Studies on the inheritance pattern of joints, pod and flower pigmentation in cowpea [Vigna unguiculata (L) walp.]

Abstract

Genetic studies were carried out to elucidate the inheritance pattern of plant, flower and pod-tip pigmentation in cowpea. The parental varieties were selected based on their contrasting plant and flower pigmentation. These varieties were grown in the screen house between May, 2002 and October, 2003, and sufficient number of parental F1, F2, backcross and F3 seeds were obtained. The F1, F2, and backcross along with parent seed were planted in the field during the cropping season covering July-
October, 2003. Observations were taken on joint pigmentation, flower colour and pod traits on individual plant basis in each population. The results were analyzed for genetic segregation, to determine the number of genes controlling these traits and interactions between them. The joint pigmentation was controlled by one dominant gene. The coloured margins on the standard and wings of flower were controlled by one dominant gene; the purple standard and wings was also controlled by
a single dominant gene and it was allelic to the gene controlling the coloured margins. The purple wing with white standard was controlled by another dominant gene which was  different from the ones controlling pigments on the standard petal. The pigmented (purple) calyx was controlled by two genes and it was pleiotropic (tightly linked) to pod-tip as well as purple backline on standard petal. Of the two genes controlling the calyx colour, one controls joint pigmentation such that in the absence of joint pigmentation is prerequisite for calyx, pod-tip and backline pigmentation.