Crossing potential in the production of persistent green seeds in Cowpea using gtand gc genes
Francisco Rodrigues Freire-Filho; Oyette L. Chambliss and Arthur Gene Hunter
Eight cowpea genotypes (Vigna unguiculata (L.) Walp.) combined in two sets of crosses were studied to evaluate parent’s potential and effects of genes for green testa (gt) and green cotyledon (gc) on days to first flowering (NDF), one hundred seed weight (SW) and dry seed yield per plant (SYP). Moreover, this study contributed to the identification of the best combinations of parents to form a population with wide genetic base for selecting lines having seeds with green color that persist to dryness. Two crosses segregating for both gt and gc genes were studied in Experiment 1, and a 3 x 5 partial diallel was studied in Experiment 2. In Experiment 1, the F2 generation of AU-GC-67 x Bettergreen had higher genetic variance than AU-78.1 x Bettergreen for the three traits. Results also showed that the genes gt and gc individually or in combination did not affect the characters studied. In Experiment 2, the effects of general combining ability (GCA) were higher than those of specific combining ability (SCA), indicating that the additive genetic effects were predominant in the expression of the three traits. Parents with the greatest GCA effects were: AR-92-537 and AU-GC-67 for earliness; AUKPH- 9/9-1 and Royal Blackeye for lateness; Colossus 80 for large seeds and AU-KPH-9/9-1, Colossus 80, Royal Blackeye and Bettergreen for seed yield per plant. According to the mean and the GCA of the parents and the mean and the genetic variance of the F2 generation, the crosses AU-GC-67 x AU-KPH-9/9-1, AU-78.1 x AU-KPH-9/9-1, AU-78.1 x Colossus 80, Bettergreen x AUBe, Bettergreen x Royal Blackeye and Bettergreen x Colossus 80 are the most promising/highly recommended to build a population with a wide genetic base for selection of high yielding lines with persistent green seeds.