Linkage of genes for anthocyanin and chlorophyll pigmentation in cowpea [Vigna unguiculata (L.) Walp.]

The inheritance of anthocyanin and chlorophyll pigmentation of various vegetative and pod characters were studied in cowpea [Vigna unguiculata (L.) Walp] cross P-737-2 x V-23. One to three pairs of genes were responsible for inheritance of these characters. Monogenic ratio of 3: 1 was observed for both pigmentation of pod tip and surface and pod streak. Duplicate ratio of 15: 1 and trigenic duplicate ratio of 63: 1 were obtained for pigmentation on peduncle tip and unripe pod colour respectively, while pigmentation on stipules and peduncle surface were controlled by any two of the three complementary genes and two threshold dominant genes giving F₂ ratios of 54: 10 and 11: 5 respectively. Pleiotropy and differential gene action were established among pigmentation on peduncle surface, stipules and unripe pod colour. Pigmentation on peduncle surface (Pgpls) was linked with peduncle tip (Pgpit), surface (Pgpits) and pod streak (Pst) with recombination value of 33.10, 43.71 and 38.41 per cent respectively. Pgplti was proved to be linked to four gene linkage group and Pgpit2 was linked to Gnp which belonged to separate two genes linkage group.