Genotypic variability and genetic parameters for root yield, dry matter and related traits of cassava in the Guinea Savannah ecological zone of Ghana

The aim of this study was to assess the agronomic performance and genetic parameters governing storage root yield and related traits in cassava genotypes in order to identify superior genotypes. The study involved 18 elite cassava genotypes which were arranged in a randomized complete block design with three replications and assessed for storage root yield and yield components (12 months after planting) in the Guinea savannah ecology of Ghana for three seasons. Analysis of variance indicated significant (p < 0.05) genotype and year main effects for fresh and dry root yields, dry matter content, starch yield and harvest index. Genotype × year effect was significant (p < 0.05) for fresh root yield, dry root yield and starch yield. Estimates of the variance components revealed greater genotypic influence for starch yield, fresh and dry root yields implying the potential for genetic gain with selection for these traits among the genotypes. Relatively high (69 %) broad sense heritability estimate was observed for dry storage root yield indicating the depth of genetic influence. Path coefficient analysis revealed a direct positive effect of dry matter content on dry storage root yield whilst dry storage root yield had direct positive effect on starch yield suggesting the possibility of indirect selection for starch yield through dry storage root yield. The study revealed ample genotypic variability among the cassava genotypes to warrant selection. Four genotypes, IBA 070134, IBA 419, IBA 950289 and IBA 980581 were identified for high and stable fresh and dry root yields for multilocational testing

Heritability and Associations among Grain Yield and Quality Traits in Quality Protein Maize (QPM) and Non-QPM Hybrids

Maize (Zea mays L.) is the main staple cereal food crop cultivated in southern Africa. Interactions between grain yield and biochemical traits can be useful to plant breeders in making informed decisions on the traits to be considered in breeding programs for high grain yield and enhanced quality. The objectives of this study were to estimate the heritability of grain yield and its related traits, as well as quality traits, and determine the association between quality protein maize (QPM) with non-QPM crosses. Grain yield, and agronomic and quality trait data were obtained from 13 field trials in two countries, for two consecutive seasons. Significant genotypic and phenotypic correlations were recorded for grain yield with protein content (rG = 0.38; rP = 0.25), and tryptophan with oil content (rG = 0.58; rP = 0.25), and negative rG and rP correlations were found for protein with tryptophan content and grain yield with tryptophan content. Path analysis identified ear aspect, ears per plant, and starch as the major traits contributing to grain yield. It is recommended that ear aspect should be considered a key secondary trait in breeding for QPM hybrids. The negative association between grain yield and tryptophan, and between protein and tryptophan, will make it difficult to develop hybrids with high grain yield and high tryptophan content. Hence, it is recommended that gene pyramiding should be considered for these traits

Gene action and combining ability studies for grain yield and its related traits in cowpea (Vigna unguiculata)

Identification of superior genotypes from variability generated via hybridization and understanding the nature of the gene action controlling grain yield and related traits are crucial for cowpea varietal improvement. A field experiment was conducted at the Savannah Agricultural Research Institute, Tamale-Ghana in the 2016 cropping season to examine the combining ability, genotypic and phenotypic correlations for grain yield and other agronomic characters in 25 cowpea genotypes (5 parents and 20 hybrids derived from a diallel cross of the parents). The result indicated that the general combining ability and specific combining ability varied for all characters measured signifying the prominence of both additive and non-additive genetic components in the present study. Non-additive gene action was important for grain yield, canopy width at maturity, plant height (PLHTF), number of seeds per pod, pod weight and days to 50% flowering (DFF). On the other hand, additive gene action was important for days to maturity (DM) and pod length. Parents PADI-TUYA and IT86D-610 were observed to be good general combiners for grain yield and other traits while IT86D-610 × PADI-TUYA, SONGOTRA × PADI-TUYA and IT86D-610 × SARC 57–2 were identified as promising specific combiners for grain yield and related traits. Selection criteria to improve the grain yield of cowpea should focus on plants with long peduncles, high canopy width and many pods per plant as these traits have high genetic correlation with grain yield

Heritability and Associations among Grain Yield and Quality Traits in Quality Protein Maize (QPM) and Non-QPM Hybrids

Maize (Zea mays L.) is the main staple cereal food crop cultivated in southern Africa. Interactions between grain yield and biochemical traits can be useful to plant breeders in making informed decisions on the traits to be considered in breeding programs for high grain yield and enhanced quality. The objectives of this study were to estimate the heritability of grain yield and its related traits, as well as quality traits, and determine the association between quality protein maize (QPM) with non-QPM crosses. Grain yield, and agronomic and quality trait data were obtained from 13 field trials in two countries, for two consecutive seasons. Significant genotypic and phenotypic correlations were recorded for grain yield with protein content (rG = 0.38; rP = 0.25), and tryptophan with oil content (rG = 0.58; rP = 0.25), and negative rG and rP correlations were found for protein with tryptophan content and grain yield with tryptophan content. Path analysis identified ear aspect, ears per plant, and starch as the major traits contributing to grain yield. It is recommended that ear aspect should be considered a key secondary trait in breeding for QPM hybrids. The negative association between grain yield and tryptophan, and between protein and tryptophan, will make it difficult to develop hybrids with high grain yield and high tryptophan content. Hence, it is recommended that gene pyramiding should be considered for these traits