Inheritance of Pod Length in Cowpea (Vigna unguiculata (L.) Walp.)

Abstract

Confirming the contestable genes that control a trait of interest is indispensable
for developing crop varieties. This underscores the importance of studying the
mode of inheritance of pod length in cowpea. The objectives of this study were to
estimate the gene numbers controlling pod length, its broad-sense heritability and
its nature of dominance in cowpea. Three cowpea lines (Ife Brown, TVNu699 and
TVu2723) were used to generate two crosses (Ife Brown x TVNu699 and
TVu2723 x TVNu699) in the screenhouse. Four generations (P1, P2, F1 and F2)
were evaluated in a randomized complete block design in 3, 3 and 4 replications
for parents (P1 and P2), F1 and F2 respectively. Data on pod length and seed weight
were subjected to statistical analyses. Additive variance (a) was higher than the
dominance variance (d) in both crosses. Crosses: Ife Brown x TVNu699 with a =
2.82 and d = 0.43 and TVu2723 x TVNu699 with a = 3.49 and d = 1.69. The
numbers of effective factors were estimated to be three and four in the two
crosses; while the degrees of dominance were 15.2% and 42.9%, respectively.
The broad-sense heritability estimates for pod length were 82.6% in the cross
TVu2723 x TVNu699 and 71.2% in the cross Ife Brown x TVNu699. It was
inferred that pod length in cowpea is controlled by multiple gene pairs, with
additive gene action playing a significant role over dominance, and high values
of the heritability estimates confirmed that the trait is transferable, indicating
strong potential for selection.