij- ~ - ~::. - - - : . ··,···$l8ftdi~1l00S". . O.OI%udO.OOI". University of Ghana http://ugspace.ug.edu.gh ~: AvtnllKt- fresh shoot weicht per plant (k&) rOt nine ydJow root and one write root cassn. ~tnofyp" i. 10 fJn'ironm,.u. ~ ------c==--- ----- : ~n~~~~ts~ =--=-: _ ~ - -~-r-=---' : ~'~~68 ;;70 ~~S6 ;~I I ~~71 I ~O . ~~07 ~i20 :'165 :'t62 :e;;~ 2411 2.91S lOS< S.964 0.122 2101 ISIS ·2124 2612- ! 21~ : 1.701 " ; S.19S 1014 : 4171 1915 3203 2107 l221 J.O ••" 1988 S.tS7 1.:!6s'2.i23 1.407 2 S60 2.895 ~.l69"' : 2040 l .ISS 06SS lO99 1.14S 2.0SI 2.1J8 11SS 2.0'l2' 2.080 1921 l130 1:,66 4.110 1.904 l S66 2314 27132.550'" r.-:-:::;-;-;----r.-;-;;-;-+2.,0.""I_t-l OS2 4884 149S 2.280 1.061 I 816 1~.Jil'" _::~ ::~; ~!~! ~!:! ~~: ~: ~: ~ :~~ ~;~! l736. ~ :~~ ~~ ~Wc;'OO9 1119 13S1 )404 2.970 I t>16 -"- l.bI6r . Mr.n-~, 2.251'- 11.711 2.19r ~4.14S· 2.'}~2~"" 1.604 1 :ffi~~~~ ~i ~~ ~ EWrck I'IW University of Ghana http://ugspace.ug.edu.gh ~: Proportiea of tum tIllQuares (or main effects aad .iDtenctioD for avenl8e (rt'S" Iitoot weigllt per p'• •' (or .ine ydlow root and one wme root cassaVII re-otYpesial0f'llvireo~nb !S O'II'~e oIVaria_u. _- h-_+M_ean-=squarf 409~ IS5 20894 . , •• . ••• slpificaat.OOS"O ,OI·~andO,OOl% University of Ghana http://ugspace.ug.edu.gh •. 13 Storage root dry yield ptrb«tar'e(tlba) Tlble)2 abo .... :- values for storqe root dry yield per hectare The general mean of storage root dry yteld for the 10 FnotYPC:S across the 10 environments was 6.28 v1la. The highest value was registend by genotypes 0111368 (8 78 tIba) while the lowest value 3.26 tIha was registered by local check. wencbi 009. Out of the ten environments 5 of them (Et.. Eo. E" Eo. and Eo) were grouped (LSD5% • 1.275 1Iha) in the fim caIejjOrY of bigh .venae dry yield. The lase catesorY of least average storage root dry yield was composed 01 t .... o environments whicb were E7 (4.80 tIha) and E. (5 .20 t/ba).The main sources of \·arlation. genotype. environment and G x E interaction were highly significant for the stor'8"rooI dry yield (fable 33). Fotthestorage_ dry yield, the.enotype.lhe Mvironment and the genotype by environment interaction accounted respectively for, :: I 1t)"I. , 21 83·A, aad 2561W. of the total sum of squares while the error contributed 31 18°'010 the same sum ofsqu&fe~ (Table 33) 4.14 Sloragerooldryweig~tperplant(ka> Storage root dry weight mean values are presented in Table 34. The mean values ranged from 0.600 kg to 1 184 kg per plant Combined anaJysisofvarianceshowed highly significant dilTerenc:e among genotypes, environrnmb but the G x E interaction wu significant at O.Oset.1eve1 ofsignificant (Table 35). LSDS% 0(0.228 kg grouped the foiklwinggeootypes into one: genetic group 0111224.0111235.0111368,0111412, OJ1I417. 0111610 and 0111661; thefoUowing were also grouped into another group' Wenchl 009. 0111371 and 01/1442 ThebeaeovironmentwuE6(1964tJha) Environment accounted for the larger proponion (42.4t%) ofthc total sumofsqu&fcs while genotype and the G x E interacuon contributed for 9.59% and IS 35% sum of University of Ghana http://ugspace.ug.edu.gh .~. I ~~ " ~ ~ F> ~ 'Il ~ I !l, 5 'Il ~ ~ g 10 ~ ~ I I I I ~ i" I ~ I I I I I .," a i Ii" c; University of Ghana http://ugspace.ug.edu.gh TABU: 33: ProportioD or ~um or aquarrs ror main t:fTecU a.d intenc:tioll ror Iloraat: root dry yield in tons per bKt.~ ror Blat: yt:Uo .. root and one write root us~av. genotypes in to environlDt:nts. Environment 92)7"' I ~ F()pe""-by-"'-",",~'-. .-..t +.,8~1+ -~1~2.2=l'="'-;',- 2S6r/. ' Error - 197 6.27 I 3128% ' . .. ; .... "pU. ...-., ;-0-01'".0 o,,,~,.~.1.~ ... O.OO;;;;,.,.%-----L-- University of Ghana http://ugspace.ug.edu.gh ~: Average storage root dry wftcbt ptr planl (kg) ror nine yellow rool and oue wrile root ca!isava ICDoCypes in 10 ~nvironments. (1/11411 !~~7_ 0434 1171 10432499 .: ~;~;;! -,--,~+-7~~"+- ~---.;-;;*~+;;.~ '011166J ' W('/t009 jIS Prob.bilil~· r",&1 577763 3123 Treatment 371640 5.386 <0.001 ••• Gena_, 24913 00)6 • En\l"lfonment !> 223.827 < 0001·" GXE 122.899 2.276 O.13S sS IPCA I 68.977 4.927 0.001 •• IPCA2 12 22.818 loo2 0.392 !PCA3 10 19.399 1.940 0.)7' lPCA4 7.116 0.889 0.854 Residual 4.588 0459 0989 En.. 116 206123 1.777 ~slg"l(teanI. ·.·· ; ··· : llgnlr)Q,n(atOO1%;OOI'\.andOOOI·o University of Ghana http://ugspace.ug.edu.gh 4.17 Br-ta-carotHe coat"1 HI !IIlonp roots per plIOI ( ..C ) Tbe values of beta carotene content ifl .ange roots per plant were reported In TaMe "2 Tbr data ofbeu c::an:uae coateat in storage root per plant ranged from 0 .92 mg up to 29.27 l1li and the aeoeraI mean wu 12.17 mg. Difference antoog genotypes was ....f i_ .........k ' of the AMMI anal>,,;' of .... beta carotene content in storaae roolS per plant. These results showed that the first principii eocapooeot axis (peA I) or lhe inleraction captured 61 .070/. oftht interaction .,. of squares in 2S.92% oftbc inleractioa degrees of freedom Among the four PeAs only peA 1 praentcd hishly 'ignificant mean squares University of Ghana http://ugspace.ug.edu.gh TABLE 42: AVfra~t beta carottne in (resh storage roots per plant (mg) (or seven yellow root casu". ~tnotypn in 10 Nviroamrau [C::Otyp0042). The highest beta carOlene content in 5lorqe roots per hectare was obtained for 01 / 1368 (98 .8 g) , folktwed by 01/1411 (90.3 8) Thete are the best genot)'pe$ for this variable. The difference amorl8 environments was highly 5i,nificant (pO.OS) The overall best en ... ironment for this charlctct ..... E. (Pokul.\c q MAP In 2006-2007) with 1394 g per hectare and the environment given the ~ mean \IOU E, (Wenchi at 9 MAP during 2006-2007) recordina 163 8 10 this study tile G X E eootribution to the aim ofsquarcs was 2111'1. compared to 25.201'. b environment and only 491% for genotypes (T1bJe 46) The error contribution to the sum of squares was 42 IS-I, The results of the AMMI analysis of beta carotene content per hoctare are shown in Table 47 The first principaJ component axis (PeA I) of the WtQI;(ioncarcun:d S9.6O'/eofthc:interactioatumofMjWlfc.in2S.92o/.ofthelnletac:tion de:srees of~l)m The lMan squares for the first principal component axis (peA 1) was slgnlftCaftluP I~~-H. ~ ! I r r o ~ i!~. "; I ~ ~ ~. ~. :lJl ~ ~ ~ ';I I I ~ ~ ! ~ I I f i ~ 11 ;0 University of Ghana http://ugspace.ug.edu.gh TABLE 46: Proportion ef Slim of Squares for ..h i err~cts and lntendio. for 8\'~nIIg~ beta uroteoe content i. fre!. Itora&e root pc:r hectart of UVfll genotypes In .8 uvirooments in Gb. .. -s;.lIruoi'nriatio~ I DF ! Meusquaru I COnIrib;ii;Ot"O-ss 1 , 0.043 ' Environments 211057.976 23450886 < 0001 ••• GXE 54 232035203 4296948 0063 N1 IPCA 1 138290853 98n918 -< 0001 ,., lPCA2 12 381n.765 3181064 0(1) lPeA3 31618084 3161808 0416 lPCA< 1416507R 1770615 0791 ReticWI 97R8422 97H 842 0974 Em" 3531S9011 . . ...... , flltfllficantaJOOS%"O.OI%and 0 001'. .. University of Ghana http://ugspace.ug.edu.gh .... , WinDia~ genotypes and mtJa-t'Dvirouttilt idutitkttioa for bd,-Clroteoe (euteRt bued OQ GGE biplot A GGF. bipkrt analysis has the ability to usess the genotypeS for their me&n perf()l"'lDlftCe and ability 00 the biplot a single-arrowed line. the average .... caled within the fl'.11~~,," lind Vt"C«: found len responsive (Weikai et al. 2(06). Environments E), EJ• r... 1-.. . ..... e. . E., and Elo fell in the sector with genotypes 0111224, 0111371 and 0111361 !-n\lfOnment h fell IR the sector with genotype OIlI23S. Environmenl E, fell in the University of Ghana http://ugspace.ug.edu.gh JCdor wlch gtrII)fVpe 01 / 1417 No environment feU in the seeton with ~notype01/1610 1.U ... PC2'"21' ...., su.,~,.. ... , ....... o ,~.O, CewuoTv·l. M·' !:J.1!.l.B.L1: \tua pc-rform.a('fO aad 'labilK)' of 'tnn YfOliow roOI cana"a .:enolypes .in. ..I I taviroamtnts for btl. carottnc concfOntration In fresh .toragt University of Ghana http://ugspace.ug.edu.gh .'~ U"I , i i ' 0 25 3D tit;, Rl A: Mf'Ka·eovironmenl ddiDed by diff~ftt&' win.i_, snftl ,~I,", root cassava genotypes tnlrd in 10 f'n"ironmtnf, for the beta urolrnt cODCf'a.rationiDltoragtroot. University of Ghana http://ugspace.ug.edu.gh "19.2 Bda-urntNt ~tHlt per ,toraJt root (me) TIl< Pel and Pe2 -,,",. which make up tile GGE ~Iou (FitIurU 9 and 10). explainod • total of '12-/. of the total vwiarion. The mean perfOrmInce and the ltability of the geaotypes forbeu. carotene content per iPdividual storage root are shown in Figure 9, The highest average value of beta CItOCene content per lIOraac root was registered for IJOOOlypo 0 111251 followed by 0111417 and 0111412. Geootype 01/1 JbS bad the low. .. value ofbm carotene concentration foUowed by 0111610'" 0111371 . The moll stable ~ for beta ",01. .. """lent pet _ root .... 01/1610 followed by 0111171 The hisblyllDllable genotype woo 0111412 followed by 0111235. aodOll1417 Fi..,.e 10 Jives a polygon view of GOB biplot sbowiQl which genotypel won in which cfwuorunems for ~ conrad per 1t0f'lr8C root, The vmcx Fnotypa ror the , heel cuotc:ne content in 9torase root were 0111235, 0111417, 0111368_ 01/1412. Two 8motype1 were found less responsive (0 1/ 1610 and01 /137l) and were located within the ~)'gon indicating thai: aonc of these two genotypes were not Ihe best in any of the test enviroameab Tbrce rncp enmonmcnls were cIe:fiud. The r. .s t was the 8enotypes 01/123S l1li1 0111417 winninS·niche made of E1• Bl, &. Ea. and E,.. The second mega ttwironment fell in the SCiC10r wilh genotypaOll1412 and 0111224 madeofrnviromMnts E~. 1:::, and E. F.nvironments ~ and F. . constituted the third mega environment with I_OIlIl68. 0111610 and 0111171 University of Ghana http://ugspace.ug.edu.gh PC, H("l H.[ 9: Mean petferwaHc aM stability ohnea )'~UOW root (usava gcaotypu in 10 eIIviroolJlcnts ror bel. urotf'llC (o_lent pt1' 'tora~ root University of Ghana http://ugspace.ug.edu.gh \ . ~ --+;_~ ,,,rol1 I i I I i I ., i -0 4 0 41 08 I ; ;' 0 pel ~: Mtp-c-DvironmtDt defined by differenl winning srvu ytUow root ussau aeaotypa 'Hted In 10 tD"ironmen', ror Iht' beu ruot,.ne (,oDtf'atptrlton~root. University of Ghana http://ugspace.ug.edu.gh 4• • '.3 ~ta-<.roteH cOIatent ~r plant (mJt) FCUre 11 shows the mran pafOf1lW'l(:e and the Slability of the genotypes for beta c:aroceue c:ooIent pel" pI&nI Gmotype 01/1224 hAd the lowell value oftbe beta-carotene OOftIcnt per plant followed by 0111610, 01/1412 and 01/1371. The highest value wu ~st.,ed for p>Otype 01/1417 (also the most ~able) followed by 0111368 and 0111235 The most unstable genotype was 0111368 followed by 0111235. and 01/1412. For thil analysis the PC I and Pe2 together explained up to 73 7% of the total vari&lion The bfplot of Fiprel2 gives. polygon view of GGE biplot showins which gen0type5 won in which environments for beta-c:arotme content per plant. The Vene)( genotypes for lbe beu.carotene conlent per plant were 0111412. 0111235; 01/1417, 01/1368, 0111610 , and 0.,1224 Oae genotype (0111371) located within the polygon wa5 found less responsive According to the Figure 12 four mega environments were defined. lbe 6rst meat eovirorunent was the geootype 0111417 winning-niche made oCE), E., EJ. E" E •. and Elo The second fell in the sector with genotypes 0111412 made of environment F~ The third mega environment was the winning niche of genorypc 0111235 and made of er\monmenl EI Environments E, and ~ constituted the founh mega environment with gCftOlype 0111368. No environment fell in the sectors "'Ih getlOl)1)C 0111224 and with genotypes 0111610 and 01/1371 University of Ghana http://ugspace.ug.edu.gh 16 24 3'2 4.0 48 56 PC1 !Hil.:.Bl.l!: Mean ptrfomlance and s.ability of.nen }tllo" root canan Kenoty~ in 10 rn\'ironmenb (or bt1a carotNt conltnl in slongt rool pn plant University of Ghana http://ugspace.ug.edu.gh I I i'~ .... G)'RE 12: !\1~.-CnviroDmtnt dtfined by different winnin2 seven yellow root cassava IUOlypn Inled in .8 tU\lironmeutJ ror "t beta carotene coaknt ia stonae met p« plaat. University of Ghana http://ugspace.ug.edu.gh 4.19.4 Beta-ul'Ote. cOilteDt per "«taft (&) Figure 13 IIhows the mean performance .nd the stability of the lenotypH for their beta c:arcxeae COI'Ilent ia storage f'OOiIS per bectare. The bi(lhest performIDce value was _rdec! Cor genon for number of storage root per pWII: for white rooc cassava geootypeS bas the Iughdegreeofmerit(O.82)re1ativetothedirectselectionfor51oragerootyield, Heneethe raunberofroot pe:rplant is an important vari.ble to be con.idered for yellow root cauava sclcd.MJn (or high root yieW. The avenge results of number of stora!otc fOOlS per plara of tlus INdy which ranged from 3.4 to 7 I was lower than the average rangcs wlter' reported by Maray. el aJ. (200 I) in a two year study of fi ve while foot cassava genotypes , In five loc.aIjons in Guinea (S 610 8 6) and ill tine aocations in Togo (5 4to. 5). ThC'!>e Figures were alio lower than the range 0(0.3 to 10.0 roots per plant reponed by Otim-. S.pe~' DI (1994) for 13 white root cassava varieties studied in Ihree districts of western The differeoce in I'AJmba' of storlge roocs per plant which was highly s.igniflcan1 (P yidd) br=Inged -. 23 .~.and lJ.'''' with agnnd meanof28.82. These roponed dry matterCOft:cm: vaklesll'eiowerwbcacomparcd withtbo!eofthe present work Kawano 61 aJ. (1987) reponed thIt root dry matter content and root fresh yield are compctina componerD aDd a negative correlltioo should arise l>et\wIeD them when the usimilationbythecropracbes~ccili.aaaodthevariabiljtyi.Ddrymatter yield becomes limited These authors added that if there is no indication of negative COfTeWKm bet\l.·een the two parameters, this sugest thIt a yield platc&u has not yet been racbcd. lD the Pfl*IDl Rudy, the COrrdatioD between these two variables was neptive aDd wgru6c:aat (pe 01/(417 for its high fresh root yield per bcctan: oombined with iu high perfQf'lD&nCe aDd stability fOr betacarotclleOODlalt in ftesbrootsper plW, For industrial U8e, it was proposed the genotype 0111368 with rugbeR performance in tiabrootyield pe:rbec:tareandhishest betaearotene content per hectare For bru:ders wbo would like to improved beta CII'OteDe content of the k»caI mealy genotypes throush crossing it was proposed to CODIider the senotype.5 0111224, 0111417 I.JIj 0111368 as parent&llines because of respectively (I) the high performance in beta carotene concentralion In a very wide ranse of enVironments, (2) hiah yield and the stability in beta carotene content per plant and (3) the highest performance In fresh root yieldandcatOlencconlC1llperhectaJ'e ConsidcriDs tbeimportanceoflhebcu.carocerc in t.J.man Ofgaoism. it wu suggested thai funherresearch works be carried OUi 10 study the genotypic differencesofbioavailability of the beta carotene content In yellow cassava and other factors affecting the Re"de beta caroIme content it was suggested to initiate research works be carried out to Sludy lhe: iroa. and zinc content of tile yellow rOOl C&.Uava genotypeS LD t.bis study it was plumed in coUaboration with Gbana Atomic Energy Cea&.re (GABe) 10 use the facilities for detenninallon of mineral component. of the yellow root casu. ... genotypes using instrumental neutron activation analysis, At each har.'est samples were ....' nl 10 (jAf.C but for various re:uoos beyond our control includiog unavailability of liquid nitrogen and lack of electricity thIr pan of the Jtudy could not be completed It will be recommended that miDeraI components of the yelLow rooc cus.ava be studied lO know nwnlytbe[lCDOtypic: variMion in iron and zane conleot University of Ghana http://ugspace.ug.edu.gh Because of the imponancc of Cassava in Ghana and the nutritKmal problems cauted by vitamin A deficiency in thecountry,itwuSI.Iggestedtblla research task rorce be Sd up - the AariwIrunI Rcoean:h hulilwa (CRI. SARI elc. ~ the Uoivcrsibes (Legon, Cape: Coast, K.wnasi etc). the centra) nutritional Labs (Noguchi) and tbe Ministry of Agrieuhure (MoFA) for SUSl&inable management of the yellow root cusaVI rool reseArch University of Ghana http://ugspace.ug.edu.gh REFERENCES Adarru.C 0 . 1957 ActivitiesofDrranisb Bollnists in Guinea 17J8·1850 TransactWnsof the HUwricaI Sociuy orGhana UI Panl Adewusi Steve R. A and Bradbury J. Howard 1993. carotenoids in Cauav• . Comparison ofOpeo-Column and HPLC Methods of Analysis J. SCI. Food Agnc 62: 315-383 Aj .. O. O. A G. O. Dixoo, and E A AkiDrinde 2001 : T.u &S>Ociotioo and path anatyJis lOr yiekt of cassava seaotYJ)eS grown In various qrocwo:o1ogies in Nigeria. In Root Crops' Tbe small prooeuor aod development of local food industries for nwket economy M. 0 Akoroda 2003. (ed) Proceedings of the eighth Triennial Symposium oftbe IntematKwaal Society of Tropical Root Crops - Africa Branch (lSTRC-AD) Pp 399-404 AkobUndu.. I O. 1980 Weed science raearch 11 In.t.emation.a1 Institute of Tropical Agricu.Jtureand re$eal'ch needs in Africa Weed Sc, . 28439-444 Akoroda M. 0 ., C gjcaJ c.ondilKms in Ivory Coast In Belen. E H. and Villanueva, M (ech.) ~ Sib Symposium International Society of Tropical Root Crops (ISTRC), Los Banos, ~na. Philippines., 1919 PhilipPIne Council for Agriculture and R. ...... Raean:h. Pp 323-329 Oicbon K. B . and B,.neh G. 1988 A New Geog1aphy of Ghana. Longman Group, UK Limiud. HatIow 70." University of Ghana http://ugspace.ug.edu.gh Dixon, AGO., R. AMedu, S K Hahn 1991. Genotyp;e !Ub;lrty and adapUb;tily. A.oalytical methods and implicationJ for cassava breedin8 for low-Input Ijpieu\ture In Ofuri F. and S K. Holm (ods). Prt.-Ims of the 9th sympo,;um of .be Intematiooal Soe;ay for Trop;c.l Root Crops (ISTRq 20 -26 0eI0ber 1991, Aeea, Gb&na pp \30·\37 [);xon, A G. 0, R. Bandyopodbyay, D. Coyae, M Fsgu_ S. B. Ferri~ R. H. .... I d'A HuPes. I Int!dbroc:hI, I. Lea. N. Mahuttgu, V. Manyoas. D. Mowb,pp173· I94 0..0.1. 1987: Pignwnls mfnlits Academic Pres&. LoDdon. Oro" 1. 1991 · P,gtWfIlS IIf wgrtkJbJ~~ Chlorophylis and carolenoids Avi : Van Nostrand Reinhold Company Inc, New York fhaen,man> V . Corey E E. Gicbulci S. T. • Oyunsa M A. • 1"""'8i I. K 1999 Carotenoid COIllents in fresh. drted and proce:s.sed sweet potalO producu. EcoI. Food Nutr. 37 455-473 Hagerumana V. Oyunga. M "-. Low I.. Nioroge S. M Gi.1uIU S .• and Kabi,. J 1999 The effecu of women farmers ' .ooption of onnge--flesbed sweet pou1OCS raising vitamin A intake in Kenya. ICRW/OMNl Research program, Research Report Series 3. International Center for Resc.uch on Women, Washington DC, 24p Hahn. S K . Ilowtand A. K., and Teny £ R 19TI Cassava breeding at UTA-In: Lakey, C L A (eel). Pro< Jrd Symp 1m Soc Trap. Roo! Crops. Ibodan, Nis. .... 2·9 Dec. 1973. nTA (imemational Inslrtute ofTropi.c.a1 Agriculture), Ib&dan, Nigeria pp 4·10 t IJhn. S K and Ktylen, J I9IS eu.va A bait food of Africa. 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