Genetic Diversity of Selected Upland Rice Genotypes (Oryza sativa L.) for Grain Yield and Related Traits

Seventy-seven upland rice genotypes including popular cultivars in Nigeria and introduced varieties selected from across rice-growing regions of the world were evaluated under optimal upland ecology. These genotypes were characterised for 10 traits and the quantitative data subjected to Pearson correlation matrix, Principal Component Analysis and cluster analysis to determine the level of diversity and degree of association existing between grain yield and its related component traits. Yield and most related component traits exhibited higher PCV compared to growth parameters. Yield had the highest PCV (41.72%) while all other parameters had low to moderate GCV. Genetic Advance (GA) ranged from 9.88% for plant height at maturity to 41.08% for yield. High heritability estimates were recorded for 1000 grain weight (88.71%), days to 50% flowering (86.67%) and days to 85% maturity (71.98%). Furthermore, grain yield showed significant positive correlation with days to 50% flowering and number of panicles m-2. Three cluster groups were obtained based on the UPGMA and the first three principal components explained about 64.55% of the total variation among the 10 characters. The PCA results suggests that characters such as grain yield, days to flowering, leaf area and plant height at maturity were the principal discriminatory traits for this rice germplasm indicating that selection in favour of these traits might be effective in this population and environment

Diversity analysis of sweet potato (Ipomoea batatas [L.] Lam) germplasm from Burkina Faso using morphological and simple sequence repeats markers

Collecting and characterizing plant material has been basic for crop  improvement, and diversity has long been seen as vital for rational management and use of crops. Thirty (30) morphological characters and thirty (30) simple sequence repeat (SSR) markers were used to assess the diversity among 112 sweet potato (Ipomoea batatas [L.] Lam) cultivars in Burkina Faso and to develop a core collection. Eight morphological  characters were able to differentiate the 112 accessions and to identify 11duplicates while 28 SSR markers were more informative in discriminating the accessions and to identify five duplicates. The diversity assessment using the two approaches revealed high diversity with a coefficient of 0.73 using the phenotypic data, while moderate diversity with a coefficient of 0.49 was obtained using the SSR markers. These results show no correlation between the two approaches (with dissimilarity index of 0.95). A core collection was constituted using the SSR based data while the eightdiscriminative phenotypic descriptors will be used in the identification of cultivars. Key words: Accessions, genetic diversity, germplasm, molecular markers, morphological characters, simple sequence repeat, sweet potato

Studies on estimation of heterosis for striga resistance in maize test crosses in Mali

Open Access ArticleHeterosis for yield, secondary traits and Striga resistance was estimated in maize test crosses generated from fifteen inbred lines and three testers using line by tester analysis. Hybrids, testcrosses and parents were evaluated for two years at Agricultural Research Institute, Sotuba and Sanankoroba, to identify combinations expressing high hybrid vigor in Mali under Striga- infested and Striga-free conditions. Under Striga-free condition TZISTR106/TZISTR1230, TZISTR106/TZISTR1223 and TZISTR1033/ TZISTR1223 appeared as the best hybrids combinations with respect to grain yield, while combinations TZISTR1207/TZISTR1226, TZISTR106 /TZISTR112,TZISTR106 / TZISTR113 and TZISTR106/ TZISTR1028 showed positive mid parent heterosis for grain yield and negative mid parent heterosis for Striga related traits under Striga infestation. These hybrids are worthy for further utilization

Combining ability for grain yield, agronomic traits and striga hermonthica resistance of yellow endosperm maize

Open Access Article; Published online: 17 Aug 2018Maize production is constrained by Striga hermonthica in Mali leading to high yield losses. Breeding resistant hybrid maize is a promising alternative for increasing farmers’ income. The objective of this study was to evaluate the response of test crosses to Striga hermonthica and identify high yielding and adopted hybrid. Forty-five F1 hybrids and three checks were evaluated under Striga-infested and Striga-free conditions in Sanankoroba and Sotuba rainy season. Data collection was carried on grain yield, anthesis silking interval, plant aspect, plant height, days to 50% tasselling and silking, Striga damage ratings and Striga count at 8 and 10 weeks after planting. General combining ability (GCA) of line and Specific combining ability (SCA) of hybrids effects were significant for most traits under both conditions. GCA effects had greater proportion of variance than SCA effects suggesting additive gene effects controlling the inheritance of yield and Striga resistance. Parental lines TZISTR112, TZISTR1214, TZISTR1222, TZISTR1223, tester TZISTR1207 and TZISTR106 were the best combiner for grain yield under both conditions and they could be used in hybrid development

Principal component analysis of early generation sorghum lines for yield-contributing traits and resistance to midge

Sorghum (Sorghum bicolor L. Moench) is a staple food crop in Niger. Its production is constrained by sorghum midge (Stenodiplosis sorghicola Coquillett 1898) and by the use of low-yielding, local sorghum varieties. To improve sorghum productivity, farmers need high-yielding and midge-resistant sorghum cultivars. The objective of this research is to evaluate genetic diversity among sorghum inbred lines for yield, yield-contributing traits, and resistance to midge. Two-hundred and eighty-two lines (280 recombinant inbred lines plus two checks) were evaluated at two experimental sites in Niger. An alpha (0.1) lattice design with two replications was used to conduct the trial. Principal component analysis was used to determine the relationship between grain yield and resistance to midge. The first three principal components (PC) accounted for 56.22% of the total genotypic variation. Based on the similarity of traits within and between members of clusters, genotypes were divided into 18 clusters. Genetic variability was present for the traits under study in the tested germplasm. Hybridization of midge-resistant genotypes from different clusters should be able to yield new genotypes combining high yield and other desirable yield-contributing traits

Identification of stable genotypes and genotype by environment interaction for grain yield in sorghum (Sorghum bicolor L. Moench)

Sorghum is a staple food crop in Niger and its production is constrained by sorghum midge and the use of low yielding, local sorghum varieties. To improve sorghum productivity, it is crucial to provide farmers with high yielding sorghum cultivars that are resistant to midge. We evaluated 282 genotypes in four environments of Niger Republic. Alpha (0.1) lattice with two replications was the experimental design. Genotype and genotype by environment (GGE) biplot analysis was used to study grain yield (GY) stability and G × E interactions. The results revealed that two distinct mega environments were present. Genotype L232 was the best genotype for GY in the first planting date at Konni and the first and second planting dates (PDs) at Maradi. Genotype L17 was the best for GY in the second PD at Konni. The second PD at Konni was the most discriminating environment while the first PD at Konni is suitable for selecting widely adapted genotypes for GY

EXPLOITATION OF GENETIC POTENTIAL OF SWEETPOTATO FOR END-USER TRAITS IMPROVEMENT

Sweetpotato ( Ipomoea batatas Lam) is a staple food globally, but it has remained underutilised resource in Ghana due to lack of consumer preferred cultivars. There is the need to develop staple-type sweetpotato cultivars which are preferred by consumers to increase sweetpotato use as a food security, health and industrial crop commodity in Ghana. This study was conducted to evaluate the breeding potential of sweetpotato germplasm for the development of farmer and consumer preferred varieties in Ghana. A total of 115 sweetpotato accessions were evaluated for genetic variability. Significant (P<0.01) differences were observed indicating genetic diversity. G x E was significant for all traits, except dry matter, sucrose, total sugar, and starch content. Phenotypic Coefficient of Variation (PCV) ranged from 4.78% for starch content to 63.40% for marketable root weight. Genotypic Coefficient of Variation (GCV) ranged from 4.07% for starch content to 55.35% for marketable root weight. Broad-sense heritability estimates varied from medium (0.61) to high (0.90) for all the traits, except for sucrose content. Predicted improvement over the means is 10 up to 105% for all traits, except starch (7.13%). This indicates sufficient useful genetic variation prospect which could be used to provide substantial improvement through selection of superior genotypes. The strong positive genetic association between dry matter and starch (r = 0.71), and strong negative relationship for sugar and dry matter (r = -0.77) and starch content (r = -0.99) indicates the possibility of developing non-sweet high dry matter sweetpotatoes, which are the preferred varieties in Ghana.La patate douce ( Ipomoea batatas Lam) est un aliment de base \ue0 l\u2019\ue9chelle mondiale, mais c\u2019est une ressource sousutilis\ue9e au Ghana en raison du manque de cultivars pr\ue9f\ue9r\ue9 par les consommateurs. Il est n\ue9cessaire de d\ue9velopper des cultivars de patate douce de type de base qui sont pr\ue9f\ue9r\ue9s par les consommateurs pour augmenter l\u2019utilisation de la patate douce comme la culture de la s\ue9curit\ue9 alimentaire, la culture de sant\ue9 et le produit industriel au Ghana. Cette \ue9tude a \ue9t\ue9 men\ue9e pour \ue9valuer le potentiel du mat\ue9riel g\ue9n\ue9tique du germeplasme de la patate douce pour le d\ue9veloppement des vari\ue9t\ue9s pr\ue9f\ue9r\ue9es par les agriculteurs et les consommateurs au Ghana. Un total de 115 germeplasmes de patate douce ont \ue9t\ue9 \ue9valu\ue9s pour la variabilit\ue9 g\ue9n\ue9tique. Des diff\ue9rences significatives de (P<0,01) ont \ue9t\ue9 observ\ue9es indiquant la diversit\ue9 g\ue9n\ue9tique. G x E \ue9tait important pour tous les traits, \ue0 l\u2019exception de mati\ue8re s\ue8che, le saccharose, le sucre total et la teneur en amidon. Coefficient Ph\ue9notypique de variation (CPV) variait de 4,78% pour la teneur en amidon \ue0 63,40% pour le poids de racine commercialisables. Coefficient g\ue9notypique de variation (CGV) variait de 4,07% pour la teneur en amidon \ue0 55,35% pour le poids de racine commercialisables. Coefficient g\ue9notypique de variation (CGV) variait de 7,60% pour la teneur en mati\ue8re s\ue8che \ue0 55,35% pour le poids de racine commercialisables. Estimations de l\u2019h\ue9ritabilit\ue9 au sens large variat de (0,61) moyen \ue0 (0,90) haut pour tous les traits, sauf pour la teneur en saccharose. L\u2019am\ue9lioration pr\ue9dite sur le moyen est de 10 \ue0 105% pour tous les traits, \ue0 l\u2019exception de l\u2019amidon (7,13%). Cela indique suffisamment la perspective de la variation g\ue9n\ue9tique utile qui pourrait \ueatre utilis\ue9 pour fournir une am\ue9lioration substantielle par la s\ue9lection de g\ue9notypes sup\ue9rieurs. Une forte relation g\ue9n\ue9tique positive entre la mati\ue8re s\ue8che et l\u2019amidon (r = 0,71), et une forte relation n\ue9gative pour le sucre et la mati\ue8re s\ue8che (r = -0,77) et la teneur en amidon (r = -0,99) indiquent la possibilit\ue9 de d\ue9velopper la patate douce qui est non sucr\ue9e, haute de mati\ue8re s\ue8che et qui sont les vari\ue9t\ue9s pr\ue9f\ue9r\ue9es au Ghana

Genetic Diversification and Selection Strategies for Improving Sorghum Grain Yield Under Phosphorous-Deficient Conditions in West Africa

Sorghum, a major crop for income generation and food security in West and Central Africa, is predominantly grown in low-input farming systems with serious soil phosphorus (P) deficiencies. This study (a) estimates genetic parameters needed to design selection protocols that optimize genetic gains for yield under low-phosphorus conditions and (b) examines the utility of introgressed backcross nested association mapping (BCNAM) populations for diversifying Malian breeding materials. A total of 1083 BC1F5 progenies derived from an elite hybrid restorer “Lata-3” and 13 diverse donor accessions were evaluated for yield and agronomic traits under contrasting soil P conditions in Mali in 2013. A subset of 298 progenies were further tested under low-P (LP) and high-P (HP) conditions in 2014 and 2015. Significant genetic variation for grain yield was observed under LP and HP conditions. Selection for grain yield under LP conditions was feasible and more efficient than the indirect selection under HP in all three years of testing. Several of the BCNAM populations exhibited yields under LP conditions that were superior to the elite restorer line used as a recurrent parent. The BCNAM approach appears promising for diversifying the male parent pool with introgression of diverse materials using both adapted Malian breed and unadapted landrace material from distant geographic origins as donors

Exploitation of Hybrid Vigor for Identification of Promising Sorghum F1 Hybrid for High Grain Yield and Resistance to Sorghum Midge

Sorghum is the second most grown cereal crop in Niger. However, sorghum production in the country is dominated by indigenous cultivars with low productivity. Productivity in grain sorghum has been achieved in developing countries around the world using hybrids. (is study was conducted to evaluate heterosis in F1 sorghum hybrids for grain yield and resistance to midge. Fifty F1 sorghum hybrids were evaluated for grain yield and resistance to midge. Variation for grain yield, midge resistance, and flowering time was observed. (e magnitude of better parent heterosis for grain yield and resistance to midge varied significantly among hybrids. Four hybrids combined high better parent heterosis for both grain yield and resistance to midge while eight hybrids were better than their better parent for resistance to midge. (ese hybrids performed well for grain yield and/or resistance to midge. (erefore, the parental lines involved in these hybrids can be advanced for commercial hybrids production or used in sorghum improvement programs

Genetic Variability and Its Implications on Early Generation Sorghum Lines Selection for Yield, Yield Contributing Traits, and Resistance to Sorghum Midge

Sorghum is the second most important cereal crop in Niger. The crop is grown in a wide range of ecological environments in the country. However, sorghum grain yield in Niger is limited by both abiotic and biotic constraints. Recombinant inbred lines derived from the cross of a local variety with a midge resistant variety and two local checks were evaluated during the 2015 rainy season across two planting dates in two environments in Niger. The objective was to investigate genetic variability for yield, yield related traits, and resistance to sorghum midge. High phenotypic coefficient of variation (PCV) versus genotypic coefficient of variation (GCV) was observed in both sites and planting dates. Across planting dates at both Konni and Maradi, grain yield, plant height, panicle weight, and midge damage had high heritability coupled with high estimates of genetic advance. At Konni, high genetic advance coupled with high heritability was detected for grain yield, plant height, panicle weight, and resistance to midge. There were similar results at Maradi for grain yield, plant height, and panicle weight. Therefore, selection might be successful for the above characters in their respective environments