See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/323458942 Field evaluation of tomato varieties/breeding lines against tomato yellow leaf curl virus disease (TYLCV) Article  in  Pertanika Journal of Tropical Agricultural Science · February 2018 CITATIONS READS 2 290 7 authors, including: Mark Makafui Segbefia Kojo Ahiakpa University of Ghana Research Desk Consulting Ltd/Huazhong Agricultural University 5 PUBLICATIONS   12 CITATIONS    27 PUBLICATIONS   59 CITATIONS    SEE PROFILE SEE PROFILE Emmanuel Kwatei Quartey Andrew Sarkodie Appiah Ghana Atomic Energy Commission (GAEC) Ghana Atomic Energy Commission (GAEC) 25 PUBLICATIONS   67 CITATIONS    19 PUBLICATIONS   41 CITATIONS    SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Phenotypic profiles of 20 accessions of sweet potato (Ipomoea batatas L.) from the coastal savanna agroecological zone of Ghana View project Igeza App View project All content following this page was uploaded by Kojo Ahiakpa on 28 February 2018. The user has requested enhancement of the downloaded file. Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) TROPICAL AGRICULTURAL SCIENCE Journal homepage: http://www.pertanika.upm.edu.my/ Field evaluation of tomato varieties/breeding lines against tomato yellow leaf curl virus disease (TYLCV) MM Segbefia1, HM Amoatey2,3, JK Ahiakpa4*, EK Quartey3,5, AS Appiah5, J Nunoo3 and R Kusi-Adjei5 1OCP Ghana LTD, No. 9 Kwa bena Duffour Road, Airport Residential Area, Accra, Ghana 2Department of Nuclear Agriculture and Radiation Processing, Graduate School of Nuclear and Allied Sciences, University of Ghana, P. O. Box AE 1, Atomic-Accra, Ghana 3Nuclear Agriculture Research Centre, Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P. O. Box LG 80, Legon, Kwabenya-Accra, Ghana 4Research Desk Consulting Ltd., P. O. Box WY 2918, Accra, Ghana 5Biotechnology Centre, Biotechnology and Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, P. O. Box LG 80, Legon-Accra, Ghana ABSTRACT Tomato Yellow Leaf Curl Virus (TYLCV) is currently the most devastating virus of cultivated tomatoes in tropical and subtropical regions, accounting for significant yield losses in cultivated tomato in Ghana. Severe population outbreaks of the whitefly vector (Bemisia tabaci), are usually associated with high incidence of the disease. Resistance breeding is the surest solution to TYLCV in developing viable seeds for increased tomato production in Ghana. The Wild tomato (Solanum pimpinellifolium L.) is a recognised crop Wild species (CWS) with resistance genes to different diseases including the TYLCV disease and possesses good fruit quality traits in Ghana. Three (3) cultivated tomato varieties and seven breeding lines developed from crosses between the Wild tomato and three hybrids, three backcrossed lines and the Wild tomato were evaluated with their parents against TYLCV disease under local field conditions. Field appraisal of whitefly ARTICLE INFO Article history: populations, disease incidence and severity, Received: 10 June 2017 Accepted: 08 November 2017 agronomic and yield characteristics of E-mail addresses: the tomato varieties/breeding lines were marcaphy@gmail.com (MM Segbefia), hmamoatey@yahoo.com (HM Amoatey), undertaken to hasten selection of tolerant/ jnckay@gmail.com (JK Ahiakpa), emmaquart@yahoo.com (EK Quartey), resistant varieties or breeding lines in the andysark2000@gmail.com (AS Appiah), jnunoo@gmail.com (J Nunoo), breeding programme. Wild tomato (ISSAP kusiadjei@yahoo.co.uk (R Kusi-Adjei) = 0.31 and ISSDP = 0.76) and Woso (ISSAP * Corresponding author ISSN: 1511-3701 © Universiti Putra Malaysia Press MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei = 1.90 and ISSDP = 2.27) recorded the least TYLCV-causing Begomoviruses were and highest average symptom severity on detected and reported from Akumadan all plants (ISSAP) and diseased plants only and Kumasi, the major tomato producing (ISSDP); while the least and highest disease communities in the country (Osei, Akromah, incidence was recorded by the Wild tomato Shilh, & Green, 2008, p. 1585). Production (11.10%) and Roma (43.05%). Roma which losses vary from very dramatic to mild with recorded the highest population of whiteflies devastating yields loss in the rainy season in the dry season also exhibited the highest (Osei et al., 2010, pp. 315-323; Horna symptom severity on all plants as well as et al., 2006, p. 27). Whitefly populations diseased plants during the study period. and diseases in the dry season are usually There was a significant symptom relapse in severe during the dry season, especially Wild tomato and Woso x Wild in 6-8 WAT with relatively higher incidence of Bemisia for both ISSAP and ISSDP. Number of fruits tabaci from cassava fields in the dry season per plant, ISSAP and ISSDP were positively (Appiah et al., 2012, pp.31-37). This and/or inversely correlated (r = 0.98, 0.93, variation in whitefly population has been -0.83) with average whitefly count, percent attributed to differences in temperature and disease incidence and yield (t/ha). relative humidity (Triparthi & Varma, 2002, p.476). Keywords: Backcross, Geminiviruses, varieties/ Most commercial tomato varieties have breeding lines, Ghana, Tomato, TYLCVD, resistance been found to be completely susceptible to breeding TYLCV, compelling breeders to screen Wild tomato accessions and some commercial INTRODUCTION varieties for potential resistance genes Tomato yellow leaf curl virus (TYLCV) (Pilowsky & Cohen, 2000, pp. 351-353). disease, caused by geminiviruses and Breeding for resistance to TYLCV in transmitted by whitefly (Bemisia tabaci cultivated tomato varieties appears to Genn.), has become a major problem in be the most ideal control measure for tomato cultivation globally, particularly the virus (Pico, Diez, & Nuez, 1999, in the tropics and subtropics (Czosnek & p.1008; Osei et al., 2008, p.1585; Horna Laterrot, 1990, pp.1-6; Moriones & Navas- et al., 2006, p.31). Efforts have been Castillos, 2000, pp.123-124; Moriones, initiated to introgress resistance genes Amo, Accotto, Noms, & Cavallarin, 1993, from Solanum pimpinellifolium into some p. 953; Bellotti & Arias, 2001, pp.813-824). commercial varieties/breeding lines in In Ghana, TYLCV disease is reported to Ghana (Quartey, 2010, p.173; Nunoo, 2010, be widespread, accounting for severe yield pp.87-105). Field evaluation is essential to losses (Horna, Smale, & Falck-Zepeda, identify resistant plants after introgression 2006, p. 23; Osei, Akromah, Shih, & Green, of resistance gene from resistant plants. 2010, pp. 315-323). Three new distinct Field evaluation of resistance in some 424 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato against TYLCV Disease tomato varieties/breeding lines has been Nuclear Agriculture Research Institute widely used for primary appraisal of (BNARI) of the Ghana Atomic Energy resistant lines (Osei et al., 2010, pp. 315- Commission (GAEC), Kwabenya, Accra. 323; Lapidot & Friedmann, 2002, p.127). The experimental field is located at latitude Under natural field conditions, spontaneous 05°40’N and longitude 0°13’W, at an whitefly inoculation occurs, inducing severe elevation of 76 m above sea level within the TYLCV symptoms, especially during Coastal Savannah Agro-Ecological Zone. high whiteflies populations in the field. A The soil at the site is the Nyigbenya-Haatso number of breeding lines including three series, which is a typically well-drained newly generated backcross lines (BC1) savannah Ochrosol (Ferric Acrisol) derived were developed and three of these breeding from quartzite schist (FAO/UNESCO, lines and their parents, together with their 1994, p.146). The maximum and minimum respective first backcross (BC1) generations average temperatures for the study period and a local accession of the Wild tomato were 30.7 and 23.2 oC respectively with (S. pimpinellifolium) were evaluated in the a mean annual rainfall of 220 mm (Local field for their resistance to TYLCV disease. Weather Station, 2013). The objective of this study was to identify TYLCV resistant/tolerant varieties/breeding Experimental Material lines among 10 breeding lines of tomato. Seeds of three tomato varieties, six breeding lines and a landrace (Wild) were raised in MATERIALS AND METHODS a nursery and seedlings transplanted to Study Area the field for evaluation in the field against The experiment was conducted at the tomato yellow leaf curl virus disease research farm of the Biotechnology and (TYLCVD) (Table 1). Table 1 Identities and characteristics of tomato varieties/breeding lines used in the study Varieties/Breeding Lines Status Pedigree Growth habit S. pimpinellifolium Wild - Indeterminate Wosowoso Local - Determinate Cherry Red Exotic - Determinate Roma Exotic - Determinate Hyb-1 Hybrid Woso x Wild Semi-indeterminate Hyb-2 Hybrid Roma x Wild Semi-indeterminate Hyb-3 Hybrid C-Red x Wild Semi-indeterminate BC-1 Backcross Woso x (Woso x Wild) Semi-indeterminate BC-2 Backcross Roma x (Roma x Wild) Semi-indeterminate BC-3 Backcross C-Red x (C-red x Wild) Semi-indeterminate Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) 425 MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei Experimental Design and Field on five broadly expanded leaves that were Management Practices randomly selected on each of the 1 sample Seedlings were raised in trays filled with a plants. Counting was started 2 WAT (after mixture of topsoil, cow dung and coconut transplanting) and continued weekly for husk in the ratio 3:1:1 in a screen house. At seven weeks. Leaves were gently turned 28 days after sowing (DAS) when 3-4 leaves with little or no disturbance of the whiteflies were fully expanded, the seedlings were and their number on the adaxial side of each transplanted to the field. The Randomised leaf were counted. This was done early Complete Block Design (RCBD) was used morning (6:00am - 7:30am) before sunrise with four replications. A plot size of 3.2 m x to avoid whiteflies from being too active 3.6 m with a planting distance of 80 cm x 60 when the sun rises. cm was used for all varieties/breeding lines. Each plot contained 24 plants out of which Disease Incidence and Symptom Severity. ten (10) inner-rowed plants were randomly Symptoms of TYLCV on the 10 sampled selected and tagged for data collection plants of each of the 10 tomato varieties/ on all parameters studied. Agronomic breeding lines were observed and scored. A practices such as watering, mulching and five-point scale adapted from Friedmann, fertilisation were undertaken. Watering was Lapidot, Cohen and Pilowsky (1998, pp. done twice daily for the first two weeks after 1004-1007) was used to score symptom transplanting (2 WAT) and subsequently severity at 2, 4, 6 and 8 weeks after reduced to once daily using a watering can. transplanting (WAT). The scoring scales The NPK (15-15-15) fertiliser was applied were: 0 = No visible symptoms, 1 = Slight two weeks after transplanting at 250 kg yellowing of margins of apical leaflets, 2 = ha-1 (Osei et al., 2010, pp. 315-323). Hand Moderate yellowing and slight curling of weeding was done frequently to control leaflet tips, 3 = Extensive leaf yellowing, weeds. To avoid bias in data collection, curling and cupping with some reduction in pests and diseases were not controlled. leaf size, 4 = Very severe stunting of plant and leaf yellowing, pronounced cupping and Data Collection curling of leaves (Plate 1 and 2). The disease incidence (DI) (number of symptomatic Whitefly Population Survey. A weekly plants as per the number of plants on each count of whitefly populations was done plot) was also recorded at 2, 4, 6 and 8 WAT. 426 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato Varieties/Breeding Lines for Resistance to TYLCV Disease 151 and curling of leaves (Plate 1 and 2). The disease incidence (DI) (number of symptomatic plants 152 as per the number of plants on each plot) was also recorded at 2, 4, 6 and 8 WAT. 153 Field Evaluation of Tomato against TYLCV Disease 154 Plate1 515. TomatPol aletea v1e. sT sohmoawtoi nlgea vaersy sihnogw dineg rveaersy ionfg s dyemgpreteosm o fs esvyemrpittyo mfr osemv eTriYtyL fCroVm i nTfYeLctCioVn . Symptom scoring scale: 0-4 according to Friedmann et al. (1998) 156 infection . Symptom scoring scale: 0-4 according to Friedmann et al. (1998). Sev1e5r7i ty of the symptoms was estimated Agronomic Evaluation and Yield usin1g58 t heS feoverrmityu olfa t haed svymanptcoemds wbays eNstijmoactked aunsidng thCe fhoramrualac atdevrainscteidc bsy oNfjo 1ck0 a nTdo Nmdiap t(2o0 0V7a). r ieties/ Ndi1p5 9( 2007). Breeding Li n4 e s . T h 4e f o l l o w i n g d a t a was collected on tagged plants of the 10 160 (A) Index of severity of symptoms based on all plants (ISSAP) = (∑ (SXs) / ∑ (Xs)) (A) Index of severity of symptoms based on varieties/breeding lines during the field 1 6 1 4 4 t r i a l u s i n g D Se=s0c r i p t oSr= 0L ist for tomato from all p1l6a2n tsW (IhSerSe ASP )is =se v(e∑ri ty(S cXlasss) ( 0/ –∑ 4 )( Xs)) the International Plant Genetic Resources 1 6 3 X i s t h e n u m b e r o fS p=la0n t s g i v i n Sg =th0e score S, and IAnPs tiist aullt ep la(nIPts.G R I, 1991). Data was taken on Where S is severity class (0 – 4) number of days to 50% flowering; number 164 X is the number of plants giving the score of days to maturity; plant height; number 165 S, and AP is all plants. and weight of fruits per plant and yield per 166 hectare (t/ha) was estimated. (B) Index of severity of symptoms based on diseased plants only. Statistical Analyses 4 4 Statistical analyses on all studied parameters (ISSDP) = (∑ (SXs) / (∑ (Xs)) were performed using GenStat statistical S=1 S=1 package software (Payne et al., 2007; Where DP = diseased plants only ver. 12.0), Statgraphics (2010; Plus XV.I) and Microsoft Excel (ver. 2010). Mean (C) Percent disease incidence was calculated of number of whiteflies, fruit number per as: plant, ISSAP and ISSDP were square root 4 4 transformed [square root of (x + 0.5)] DI % = 100 ((∑ (SXs) / (∑ (Xs)) whereas means of percent disease incidence n = 0 n = 0 (DI) were arcsine transformed before Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) 427 MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei performing ANOVA. Pearson correlation no significant differences were observed analysis was performed on disease-related between mean whitefly counts from 2 parameters of the varieties/breeding lines WAT to 5 WAT and between 6 WAT and studied. 7 WAT. However, a significant reduction was observed at 8 WAT. No significant RESULTS differences were recorded between the Whitefly Populations on 10 Tomato average weekly whitefly counts over the Varieties and Breeding Lines whole survey period for Woso (Tab 2). There were relatively higher numbers of The mean number of whiteflies counted in whiteflies in the early stages of the survey. Roma, Wosowoso, Cherry Red and Woso x Wild tomato recorded the lowest whitefly WW was relatively higher compared with count throughout the study period. Roma x RW and Wild tomato (Table 2). Generally, fewer whitefly numbers were Average whitefly count showed significant recorded in both the hybrid and backcross differences (p ≤ 0.05) among the 10 lines in comparison to the parental lines. varieties/breeding lines (Figure 1). At 2 The highest whitefly number was recorded WAT, all tomato varieties/breeding lines at 2 WAT where significant differences were had relatively high whitefly populations observed in the various varieties/breeding but decreased gradually by 3 WAT except lines. At 3 WAT, Woso x Wild, Woso x WW, Woso and Cherry Red. Whitefly numbers Cherry Red, Cherry Red x Wild, Cherry increased in 4 WAT for all varieties/breeding Red x CRW did not show any significant lines after which it fluctuated till 6 WAT. differences in whitefly numbers. There were However, there was a reduction in whitefly however, significant differences in whitefly counts at 7WAT with the lowest recorded numbers at 2,4,5,7 and 8 WAT. Significant for all the tomato varieties/breeding lines difference in weekly whitefly counts were at 8 WAT. In general, whitefly preference observed in all varieties/breeding lines for all the varieties/breeding lines was except Roma and Wosowoso. There were observed during the seven weeks of survey. however, no significant difference between The highest mean of whiteflies was found the weekly whitefly counts in Roma from 2 on Roma (49.08), whilst Wild tomato had WAT-5 WAT and Wosowoso from 3 WAT-8 the least (19.58). In the Roma variety, WAT (% CV: 11.76-15.75). 428 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato against TYLCV Disease Table 2 Variation in average whitefly count with time on tomato varieties/breeding lines Varieties/ Weekly Whitefly Counts Breeding 2 WAT 3 WAT 4 WAT 5 WAT 6 WAT 7 WAT 8 WAT Mean Lines Wild 19.58e 19.23c 19.90e 21.00d 21.38e 20.03f 14.65e 19.39d Woso 43.75ab 44.98a 46.28a 44.70a 45.56a 40.08a 32.15a 42.50a C-Red 30.33cd 30.63b 34.13bcd 34.78b 34.98bc 33.08bc 20.15c 31.15b Roma 49.08a 44.03a 45.80a 47.43a 43.80ab 37.75ab 26.80b 42.10a Hyb-1 35.80bcd 31.03b 30.88bcd 29.68bc 30.63cd 29.60cd 17.30cde 29.27bc Hyb-2 28.23de 27.35b 29.23bcd 29.98bc 29.95cd 28.50cd 20.18c 27.63bc Hyb-3 36.30bcd 30.90b 35.28bc 34.25b 28.53cde 27.55cde 21.05c 30.55b BC-1 40.88abc 31.25b 37.50ab 31.90bc 32.13cd 28.00cde 16.22de 31.12b BC-2 28.75de 25.23bc 26.85d 27.78c 26.30de 22.93ef 15.80de 24.80cd BC-3 31.23bcd 28.55b 27.38cd 27.83c 28.39cde 25.18de 19.55cd 26.87bc CV% 15.75 14.05 14.48 12.71 13.72 11.76 13.58 15.75 Means in the same column and row followed by the same letter are not significantly different (p ≤ 0.05) Disease Incidence of TYLCV on 10 average percent disease incidences (43.1% TomatoF Vielda Ervailueattioine osf /TBomartoe Veardietiiens/Bgre eLdinign Lieness for Resistance to TYLaCVn Ddis e3ase0 .5% respectively) whereas the lowest Ge2n2e5 ralleyv,a lduaitsieona spee riiondc itidlle 8nWceA Twas observed disease incidence (11%) was recorded by when the highest incidence was recorded. The Roma and Woso on all the tomato varieties/breeding lines Wild tomato. All varieties/breeding lines 226 recorded the highest average percent disease inciden from 4-8WAT (Figure 1). Disease incidence re cceos r(d43e.d1% n oan idn 3c0id.5e%n rceesp oefc tdiviesley)a wseh earte aasl l or less for2 a27ll thteh ev laorwieestti edsis/ebarsee eindciindegn clien (e1s1 %in) cwraesa rseecdor dedt hbayn W 5i%ld taotm 2atWo. AATll avnardie tiinesc/brereaesdeindg glirnaeds ually to du2r2i8n g trehceor deevd anlou iantciidoennc ep eofr idoisdea stei lalt 8alWl oAr Tles s th8aWn A5%T aet x2cWeApTt Ranodm inac r(eFasiegdu grrea d1u)a lwly htoe re 20% when the highest incidence was recorded. disease severity was recorded at 2 WAT.229 8WAT except Roma (Figure 1) where 20% disease severity was recorded at 2 WAT. The Roma and Woso recorded the highest 230 70.00 60.00 Roma 50.00 Roma x Wild Roma x Rw 40.00 Woso 30.00 Woso x Wild 20.00 Woso x Ww Cherry red 10.00 Cherry red x Wild 0.00 Cherry red x CRW week 2 week 4 week6 week8 Week After Transplanting (WAT) Wild 231 Figure 1. Average Disease Incidence on Tomato Varieties/Breeding Lines Across 8WAT 232 Figure 1 . Average Disease Incidence on Tomato Varieties/Breeding Lines Across 8WAT . 233 234 Symptom Severity of TYPeLrtCanVik ao Jn. T1r0o pT. Aomgriac.t oS cVi. a4r1i (e1t)i:e 4s2/B3 r- e4e4d0 i(n2g01 L8)ines 429 235 In general, symptom severity increased from 2-8WAT for both ISSAP and ISSDP in all the 236 varieties/breeding lines. The Wosowoso gave the highest score in terms of ISSAP and ISSDP (1.9 237 and 2.27) respectively. Roma recorded the highest symptom severity for ISSAP and ISSDP over 238 the entire study period (Table 3) whilst Wild tomato had the lowest ISSAP and ISSDP values. 239 Wild tomato, Woso x Ww, Roma x Rw, Roma x Wild did not show any symptoms at all. 240 Furthermore, all the backcross lines expressed only mild symptoms throughout the period except Disease Incidence (DI) % MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei Symptom Severity of TYLCV on 10 symptoms throughout the period except Tomato Varieties/Breeding Lines Roma x Wild which recorded 1.23 ISSAP In general, symptom severity increased from at 8WAT. All the F3 hybrid lines expressed 2-8WAT for both ISSAP and ISSDP in all the mild symptoms (ISSDP<2) during the study varieties/breeding lines. The Wosowoso period, compared with the parental lines gave the highest score in terms of ISSAP (Table 3). The lowest ISSAP and diseased and ISSDP (1.9 and 2.27) respectively. Roma ISSDP were observed in Wild tomato, recorded the highest symptom severity for and Woso x WW. There were, however, ISSAP and ISSDP over the entire study period symptom reversion in Wild tomato and (Table 3) whilst Wild tomato had the lowest Woso x Wild at 6 and 8 WAT. Differences ISSAP and ISSDP values. Wild tomato, Woso among the 10 varieties and breeding lines x Ww, Roma x Rw, Roma x Wild did not with respect to ISSAP and ISSDP were highly show any symptoms at all. Furthermore, significant (p ≤ 0.05). all the backcross lines expressed only mild Table 3 Variation in TYLCV symptom severity with time on 10 tomato varieties/breeding lines Varieties/Breeding Disease Symptom Severity (%) Lines ISSAP ISSDP 2WAT 4WAT 6WAT 8WAT Mean 2WAT 4WAT 6WAT 8WAT Mean Wild 0.00b 0.20cd 0.58e 0.48d 0.31b 0.00b 0.63c 1.26de 1.15c 0.76b Roma 0.53a 1.33a 2.68a 3.08a 1.42a 1.25a 1.98a 2.77a 3.08a 1.63a Wosowoso 0.03b 1.05ab 2.13ab 2.48a 1.90ab 0.25b 1.60ab 2.21ab 2.48a 2.27a Cherry red 0.00b 0.65abc 1.15cd 1.35b 0.79ab 0.00b 1.44ab 1.60cd 1.49bc 1.13ab Roma x Wild 0.00b 0.45bcd 1.08cde 1.38b 0.56ab 0.00b 1.20abc 1.52cde 1.53bc 1.10ab Woso x Wild 0.03b 0.35bcd 0.75de 1.10bc 0.73ab 0.25b 1.15abc 1.44cde 1.56bc 1.06ab Cherry red x Wild 0.08b 0.40bcd 1.50bc 1.45b 0.86ab 0.25b 0.94abc 1.83bc 1.70b 1.18ab Roma x RW 0.00b 0.20cd 0.65e 1.23bc 0.48b 0.00b 0.75bc 1.12e 1.66bc 0.78ab Woso x WW 0.00b 0.18d 0.95cde 0.78cd 0.52b 0.00b 0.56c 1.33de 1.22bc 0.88b Cherry red x CRW 0.13b 0.33cd 0.75de 0.85bcd 0.51ab 0.25b 0.90abc 1.41cde 1.41bc 0.99ab CV% 217.19 64.87 30.54 31.01 61.95 203.62 49.03 17.05 18.54 48.34 CV = coefficient of variation, ISSAP = index of symptoms severity based on all plants only, ISSDP = index of symptoms severity based on diseased plants only, WAT = weeks of transplanting 430 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato Varieties/Breeding Lines for Resistance to TYLCV Disease Field Evaluation of Tomato against TYLCV Disease 250 Plate 2. Variation in Leaf Symptoms of TYLCD among Ten Tomato Varieties/Breeding Lines in the Field. (A2)5 R1 omPlaat,e ( B2. )V Raroiamtioan xin W Leiladf ,S (yCm)p tRomosm oaf TxY RLCwD, (aDmo)n Wg Toesno wToomsaoto, (VEar)i eWtieos/sBor exed Wingi lLdi,n e(sF )in W thoe sFoi exld .W (Aw) ,R (oGma), C(Bh) erry red2,5 2( H)R oCmha exr Wryil dR, (eCd) Rxo mWa xi lRdw, , ((ID)) CWhoseowrroyso ,R (Ee)d W xo sCo xR WWild, , ((JF)) WWosiol dx Wtowm, (aGt)o Cherry red, (H) Cherry Red x Wild, (I) Cherry Red x 253 CRW, (J) Wild tomato. Agronomic Characteristics (WAT) represent average days to first, 50% Days to Flowering, Fruit Maturity, Plant flowering and 50% maturity respectively. Height (WAT) and Yield. Among the 10 Woso recorded the highest plant height at varieties/breeding lines evaluated in the dry first flowering (30.6 cm), Cherry red for 50 season, differences in the mean number of % flowering (47.85 cm) and Cherry red x days to first flowering and 50% flowering CRW for 50 % maturity (91.75 cm) (Table were highly significant (p ≤ 0.05) for Roma 4). The least plant height at first flowering, x RW, Woso, Cherry Red and Cherry Red 50% flowering and 50% maturity were x CRW. Differences in the mean number of recorded in Wild tomato (20.4, 32.94 and days to first fruit maturity and 50% maturity 67.23 cm) respectively. The differences were also highly significant (p ≤ 0.05) for among mean plant heights of the varieties/ all varieties/breeding lines except Roma and breeding lines were highly significant (p ≤ Roma x RW (Table 4). In the dry season, 0.05). Yield was determined by the number Cherry red was the first to flower (41.25 of fruits harvested per plant, average fruit days) but Cherry red x Wild was the first to weight per plant and total yield extrapolated attain fruit maturity (79.75 days after sowing as tonnes/ha (Table 4). In general, Roma x seed at nursery) while Roma was the last Rw breeding line attained the highest fruit to flower (47 days) and mature (98 days). yield in terms of all yield components. Variations were observed in plant height There were highly significant differences recorded on the 10 tomato varieties/breeding (p ≤ 0.05) among the tomato varieties/ lines. Generally, plant height increased breeding lines for average number of fruits with age for all the 10 varieties/breeding per plant and average fruit weight per plant/ lines (Table 4). Average plant height at two, (g) or average number of fruits per plant and four and eight weeks after transplanting yield (t/ha) (Table 4). The highest number Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) 431 MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei of fruits per plant, average fruit weight (g) of fruits per plant, average fruit weight (g) and total fruit yield (t/ha) were achieved in and total fruit yield (t/ha) were achieved Wild tomato (40.55), Woso (119.26 g) and in Roma (0.7), Wild tomato (11.10 g) and Roma x Rw (48.49 t/ha) respectively at the Roma (1.76 t/ha) respectively (Table 4). end of the growing period. The least number Table 4 Days to flowering, fruit maturity, plant height 8 WAT and yield among the 10 varieties/breeding lines Varieties/ Days to Flowering and Fruit Maturity Plant Height of the Tomato Lines over 8WAT Yield Breeding DFFl FpFl DFF FpFr 2 WAT 4 WAT 6 WAT 8 WAT Mean AFP AFWtP FY (t/ha) Lines (g) Wild 44.75abc 50.75abc 81.50ab 90.00bc 20.40d 32.94c 47.18b 67.23d 41.93d 40.55a 2.78e 2.73 x 10-6e Roma 47.00a 56.50a 98.00a 114.50a 23.43cd 34.38bc 57.35ab 69.58cd 46.18ed 0.70d 13.72b 13.50 x 10-6b Wosowoso 42.75bc 55.50ab 93.75ab 103.00ab 30.60a 45.35a 67.38a 86.08abc 57.35b 6.15cd 29.82a 29.35 x 10-6a Cherry red 41.25c 49.50bc 88.00ab 100.00ab 29.50ab 47.85a 69.75a 89.00ab 59.03a 17.65abc 13.03b 12.82 x 10-6b Roma x 46.00ab 55.50ab 90.00ab 98.25ab 29.50ab 41.40ab 67.20a 88.33ab 56.61b 24.63abc 4.40de 4.33 x 10-6de Wild Woso x 44.50abc 55.75ab 93.50ab 102.00ab 30.00ab 39.90abc 67.53a 84.90abc 55.58b 14.95bc 7.85c 7.72 x 10-6c Wild Cherry red 43.50abc 51.75abc 79.75b 88.50c 29.10ab 42.70a 65.70a 90.90ab 57.10b 27.64ab 4.59de 4.52 x 10-6de x Wild Roma x 42.75bc 51.25abc 90.00ab 107.50ab 25.18bcd 34.65bc 55.88ab 73.98bcd 47.42e 28.98abc 8.36c 8.23 x 10-6c Rw Woso x 43.50abc 52.50abc 87.25ab 95.25bc 26.20bcd 41.33ab 60.78ab 79.15abcd 51.86d 15.52bc 9.18c 9.04 x 10-6c Ww Cherry red 42.00bc 49.00c 83.00ab 97.75ab 23.08cd 42.15ab 62.55ab 91.75a 54.88c 10.53cd 7.25cd 7.14 x 10-6cd x CRW CV (%) 3.51 4.42 7.06 6.95 17.68 16.74 19.55 16.49 42.18 53.10 76.05 76.05 Means in the same column followed by the same letter are not significantly different (p ≤ 0.05). DFFl = days to first flowering; FpFl = days to 50% flowering; CV = coefficient of variation; DFFM = days to first fruiting; FpFr = days to 50% fruiting; AFP = average fruits per plant; AFWtP = average fruit weight per plant (g); FY = fruit yield (ton/ha). Relationship between Disease Incidence, average whitefly count showed very high Symptom Severity, Plant Height and negative correlation with fruit yield (t/ha). Whitefly Count among the 10 Tomato Percent disease incidence, disease severity Varieties/Breeding Lines for all plants (ISSAP) and disease severity Generally, all the traits measured showed for diseased plants (ISSDP) were moderately very low correlation with fruit yield (t/ negatively correlated while average whitefly ha) except fruit number per plant which count showed negative correlation with exhibited low correlation with yield (t/ha) number of fruits per plant. Furthermore, (Table 5). Disease severity for all plants average whitefly count, percent disease (ISSAP), disease severity for diseased plants incidence and disease severity (ISSAP) (ISS ), average % disease incidence and showed very low positive correlation. DP 432 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato against TYLCV Disease With regards to ISSDP, average whitefly ISSDP. Again, average whitefly count showed count showed high positive correlation (r = very high positive correlation (r = 0.93; r = 0.89), percent disease incidence moderately 0.74) with disease severity (ISSAP). Average correlating with ISSDP (r = 0.67) while ISSAP whitefly count was highly correlated (r = showed very high correlation (r = 0.98) with 0.86) with average disease incidence. Table 5 Correlation co-efficients of disease-related parameters on 10 tomato varieties/breeding lines Traits Average % disease ISSDP Fruit/ plant Fruit yield whitefly count incidence (t/ha) Average whitefly count Percent disease incidence 0.86** ISSAP 0.93*** 0.74** ISSDP 0.89*** 0.67* 0.98*** Fruit/plant -0.83** -0.64* -0.64* -0.61* Fruit yield (t/ha) -0.18 -0.18 -0.03 -0.03 0.36 * = significant (P ≤ 0.05); ** = very significant (P ≤ 0.001); *** = highly significant (P ≤ 0.0001) computed using standard linear Pearson correlation DISCUSSION preference for Roma, Cherry red, Wosowoso The whitefly life-cycle progresses from egg and Woso x WW varieties/breeding lines. to adult emergence, governed mainly by This has led to higher disease incidences temperature (Triparthi & Varma, 2002, p. and invariably higher disease severity for 473-478). In warm climates, the life cycle these varieties/breeding lines. Whitefly takes approximately three weeks, but it may preference for specific varieties/breeding take up to two months under cool conditions lines does not necessarily lead to incidence (Triparthi & Varma, 2002, p. 473-478) with and severity of TYLCV disease as the no adult emergence occurring when the feeding habits of whiteflies predispose the temperature drops below 17°C (Czosnek, plant to several other infections other than 2007, pp. 329-342). Generally, whitefly TYLCV. However, the confirmation of populations on the leaves of the tomato are TYLCV in these varieties/breeding lines more in the dry (hot) season than in the rainy earlier by TAS-ELISA and PCR (Segbefia, (cool) seasons (Canto, Aranda, & Fereres, et al., 2015, pp. 17-24) shows that the 2009, pp. 884-894). Thus, it is important disease was transmitted by whiteflies. This to assess disease incidence severity in the supports previous observations made by dry season where abundance of whitefly Brown, Costa and Laemmlen (1992, p. populations ar expected as reported on 426); Schuster, Mueller, Kring, & Priece cassava by Appiah et al. (2012, pp.31-37). (1990, pp. 1618-620) and Asare-Bediako, The study revealed that whiteflies had high Wonkyi, van der Puije, Amenorpe and Osei Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) 433 MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei (2017, pp. 373-378) that direct crop damage and ‘enviro-climatic’ conditions (Lapidot et occurs when whiteflies feed in plant phloem, al., 2000, pp. 31 7-321; Pico, Diez, & Nuez., remove plant sap, excrete honeydew, 1998, pp. 259-271). In this study, the three which promotes sooty moulds interfering backcrossed lines (Roma x RW, Woso x WW with photosynthesis, and thus, reducing and Cherry Red x CRW) exhibited mild plant vigour. Additionally, higher whitefly disease symptom severity throughout the numbers were recorded at the early growth study period. These were comparable with stages of the plant and reduced gradually the Wild tomato (donor parent for TYLCV towards the end. This shows preference by resistance genes), and showed significant whiteflies for younger leaves at two or four improvements in levels recorded for the weeks after transplanting (WAT) than leaves three adapted parents (Roma, Wosowoso of matured plants. and Cherry Red) used as recurrent parents Furthermore, the Wild tomato had the in the backcrosses (Segbefia et al., 2015, lowest whitefly populations compared with pp. 17-24). other varieties/breeding lines throughout The resistance obtained using one the study period. This may be attributed to screening approach may not be equivalent resistance-related factors such as small leaf to that obtained using another approach. size, smell and /or other physical barriers. Thus, a comparison of the use of leaf discs Bellotti & Arias (2001, pp. 813-824) reported and whole plants in screening for resistance that in tomato, non-preference of some indicated that although leaf disc assays were varieties by whiteflies is due to physical able to discriminate between immune and barriers, such as waxy or thick cuticles or susceptible varieties/breeding lines, they the presence of specialised trichomes that were not able to “discriminate between inhibit whiteflies from settling and feeding sensitive and tolerant plants which support on leaves. The immediate manifestation of a virus replication and cell-to-cell spread but pathogen infecting a plant is the expression not its long-distance movement” (Czosnek, of disease symptoms. The TYLCV-induced et al., 1993, pp. 995-1005). In this study, symptoms usually appear within 2–3 all the varieties/breeding lines, exhibited a weeks after inoculation (Czosnek, 2007, range of TYLCVD leaf symptoms including p. 339). Incidence of TYLCVD on tomato yellowing, curling and reduced leaf size plants is characterised by varied symptoms in the field during the dry season. Based including upward/downward leaf curling, on symptomatology alone, there were no yellowing of young upper leaves, reduced sign of resistance among the cultivated leaf size, stunting of plants, reduced fruit commercial varieties to TYLCVD. This yield (fruit size and number) and death is consistent with reports by Pilowsky of plants. Symptom expression, however, and Cohen (2000, pp. 351-353); and Pico, varies with viral strain, tomato varieties/ Diez and Nuez (1999, pp. 1006-1012). breeding lines, plant age at time of infection Among the F3 hybrid lines, Roma x Wild 434 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato against TYLCV Disease and Cherry Red x Wild proved to be has not been transferred to the backcrosses. slightly susceptible. On the other hand, Differences in plant height among the 10 the backcross lines had some level of varieties/breeding lines were not significant resistance introgressed into them after the (p ≤ 0.05). All the commercial varieties first generation of backcross. The TYLCV showed determinate growth pattern whereas disease symptom development generally the F3 hybrid lines and backcross lines began two weeks after transplanting to the showed semi-determinate growth pattern field. However, most varieties/breeding similar to the Wild tomato. Flowering lines recorded no symptoms except Roma and maturity were generally earlier in and Wosowoso. Symptom development and the backcrossed lines except Roma x RW severity continued till eight (8) weeks after comparable to the Wild tomato. Though, the transplanting, where the highest severity F3 hybrid lines are early maturing which is a was attained. desirable trait, they grow tall quickly which Symptom reversal was observed in requires constant pruning and staking. The Wild tomato and Woso x Wild in 6 and 8 parental varieties which are determinate WAT culminating in lower ISSAP and ISSDP. and comparatively shorter require no This may be a good indication of resistance staking which is an indication that they in these lines, corroborating the report have been improved upon over the years by Czosnek (2007, p.332) that symptoms and are suitable for commercial cultivation. in resistant plants tend to increase with However, their fruits easily touch the ground time and then decrease, unlike those of at maturity making them susceptible to susceptible plants which normally increase attack by pests. The backcross lines on over time and then plateaus. This study the other hand, have two main advantages has confirmed the successful transfer of which are earliness to maturity and a longer resistant genes from the F3 breeding lines harvesting period (semi-determinate), (Roma x Wild, Woso x Wild and Cherry red a trait desired by local farmers. Further x Wild) to the backcrossed lines (Roma x improvement of these backcross lines would RW, Woso x WW and Cherry Red x CRW). make them acceptable to local farmers. All the breeding lines recorded low disease The relevance of TYLCV resistance symptoms; conversely, the backcrosses emanates from its effect on total yield and recorded much lower or delayed symptoms, yield components, relative to uninfected indicating that the transfer of resistant genes controls (Lapidot et al., 1997, pp. 1425-1428; from the hybrid lines to the backcross lines Lapidot, Weil, Cohen, Segev, & Gaba, 2007. was successful. pp. 143-148). In this study, the number of Plant height of the three F3 hybrid fruits per plant was relatively high in Roma lines was significantly higher than those x RW, Roma x Wild and Cherry red x Wild of the backcrossed lines. This indicated and total fruit yield (t/ha) was relatively the gene for tallness in the F3 hybrid lines high in Cherry red, Wosowoso and Roma x Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) 435 MM Segbefia, HM Amoatey, JK Ahiakpa, EK Quartey, AS Appiah, J Nunoo and R Kusi-Adjei Wild. These varieties/breeding lines would further improvement in fruit size (weight) however perform better in the rainy season towards high fruit yield and tolerance to as there is a higher incidence of the TYLCV TYLCVD. The obvious limitation of this disease in the dry season, which drastically study is that diagnosis based on symptom reduces total production with adverse expression alone may be inadequate since consequences for farmers (Robinson & other factors (mineral deficiencies) and Kolavalli, 2010, pp.17-19). Similarly, Osei attack by pests could play a major role in et al. (2010, pp. 315-323) reported that in the overall appearance of plants in the field. the rainy season, Ghana is able to produce It is however, relevant as a preliminary step to meet domestic tomato demand. In terms in screening the varieties/breeding lines in of weight of fruits, Wosowoso recorded the the breeding programme against TYLCVD. highest while Cherry red had the lowest In an earlier work (Segbefia et al., among the cultivated commercial varieties. 2015; pp. 17-24), TAS-ELISA detected Among the three F3 breeding lines, Cherry TYLCV in Wosowoso, Woso x Wild, red x Wild was the most prolific, producing Woso x WW, Roma and Roma x Rw under the highest number of fruits. Woso x Wild field conditions. The PCR confirmed the produced the highest total fruit yield among presence of TYLCV in all varieties/breeding the F3 breeding lines. lines except Roma x RW. Detection of The Wild tomato (S. pimpinellifolium TYLCV in the symptomless Wild Tomato L.) produced the highest number of fruits and the hybrids, Roma x Wild and Woso x in this study. However, due to smaller Wild and all backcrosses indicate they are fruit size, total fruit yield (t/ha) was low symptomless carriers of the virus. compared with the adapted varieties / breeding lines. In all cases, numbers of fruits CONCLUSION recorded by the breeding lines were lower Roma recorded the highest population than Wild tomato. However, the total fruit of whiteflies in the dry season and also yield (t/ha) of the breeding lines were higher exhibited the highest symptom severity in than that of Wild tomato. This indicates that all plants (ISSAP) and diseased plants (ISSDP) the backcrossing of the F3 breeding lines to during the study period. There was symptom the adapted varieties Cherry Red, Wosowoso reversal in Wild tomato and Woso x Wild at and Roma resulted in increased fruit size 6-8 WAT for both ISSAP and ISSDP indicating compared to Wild tomato. Therefore, with their potential source of resistance. Average the combination of desirable attributes such whitefly count showed very high positive as high level of resistance to TYLCV disease correlation (r = 0.93) with disease severity in the field, early maturity, semi-determinate (ISSAP); while average whitefly count, growth habit and large number of fruits, average percent disease incidence, ISSAP and breeders could select Roma x RW, Woso x ISSDP correlated inversely (r = -0.83) with WW Tomato and Cherry Red x CRW for yield (t/ha). Roma x Wild, Woso x Wild, 436 Pertanika J. Trop. Agric. Sci. 41 (1): 423 - 440 (2018) Field Evaluation of Tomato against TYLCV Disease Cherry Red x Wild, Roma x RW, Woso Czosnek, H., Kheyr-Pour, A., Gronenborn, B., x WW and Cherry Red x CRW could be Remetz, E., Zeidan, M., Altman, A., … & Zamir, selected for future breeding work based on D. (1993). 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