Inheritance of phenolic contents and antioxidant capacity of dehulled seeds in cowpea (Vigna unguiculata L. Walp.)

Abstract The objective of the present research was to estimate the magnitude of genetic variability for total phenol content and antioxidant activity of cowpea seed and investigate the genetics of these traits using generation's means analysis. Seven pure lines, F1 and F2 generations as well as backcross populations (BC1) from three hybrid combinations, were grown in Randomized Complete Block Design (RCBD) in Ngaoundéré (Cameroon). For biochemical analysis, flour samples were produced from dehulled seeds. Analysis of variance indicated significant differences (p<0.01) among genotypes for phenolic contents and antioxidant capacity. No significant transgressive segregation was observed among generations. High values of heritability in broad-sense (0.81-0.93 for phenolics and 0.63-0.71 for antioxidants) were recorded indicating major role of genetic variance in the expression of these polygenic traits. In most of the crosses, genetic analysis showed significance (p<0.05) of the effects of additive, dominance, and epistatic genes for both traits. Approximately, at least 12 genes affected the phenolic contents while the antioxidant capacity was controlled by a minimum of nine factors. At 10% level of selection, an increase of 7.89 to 17.80% and 9.01 to 13.13% was predicted respectively for polyphenols content and antioxidant activity. Correlation between the phenolic contents and antioxidant activity was significantly positive (r = 0.74). These results suggested that breeding for increased antioxidant activity in decorticated cowpea seeds, to enhance the importance of this food stuff for the human diet, can be quite successful through recurrent selection in later generations.