Gene action and heterosis in F(1) clonal progenies of cassava for β-Carotene and farmers’ preferred traits

Gene action and heterosis provides information to assist breeder for selecting and generating improved plant recombinants. This study aimed at determining the gene action of selected cassava traits. The F(1) clones exhibited considerable phenotypic variability between families and offsprings. The best F(1) progenies had a higher amount of β-carotene (β-C) of 6.12 mg 100 g(−1) against 1.32 mg 100 g(−1) of the best parent. This superiority could be attributed to the over-dominance from the recombination of additive gene action and epistasis. The general combining ability (GCA) of parents and specific combining ability (SCA) of combinations were significant for different traits, and indicating the role of additive and non-additive gene action in controlling such traits. The significant GCA for β-C and postharvest physiological deterioration (PPD) indicates the role of additive gene action. The significant SCA for cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) showed a predominance of non-additive gene action. The F(1) progenies from the family Mavoka x Garukunsubire expressed the highest positive heterosis for CMD, dry matter and β-C. The high positive heterosis for β-C and DMC could be linked to transgressive segregation, because one of the parents was poor combiner.