Department of Botany
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Item Genotype by Environment Interaction Effect on Beta-Carotene and some Yield Components of Yellow Root Cassava (Manihot esculenta Crantz) Genotypes in Ghana(University of Ghana, 2008-06) Maroya, N.G.Item Ethnobotany, Bioactivity and Variation Studies of Traditional Ghanaian Anti-Malarial Plants(University of Ghana, 2000) Asase, A.An investigation on traditional plants used in the treatment of malaria in Ghana was conducted. The study involved a collection of information from an indigenous group of people living in the Wechiau Community Hippopotamus Sanctuary Ghana about their knowledge on plant species used for the treatment of malaria. It also involved a study of the bioactivity and variations within selected plant species in the sanctuary. The investigation on the indigenous uses involved ethnobotanical interviews and field studies. Forty-one species of plants in 19 families were mentioned as used for the treatment of malaria in the sanctuary. Eight of the species of plants. namely. Afrraegle paniculata, Haemastostaphis bateri, indigofera pulchra, monathotaxis sp., Ozoroa insignis. strychnos innocua,strychnos spmosa and Xeroderris stuhlmanuii have not been previously investigated for their anti·malarial uses. The efficacy of four anti-malarial species. namely, Cassia sieberiana, Haematostaphis barteri, Mitragyna mermis and Pseudocedrela kotschyiand was determined by testing their extracts against several organisms including Plasmodium,bacteria, fungi and an insect pest. The methods of the bioassays included mic:rodilution technique for in vitro antiplasmodial assay. TLC agar-overlay diffusion for microbial bioassay and a binary choice assay for insect anti-feedant testing. The extracts were moderately active against Plasmodium and varied in their activity against the test organisms. From the stem and root barks of Haematostaphis barteri three Stilbene compounds were isolated for the first time from a member of the family Anacardiaceae.The identification of stilbenes was made through the use of NMR and APCI-MS expenmeruation. Variation study using data from a range of characters including morpholgy, anatomy of barks, ecology. distribution, Comparative phytochemistry and molecular (AFPL markers) were conducted to understand infraspecific taxonomy of tbe four species of plants and for their conservation in the sanctuary. Data obtained from the morpnomemc measurements, maceration, field ecologica1 methods, specimen computerisation, phytochemical methods such as HPLC and LC-MS and AFLP methodologjes were used for the variations analysis. The variations in the selected species were largely due to morphological and chemical variability. The variations in the species of plants were found to be due to plasticity of environmental factors and that the taxonomies of the four species are stable in the sanctuaryItem Microflora of Some Ghanaian Herbal Teas: Their Control and Some Aspects of the Physiology of the Mycoflora(University of Ghana, 2001-10) Owusu, E.The micro flora of Ghanaian herbal tea comprising dried leaves of Cinnamon (Cinnamomum zeylanicum), Hibiscus (Hibiscus sabdariffa) and Lemon grass (Cymbopogon citratus) have been investigated under field and laboratory conditions. Hibiscus, Cinnamon and Lemon grass teas used for the experiments were supplied by Getrade Co. Ltd. Accra, already packaged for export shipment; packaged in thin (O.2mm) biodegradable polyethylene bags containing 40-60g of sample placed in earthenware clay pots (1.0cm high and IOcm wide) with a cover to fit. Fungal species isolated varied from one sample to another. Sixteen fungal species were isolated from Hibiscus, belonging to the genera Aspergillus, Cladosporium, Eurotium, Monoascus, Paecilomyces, Penicillium, Septodochium, Rhizopus and Syncephalastrum; thirteen fungal species belonging to the genera Aspergillus, Cladosporium, Emericella, Monoascus, Penicillium, Streptomyces and Rhizopus were resident in Cinnamon tea, while nine fungal species belonging to the genera Aspergillus, Cladosporium, Monoascus, Rhizopus and Syncephalastrum were enco~tered in Lemon grass tea. Aspergillus species (A. candidus, A. !umigatus, A. ochraceus, A. rubrum, A. terreus, A. wentii) predominated followed by Cladosporium (C herbarium, C cladosporioides, C macrocarpon). Some potential pathogenic bacteria, Flavobacterium meningosepticum, Pseudomonas cepacia, P. pseudomallei, Sphingomonas paucimobilis and Xanthomonas maltophilia were also encountered. Some of the aeromycoflora isolated from the farms from which the tea leaves were harvested (Aspergillus candidus, A. jimigatus, A. ochraceus, CladosporiumItem Genetic Improvement of Root Yield and Nutritional Quality of Cassava (Manihot Esculenta Crantz) In Sierra Leone(University of Ghana, 2017-12) Kamanda, I.Cassava storage root is a major staple. However, the tuber is poor in nutrients especially micronutrients. The study was conducted to improve the nutritional status of cassava with farmers’ preferred traits in Sierra Leone. The specific objectives were i) to assess adoption challenges, perception and preferences for provitamin A cassava among cassava value chain actors in Sierra Leone. ii) to estimate genetic diversity within provitamin A cassava germplasm using morphological, molecular tools and i-check device for establishing a collection in Sierra Leone. iii) to determine performance and stability of total carotene content and dry matter of selected provitamin A cassava accessions across environments.vi) to characterize F1 progenies for total carotenoid, iron and zinc and protein content using biochemical tool. v) to estimate the combining ability of 12 cassava parents and their F1 progenies for mealiness, dry matter, number of roots and fresh root yield. A participatory rural appraisal (PRA) was conducted in Bombali, Kailahun and Moyamba districts, to identify farmers’ and consumers’ adoption challenges, perceptions and preferences for provitamin. High production cost, low yield, scarcity of planting materials, high cost of fertilizers and agro-inputs, drudgery in peeling and processing and limited access to micro finance loan schemes, were identified as major challenges for provitamin A cassava adoption. The respondents show willingness to accept and adopt provitamin A cassava due to its perceived nutritional quality. A total of 188 cassava accessions cultivated in the southern part of Sierra Leone were assessed using molecular tools and the i-check device. The Cassava accessions were grouped into eight distinct clusters based on the morphological data while they grouped into nine distinct clusters based on the molecular analysis. A significant positive correlation was found between the morphological and molecular data sets (r = 0.104; p < 0.034) but the correlation was rather weak. Thirty provitamin A accessions with higher total iv carotenoid contents were selected to form a collection. The collection evaluated in 3 environments for the GGE biplot analyses for dry matter content (DMC) and total carotenoid content (TCC) showed significant variation among the Genotypes, Environments and their interaction. Genotypes TR-1182 and TR-1313 had the highest performance for DMC and TCC. Njala was identified as an ideal environment for selecting superior genotype for total carotenoid content and Pendembu as ideal for dry matter content. The performance of 868 F1 progenies (obtained from five crosses involving eight genetically diverse parents) was evaluated for selection of varieties with increased level of micro nutrients. F1 progeny 13 and 33 from cross IITA-TMS-IBA 120004 x IITA-TMS-IBA 120003 recorded the highest (28.0 μg-1) and lowest (6.0 μg -1) values for total carotenoid content with a grand genotypic mean of 14.7 μg -1. F1 progeny 41 and 12 from cross IITA-TMS-IBA 088693x IITA-TMS-IBA 088747 recorded the highest (8.1%) and lowest (4.2%) crude protein content with a grand percentage mean of 5.4%. F1 progeny from cross IITA-TMS-IBA 96/1165 x IITA –TMS-IBA 011368 recorded the iron content with a ranged 45.0 ppm to 59.2 ppm and harvested progeny with the grand mean 12.6 ppm. F1 progeny from cross MM96/81791 x IITA-TMS-IBA 088747 had the highest zinc concentration ranging from 4.5 ppm to 17.7 ppm with a grand mean 8.5 ppm. Micro nutrients analysis on F1 progenies revealed that there is variation for quality traits in cassava. In addition, a 12 x12 diallel study revealed highly significant differences for dry matter, number of roots and fresh root yield at P < 0.01, and 0.05 respectively. General combining ability (GCA) variance was significant for fresh root yield while estimates of specific combining ability (SCA) variance was highly significant for dry matter and number of storage roots. The significant difference observed for most of the traits for the parents and their F1 progeny revealed that genetic diversity exists among the germplasm and Progenies from crosses IBA120004 x IBA961165, IBA 961165 v x I088693 and IBA120004 x IBA961165 were the best combiners for number of storage roots, mealiness and fresh root yield.Item Genetic Variability for Drought Tolerance in Cowpea Recombinant Inbred Lines [Vigna Unguiculata (L.) Walp.] In Ghana(University Of Ghana, 2017-12) Mustapha , S.A.Drought is more prevalent in the semi-arid areas where cowpea has the greatest potential. It is unpredictable in occurrence so timing to avoid drought is not easy. Drought affects both vegetative and reproductive growth of cowpea resulting in significant yield losses. This study was therefore undertaken to: (1) assess farmers’ perceptions on the effects of drought on cowpea production in northern Ghana and identify farmer preferred traits in cowpea varieties, (2) identify drought tolerant cowpea recombinant inbred lines using wooden box screening technique, (3) determine grain yield and biomass loss of cowpea inbred lines under low soil moisture conditions, (4) assess genotype by environment interaction and stability of cowpea recombinant inbred lines in Guinea, Sudan and transition ecologies of Ghana, and (5) determine the effect of drought on cowpea inbred lines’ grain nutrient content, minerals and phytochemical variability among 22 inbred lines seed samples. Results from the Participatory rural appraisal (PRA) study indicated that, the farmers demonstrated a high understanding of climate variability. Insect pest infestation, drought, and low soil fertility were constraints faced by farmers in those production zones. Seventy percent of the farmers preferred varieties with large grain size, smooth or rough textured seeds with white coats depending on the location, and high expansion ratio. From the focus group discussions, 83.7% of farmers preferred varieties that were early and drought tolerant. Results obtained from Screen-house screening for seedling tolerance indicates that the chlorophyll content gradually decreased over the period of water stress. Chlorophyll contents taken at 7, 14, 21 and 28 days after water-stress application significantly varied among the inbred lines, but no significant differences were observed for the parental checks. Relative water content for the recombinant inbred lines during water-stress ranged between 20-70% for drought susceptible and drought tolerant inbred lines respectively across the population for screening. The parental lines used as checks both had relative water contents of 60% for the first screen-house experiment. Relative water content for the second experiment ranged between 22-74% for susceptible and tolerant recombinant inbred lines respectively. Leaf wilting after 7 days of water-stress correlated positively with chlorophyll content at 7, 14, 21 and 28 days of water stress, however, leaf wilting on 14, 21 and 28 days negatively correlated with chlorophyll content at 7, 14, 21 and 28 days of stress imposition. Relative water contents for 14 days of water stress correlated negatively with chlorophyll content at 7, and 14 days but correlated positively with chlorophyll content at 7, 14, 21 and 28 days of stress. Potential seedling tolerant inbred lines were 84, 406, 325, 223, 75, 186, 131, 20, 28, 230, 398 and 353. The genetic variability found for this morphological trait among these inbred lines in the screen-house study suggest the opportunity for selecting superior genotypes under water limited conditions in the field. The results obtained from the field drought study indicated that, water stress resulted in percentage yield reduction for most of the inbred lines and the parental checks. The highest percentage yield reduction was observed for inbred line 20 (57.83%). Inbred line 84 rather had yield increase under drought (-10.57) Inbred lines 255, 353, and 186, had mean grain yields of 1.83, 1.74, and 1.67 tonnes per hectare (t/ha). The lowest mean grain yields were obtained from inbred line 28 with grain yield of 0.89 t/ha. The parental checks IT93K-503-1 and 97K-279-3, had mean grain yields of 1.60 and 1.07 t/ha respectively. The highest mean grain yield under water stress conditions was obtained from inbred lines 186 and 255 with mean yields of 1.48t/ha whereas the lowest mean yield was obtained for inbred line 38 with grain yield of 0.68t/ha. Additive main effects and multiplicative interaction (AMMI) analysis indicate significant differences for all the traits across all the six environments. In this current study, the highest yielding inbred lines across all the six environments were 75, 186, 353, 57, 255 and 131. Under the three stress environments, inbred lines 131, 75, 353 and 255, were the best performing inbred lines. Inbred lines 396, 28, 189, 116, 38, 325, 131 and 84 performed well under well-watered conditions. The most stable inbred line across the six environments was 75, whereas the highest yielding inbred lines were 255 and 131. In general, the recombinant lines that proved to be drought tolerant both under screen-house and field experiments were 84, 186, 255, 131, 353 and 75. Biochemical analysis for seed related traits revealed that inbred lines responded differently to drought. Significant differences of water regimes on various phytochemical traits were only observed in phosphorus, lead, valine and dl-beta phenyl-alanin. Inbred line with family number 57 had the highest crude protein content of 46.90% under well-watered conditions. Inbred line 84 under water stress conditions had high levels of Mg and K. Inbred line 20 under well-watered conditions had the highest antioxidant content. For phenolic acid content, family 255 scored the highest. Quercetin and rutin were most abundant in inbred line 186 for both water-stress and well-watered conditions. Inbred lines with family numbers 84, 406 and 189 for water-stress treatment had highest amino acids such as glutamine, lysine and histidine. Farmer involvement in the development of new varieties should be encouraged to enable easy adoption of improved varieties for cultivation.Item Genetic Studies of Pearl Millet (Pennisetum Glaucum (L.) R. Brown) Downy Mildew Resistance in Senegal(University Of Ghana, 2017-12) Kanfany, G.Pearl millet is an important cereal crop for food security in Senegal. However, the production of this crop has stagnated due to several factors, among them, downy mildew. A participatory rural appraisal and a survey conducted in the groundnut basin of Senegal involving 150 farmers revealed the occurrence of the disease across the main pearl millet growing areas. Almost all the farmers interviewed (99%) were able to recognize the disease and 94% of them observed it in their fields during the just ended season of 2014. However, they neglected the damages caused by the disease and did not rank it as the main constraint to pearl millet production. They rather ranked Striga and low soil fertility as the main pearl millet production constraints. They unanimously considered grain yield as the most important trait to be incorporated in a new pearl millet variety. The spatiotemporal pathogenic variation of the downy mildew disease was also studied using pearl millet downy mildew resistance differential lines. Significant differences were observed among the genotypes, location, year and their interactions for downy mildew incidence providing evidence of spatio-temporal pathogenic variation. Except for ICMR356, the downy mildew resistant differential lines differed in their resistance to the pathogen from the four agro-ecological zones across the years. The highest average downy mildew incidence over the two years was recorded in Nioro (18.7%), Kolda (17.6%) and Bambey (12.1%) research stations while the mean downy mildew incidence was the lowest in Sinthiou (6.9%). Therefore, Kolda, Nioro and Bambey research stations should be used for screening pearl millet materials. Thus, a set of 99 inbred lines, derived from landraces collected in several West and Central African countries, were evaluated under field conditions in Bambey and Nioro research stations during the rainy season of 2016. A highly significant differences were observed among lines for the downy mildew disease parameters and other agronomic traits. The lines were classified into 3 clusters with disease parameters and plant height as the most discriminant factors. One of the groups contained 38 lines that were characterized as resistant, early flowering, and the tallest plants with longest panicles. Out of these 38 lines, 17 were crossed with SOSAT C88 and Souna3 following a line x tester mating design in order to study their combining ability. General combining ability (GCA) and specific combining ability (SCA) means squares were significant for most of the traits indicating that both additive and non-additive gene effects were involved in the control of the inheritance of these traits. However, the contribution of GCA to the total mean squares was higher than that of SCA for all the traits, meaning that additive gene action was more important in the inheritance of these traits. Lines IBL003-B-1, IBL091-1-1, IBL095-4-1, IBL110-B-1 and IBL206-1-1 had positive GCA effects for grain yield and negative GCA effects for downy mildew, flowering time and plant height. These lines can be used as parents to create synthetic varieties or F1 hybrids adapted to the groundnut basin agro-ecological zone. Positive mid-parent, best parent and standard heterosis were observed for hybrids IBL206-1-1 x Souna3; IBL091-1-1 x Sosat C88; IBL206-1-1 x Sosat C88; IBL001-4-1 x Souna3 and IBL003-B-1 x Sosat C88. An association analysis was conducted with 77 genotypes to identify single nucleotide polymorphisms (SNPs) markers associated with downy mildew resistance. Three sub-groups based on panicle length were identified and a rapid linkage disequilibrium decay was noted. Sixteen significant markers, located on four linkage groups (LG) were identified across locations. Among these SNPs, the ones located on LG6 explained 15 to 20% of the downy mildew phenotypic variation and were consistent across the two locations. These SNPs were located on the same LG that a Quantitative Trait Loci detected in a previous study against population of pathogens that originated from Senegal while the ones located on LG1, LG3 and LG4 were discovered for the first time under Senegalese environments and therefore could be considered as new markers. With the pearl millet genome sequenced, candidate genes surrounding these identified genomic regions can be identified and validated.Item Genetic Studies and Mapping of Beneficial Alleles from Wild Species to Improve Agronomic Traits in Cultivated Groundnut (Arachis Hypogaea L.)(University Of Ghana, 2017-12) Sambou, A.Groundnut (Arachis hypogaea L.) is a legume widely cultivated in tropical and sub-tropical regions. Although Senegal is among the largest African producers, yield has declined over the years. The narrow genetic diversity of the cultivated groundnut due to its monophyletic origin coupled with polyploidization has slowed down its genetic improvement using molecular tools. Wild species of groundnut are important sources of useful alleles that can be used to broaden the genetic base of the cultivated groundnut. However because of their inferior agronomic value, groundnut wild species have been little used to improve agronomic traits. Thus the present study was undertaken to enlarge the genetic diversity of cultivated groundnut and to estimate the relative contribution of the wild species to improve agronomic traits in cultivated groundnut. Specifically the objectives were to: i) identify the main constraints that farmers are facing in groundnut production and their varietal traits preferences; ii) identify promising breeding lines; iii) identify genomic regions that underlie the variation of the observed phenotypes and iv) evaluate the increase of the phenotypic value associated with the alleles of the wild species. A participatory rural appraisal (PRA) was conducted using focus group discussions (FGD) and questionnaires in three regions (Kaolack, Kaffrine and Tambacounda). Furthermore, an advanced backcross BC2F4:6 mapping population was developed at CERAAS (centre d’etudes regional pour l’amelioration de l’adaptation a la secheresse) from a cross between Fleur11 used as recurrent parent and a synthetic allotetraploid donor ISATGR52B (A. duranensis (AA) x A. valida (BB)) 4x. Two hundred BC2F4 families from this cross were genotyped with 128 microsatellite markers (SSRs) at the genotyping lab (CERAAS) and the BC2F4:6 progenies plus Fleur11 were evaluated in four different environments. The PRA study revealed that groundnut remained the main cash crop cultivated by farmers. Farmers were ready to adopt varieties that have high pod and haulm yield and large pod and seed size regardless of oil content. The main constraints highlighted by farmers were marketability and access to land. However drought was the constraint that farmers identified as the most important and that could be addressed by breeders. A large phenotypic variation was observed between the advanced backcross (AB) lines. The interaction between genotypes and environments was significant. The analysis performed in each site allowed selecting fifty lines based on the weight attributed to each target trait using the selection index. Among the fifty lines, eleven were constantly present across sites. The GGE biplot identified B7_32_8_1 and Fleur11 as the best performing lines in terms of pod yield. The genotyping analysis conducted on the BC1 progenies permitted the construction of a genetic linkage map which spanned a cumulative length of 1792 cM with an average marker density of 6.4 cM. Three hundred and thirty loci were mapped onto 20 linkage groups (LGs). The quantitative trait loci (QTL) analysis conducted with the genotyping and phenotyping data of the BC2F4:6 families revealed 38 QTL related to agronomical traits. Most of the identified QTL for seed related traits were located on LG B3. For 50% of the identified QTL, the wild alleles contributed positively to the variation of the trait. Five QTL (5) were newly mapped. For 4 out of the 5 QTL, increase of the phenotypic value was associated with the alleles of the wild parent. The QTL for undesirable traits from the wild species (deep pod constriction, pronounced pod beak and spread growth habit) were also mapped and markers linked to them identified. This study has demonstrated the potential of alleles from wild relatives to enrich the genetic base of cultivated groundnut and to improve agronomic traits.Item Genetic Analysis of Resistance of Cowpea [Vigna Unguiculata (L.) Walp.] To Alectra Vogelii Benth. In Burkina Faso(University Of Ghana, 2017-12) Zakaria, D.Alectra vogelii is a parasitic weed of the Schrophulariaceae family causing severe damage to cowpea in Southern, Eastern and Western Africa. Total yield losses occur in heavily infested fields. In Burkina Faso, A. vogelii has recently been observed to heavily infest fields causing damage. The objectives of the study were to: (i) identify farmers’ varietal preferences and assess their opinion on the parasitic weed A. vogelii; (ii) identify sources of resistance to A. vogelii in cowpea germplasm from Burkina Faso; (iii) determine gene action involved in cowpea resistance to A. vogelii and (iv) determine the genetic inheritance and the allelic relationship of the resistance genes. A participatory rural appraisal (PRA) was conducted in three districts to assess farmers’ awareness of the parasitic weed A. vogelii, and identify their preferred varietal traits. One hundred and twenty cowpea genotypes from INERA-Kamboinse germplasm were screened in a screen house for their response to three ecotypes of A. vogelii. Twenty five genotypes were selected from this list for field assessment. A gene action study was conducted with a 9x9 half diallel cross, the inheritance and the allelic relationship of the resistance genes were studied. The PRA revealed that farmers from western Burkina Faso knew A. vogelii as a parasitic weed better than those from eastern Burkina Faso. A. vogelii was ranked the third most important biotic constraint to cowpea production after Striga gesnerioides and insects. Farmers’ preferred traits were large sized grains with rough texture and white colour. Erect and prostrate short cycle cowpea varieties were also preferred varietal types. Varieties B301, Komcalle, IT98K-205-8, IT99K-573-2-1 and KVX414-22-2 showed resistance to all the three ecotypes of Alectra; these varieties except B301 also possess farmers’ preferred grain qualities. Djouroum local and Pouytenga-9 were the best landraces for Alectra-resistance. Significant genotype by environment interaction with differential reactions of cowpea genotypes to A. vogelii ecotypes were observed. The combining ability study showed significant effects of general combining ability (GCA) for days to flowering, days to Alectra shoot emergence, 100 seeds weight and severity of Alectra damage. Specific combining ability (SCA) was not significant for days to Alectra shoot emergence and 100 seeds weight. Additive gene effects were more important for all the traits except days to flowering suggesting that good selection progress can be achieved with proper choice of parents. Non additive gene effects were also involved in the expression of some parameters. The inheritance and allelic relationship study involved two Alectra resistante genotypes (B301 and KVx414-22-2). The segregation ratios showed that two dominant genes confer the resistance in B301. A single dominant gene is responsible for the resistance in KVx414-22-2. The three genes were all independent. The symbol Rav4 is proposed for the gene for resistance to Alectra vogelii in KVx414-22-2.Item Genetic Analysis Of Grain Yield And Related Traits In Sorghum (Sorghum Bicolor (L.) Moench) Under Phosphorus Deficient Field Conditions In Southern Mali(University Of Ghana, 2017-12) Chiaka, D.Sorghum (Sorghum bicolor (L) Moench), the fifth most important cereal in the world is a multipurpose crop that plays a crucial role in human diets. Sorghum grain yield is heavily constrained by low phosphorus levels that limit its availability for plant use. Genetic improvement approaches that combine high grain yields with tolerance to low phosphorus levels would greatly improve adoption of such sorghum varieties. High grain yield reduction as a results of low soil phosphorus levels have been reported in Mali and they form the primary focus of this study. Determination of farmer preferences for grain and panicle traits in sorghum was undertaken to understand farmer preferred traits in addition to high yield. Genomic segments responsible for grain quality, panicle traits and other yield related traits under high and low phosphorus levels were identified. Alternative selection strategies targeting grain yield improvement under both high and low phosphorus levels (P-deficient) field conditions were also explored. The influence of environment on sorghum 1083 BC1F5 BC-NAM progenies for grain yield were elucidated. Results from focus group discussions with farmers at Sibi and Dioila clearly indicated that in addition to high grain yield, there were high preferences for grain-hardened open panicles with good threshability. Early maturing sorghum varieties were also much preferred especially under semi-arid conditions. A high genetic correlation (rG = 0.81) for grain yield was detected under HP and LP condition. The direct selection for grain yield was predicted to be 13% more efficient than the indirect selection. Using a nested mapping approach, a total of 84 QTLs detected by both bi-parental and Association mapping approaches were found to define the genetic architecture of tolerance to low and high phosphorus levels in sorghum. Field evaluations of a set of 13 backcross nested association mapping (BC-NAM) populations was done under contrasting P levels. A multi-environment University of Ghana http://ugspace.ug.edu.gh iii evaluation of 298 sorghum lines for grain yield indicated that non-additive genetic variance was more important across years under contrasting phosphorus levels. The findings from this study will contribute to the improvement of knowledge about farmers’ sorghum preferred traits and genetic control of those traits LP field conditions culminating in genetic improvement of the crop and better adoption of new varieties by farmers.Item Genetic Analysis of Drought Tolerant Early Maturing White Maize (Zea Mays L.) Inbreds with Striga Resistance Genes from Zea Diploperennis(University Of Ghana, 2017-12) Chinyere, A.I.Recurrent drought and parasitism by Striga hermonthica Del. Benth constitute the two most important stresses limiting maize (Zea mays L.) production and productivity in sub-Saharan Africa (SSA). Yield losses can reach up to 85% when the two stresses occur simultaneously in the field. The use of resistant varieties is more sustainable, economical, and efficient for African farmers. Several early (90-95 days to maturity) Striga resistant maize hybrids have been commercialized in the sub-region. However, the levels of resistance are not as high as desired as they still support Striga emergence thus increasing the Striga seed bank in the soil each season. The International Institute of Tropical Agriculture (IITA) has developed new early maturing maize inbreds containing novel Striga resistance genes from Zea diploperennis. Knowledge and understanding of the mode of gene action conferring Striga resistance and drought tolerance in these new early maturing maize inbreds would be invaluable in developing hybrids adapted to both stresses in the sub-region. The objectives of this study were to: (i) determine the genetic diversity and reaction of these early maturing maize inbred lines under Striga infestation and drought environments, (ii) determine the mode of inheritance of Striga resistance in an early maturing inbred line containing resistance genes from Zea diploperennis, (iii) determine the combining abilities for grain yield and other agronomic traits and heterotic groups of 30 drought tolerant, early maturing inbreds with the Striga resistance genes, (iv) identify high yielding and stable hybrids under Striga-infested, drought and optimal growing conditions (v) examine the inter-trait relationship of early maturing maize hybrids under the Striga infestation and drought. Genetic diversity among 36 early maturing inbred lines was assessed using 8145 SNP markers. The cluster analysis and population structure analysis separated the inbred lines into four distinct groups based on their genetic distance indicating high level of genetic variability among the lines. Using the base indices for selection, 22% of the inbred lines combined resistance to Striga and tolerance to drought. Generation mean analysis was used to study the inheritance of resistance to Striga in the early maturing maize inbred line, TZdEI 352, containing genes from Zea diploperennis to facilitate its effective use in resistance breeding programmes in SSA. Only models that incorporated epistasis in addition to additive and dominance gene effects were adequate in explaining variation in the six generations studied. Epistasis played an important role in Striga resistance genes from Zea diploperennis in tropical maize. One hundred and fifty hybrids derived from crosses involving the 30 inbreds utilizing North Carolina Design II plus six hybrid checks were evaluated under artificial Striga infestation at Mokwa and Abuja, drought at Ikenne, Bagauda, Minjibir and optimal environments at Ikenne, Mokwa and Abuja, in 2013 and 2015. Significant GCA and SCA effects for grain yield and most measured traits were detected under the three research conditions. The higher values of GCA over SCA obtained for grain yield, flowering traits, plant and ear heights, husk cover, Striga damage and number of emerged Striga plants at 8 and 10 weeks after planting under Striga infested and optimal environments, indicated that they were controlled by additive gene action. The non-additive gene action was more important than the additive gene action for days to silking, anthesis-silking interval, ear height, stalk and root lodging, ears per plants, ear and plant aspects while additive gene action was more important for grain yield, plant height, husk cover, and stay green characteristics under drought environments. There were no maternal effects in the expression of the traits either under Striga infestation, drought or optimal growing environments. Inbreds TZdEI 268, TZdEI 352 and TZdEI 173 had superior positive GCA-male and GCA-female effects for grain yield and negative GCA-male and GCA-female effects for Striga damage and number of emerged Striga plants under Striga infestation indicating that they contributed to higher grain yield in their University of Ghana http://ugspace.ug.edu.gh iv hybrids and could be used to improve tropical germplasm for Striga resistance. The lines TZdEI 492 and TZdEI 378 with outstanding positive GCA effects for grain yield under drought environments could be used to improve tropical germplasm for drought tolerance. The inbred lines were classified into four heterotic groups across the research environments using GCA effects of multiple traits. The inbred lines classified into each heterotic group may be recombined to form populations that could be improved through recurrent selection. Grain yield ranged from 1134 kg ha-1 for TZEI 26 x TZEI 5 to 5362 kg ha-1 for TZdEI 173 x TZdEI 280 under Striga infestation, 579 kg ha-1 for TZdEI 314 x TZdEI 378 to 3601 kg ha-1 for TZdEI 479 x TZdEI 260 under drought and 2376 kg ha-1 for TZdEI 82 x TZdEI 71 to 7769 kg ha-1 for TZdEI 260 x TZdEI 396 under optimal conditions. The additive main effects and multiplicative interaction analysis identified TZdEI 173 x TZdEI 280, TZdEI 173 x TZdEI 492, TZdEI 441 x TZdEI 260, TZdEI 82 x TZdEI 260, TZdEI 71 x TZdEI 396, TZdEI 396 x TZdEI 131, TZdEI 396 x TZdEI 264, TZdEI 98 x TZdEI 352, TZdEI 157 x TZdEI 352, TZEI 18 x TZdEI 357, TZdEI 268 x TZdEI 378, TZdEI 157 x TZdEI 280, TZdEI 492 x TZdEI 441 and TZEI 60 x TZEI 5 as the highest yielding and stable hybrids with combined Striga resistance and drought tolerance genes. Also, they had reduced Striga emergence and host plant damage. These hybrids should be tested in multi-location and on-farm trials to confirm the consistency in performance and promoted for release and commercialization in the Striga endemic areas with short duration of rainfall in West and Central Africa to contribute to increased maize productivity, poverty alleviation and reduced Striga seed bank in the soil. Striga resistant and drought tolerant hybrids with outstanding performance across stress environments could be obtained through accumulation of favorable alleles for stress tolerance in parental lines. Ear aspect was identified as the most reliable secondary trait for indirect selection for grain yield under both Striga-infested and drought.