Centromeric banding pattern of mitotic chromosomes in Vigna vexillata (TVnu 73)

Vigna vexillata chromosome characterization was carried out using the Leishman C- banding technique. The results showed that the chromosomes mostly exhibited bands at both the centromeric and telomeric regions. These bands will serve, as a valuable marker for the identification of the chromosomes. Chromosomes 2 were the most variable and differed from the other chromosomes by the presence of satellite on the short arm. Diploid chromosome numbers of 22 consisting of 11 pairs of homologues were observed for V. vexillata. The homologues chromosomes were arranged in the descending order. The idiogram representing the chromosomes was also constructed.African Journal of Biotechnology Vol. 4 (5), pp. 400-402, 200

Segregation for seed weight, pod length and days to flowering following a cowpea cross

Field studies were conducted to evaluate the segregation of the F3 (early generation) and F6 (late generation) families for seed weight, pod length and days to flowering among cowpea inter-sub-specific crosses. A wide range of segregants were provided in this cross and families were highly significantly different in the three agronomic traits studied. The continuous distributions observed for these traits studied in both generations confirms the quantitative nature of inheritance for these traits. Broad sense heritability estimates ranged from 47.8 to 91.1%. Estimates of genetic advance ranged from high to low and were consistent in both generations for all the traits. The F3 and F6 generations were not significantly different in all the three agronomic traits. Intergeneration correlations ranging from 0.35 to 0.49 also revealed strong associations between traits measured in the two generations. A no significant drop was observed between F3 mean and the corresponding F6 mean. This suggests the existence of a good measure of additive and possibly of additive x additive components of variance (which alone are fixable through subsequent inbreeding) although some amount of dominance and duplicate epistasis (which are non-fixable) may also be operative. The results of this study indicate that selection in early generations for superior types is feasible.Des études en champs ont été conduites pour évaluer la ségrégation des familles en F3 (jeune génération) et F6 (génération avancée) quant au poids des graines, la longueur de la gousse et le nombre de jours à la floraison chez des sous-espèces de niébé croisées. Une large gamme de lignées ségrégantes était introduite dans ces croisements et les familles utilisées étaient sensiblement différentes pour les trois caractères agronomiques étudiés. Les distributions continues observées pour ces caractères étudiés au sein des deux générations confirment la nature quantitative du patrimoine héréditaire pour ces caractères. Les estimations générales d'héritabilité se rangeaient entre 47,8 et 91,1%. Les estimations de transferts génétiques allaient des plus basses aux plus élevées et elles étaient constantes au sein des deux générations pour tous les caractères étudiés. Les corrélations entre générations s'est rangées entre 0.35 et 0.49 et montrées aussi les fortes associations entre les caractères mesurés pour les deux générations. Un déclin non significatif était observé entre la moyenne de F3 et son correspondant de F6. Ceci suggère l'existence d'une bonne mesure additive et peut-être de l' additive x additive composante de la variance (fixable pendant le croisement ultérieur) même si certains traits de dominance et de double épistasies (non fixables) pourraient être opérationnels. Les résultats de cette étude montre qu'une sélection parmi les jeunes générations de races supérieures est faisable

SEGREGATION FOR SEED WEIGHT, POD LENGTH AND DAYS TO FLOWERING FOLLOWING A COWPEA CROSS

Field studies were conducted to evaluate the segregation of the F3 (early generation) and F6 (late generation) families for seed weight, pod length and days to flowering among cowpea inter-sub-specific crosses. A wide range of segregants were provided in this cross and families were highly significantly different in the three agronomic traits studied. The continuous distributions observed for these traits studied in both generations confirms the quantitative nature of inheritance for these traits. Broad sense heritability estimates ranged from 47.8 to 91.1%. Estimates of genetic advance ranged from high to low and were consistent in both generations for all the traits. The F3 and F6 generations were not significantly different in all the three agronomic traits. Intergeneration correlations ranging from 0.35 to 0.49 also revealed strong associations between traits measured in the two generations. A no significant drop was observed between F3 mean and the corresponding F6 mean. This suggests the existence of a good measure of additive and possibly of additive x additive components of variance (which alone are fixable through subsequent inbreeding) although some amount of dominance and duplicate epistasis (which are non-fixable) may also be operative. The results of this study indicate that selection in early generations for superior types is feasible

Response of cowpea varieties to phosphorus supply on an acidic Alumi-Haplic-Acrisol from Brazil

No Abstract. Nigerian Journal of Soil Science Vol. 16 (1) 2006: pp. 115-12