Yield stability analysis of pearl millet hybrids in Nigeria

Genotype x environment interaction in pearl millet [Pennisetum glaucum (L.) R.Br.] was studied for grain yield by growing 90 genotypes consisting of 81 hybrids and 9 inbred parents at 5 locations for 2 years. Genotype x environment interaction was observed, a large component of which was accounted for by non-linear regression on the environment means. Although the linear portion was significant, its magnitude was smaller than that of the non-linear component indicating the significance of environmental effects on the genotypes. Six hybrids were found to be stable across the environments. They yielded above the average mean yield of all the genotypes under test, with a slope of unity and the mean square due to deviation from regression equal to zero.Keywords: Genotype x environment interaction, yield, stability, pearl mille

Generation mean analysis of dual purpose traits in cowpea (Vigna unguiculata [L.] walp)

Dual-purpose, the relative ratio of grain to fodder productivity of cowpea (Vigna unguiculata) is one of the major factors affecting the adoption of new varieties in sub-Saharan Africa. Efforts have been made to improve either the fodder or the grain productivity separately. However, there is the need to develop a variety with both good grain and fodder productivity. Gene effects for dual-purpose traits were estimated from the combined analysis of the parental, F1, F2 and backcross populations involving one fodder cowpea and two grain type cowpeas with the aim of understanding the genetic basis of these characteristics. The fodder parent had significantly better performance compared to the grain types for all dual-purpose traits. Transgressive segregates for high and low fodder yield were observed, suggesting that the fodder yielding genes were dispersed among the parents. Frequency analysis showed that all the F2 populations for fodder yield exhibited a continuous distribution, suggesting that inheritance of fodder yield is quantitative in nature and may involve more than two genes. Epistatic effects were found to be important for all dual-purpose traits (days to first flower, plant height, pod weight, leaf weight, branch weight, seed weight, biomass and fodder yield). Fodder yield per plant appeared to be influenced by both additive and non-additive gene effects, whereas grain yield was influenced by complementary gene action. Duplicate gene interaction was predominantly involved in the inheritance of most of the structural traits (plant height, leaf weight and branch weight). For genetic improvement of fodder and grain yield, utilizing non-additive components, intermating among selected segregates in early generation or reciprocal recurrent selection should be effective approaches.Keywords: Gene effects, fodder, Vigna unguiculata, generation mean analysi

Correlations and Correlated Responses in Upland Cotton (Gossypium hirsutum L.)

Plant breeders must be concerned with the total array of economic characters in their efforts to develop a crop variety acceptable to farmers. Their selection endeavours must therefore take into consideration how changes in one trait affect, simultaneously changes in other economic attributes. The importance of correlations and correlated responses is therefore self evident in plant breeding endeavours. In this study F3 progenies from a cross between two cotton lines SAMCOT-9 x Y422 were evaluated for two years and performance data were used to obtain correlations between nine agronomic and fibre quality traits in upland cotton. The results indicated that plant helght was significantly and positively correlated with seed cotton yield, number of sympodial and monopodial branches, seed index, fibre length and micronaire index. Positive and significant correlations were also obtained between : seed cotton yield, tint percent and fibre strength and fibre length. Significant negative correlations were obtained between : plant height and lint percent ; number of monopodial branches, sympodial branches and lint percent ; fibre length, fibre strength and micronaire index. The correlated responses in the other eight traits when selection was practiced for seed cotton yield in the present study shows that it might be more profitable to practice direct selection for seed cotton yield compared to selecting for seed cotton yield through any of the other traits

Genetic, phenotypic and environmental variances and character associations in Kenaf

Kenaf (Hibiscus cannabinus L.) is an important food and livestock feed in Nigeria, which has hitherto been ignored in genetic improvement. Data obtained from evaluating fifty-seven diverse genotypes of Kenaf for two years in Samaru in the Nigerian Guinea Savanna ecological zone were used to study genetic variability and interrelationships between seed yield and its components. The results indicate a preponderance of genetic components of variance for seed yield, plant height, number of seeds per pod and 1000 seed weight indicating that selection for these traits should result in heritable improvements. Seed yield was found to be positively and significantly correlated with plant height, number of seeds per pod and 1000 seed weight. Significant and positive correlations were also obtained between plant height and number of capsules per plant and between 1000 seed weight and number of seeds per pod. The path-coefficient analysis indicates that number of seeds per pod and 1000 seed weight had the highest direct effects on seed yield. It is suggested that for a meaningful seed yield improvement programme, efforts should be directed towards the best balance between number of seeds per pod and 1000 seed weight. Key words: Hibiscus cannabinus, Nigeria, path-coefficient analysis RÉSUMÉ Kenaf (Hibicus cannabinus L.) est une importante nourriture et un aliment pour les animaux au Nigeria, qui a été littéralement ignoré dans l'amélioration génétique. Les données récoltées durant l'évaluation de cinquante sept diverses gênes de Kenaf pour deux ans en Samaru dans la zone écologique de la savane guinéenne du Nigeria étaient utilises pour étudier la variation génétique et l'interrelation entre le rendement en graines et ses composantes. Les résultats indiquent une prépondérance des composantes génétiques dans la variance du rendement en graines, la taille de la plante, nombre de graines par gousse et le poids de 1000 graines indiquant une sélection pour ces races conduirait à une amélioration de l'héritage. Le rendement en grains était positivement et significativement corrélé avec la taille de la plante et le nombre des capsules par plante et le poids de 1000 graines, et nombre de graines par gousse. L'analyse des coefficients des corrélations indique que le nombre de graines par gousse et le poids de 1000 graines avaient l'effet direct le plus élevé sur le rendement en graines. Il est recommandé que des efforts soient orientés vers l'équilibre entre le nombre des graines par gousse et le poids de 1000 graines, pour que l'impact du programme d'amélioration de rendement soit significatif. Mots clés: Hibicus cannabinus, Nigeria, analyse des coefficients de correlations African Crop Science Journal Vol.12(4) 2004: 321-32