Genetic analysis of yield and flesh colour in sweetpotato
Pre-breeding information on the inheritance mechanism of important sweetpotato (Ipomoea batatas L.) agronomic traits is still limited. This study aimed at assessing the inheritance of five sweetpotato agronomic traits, viz. marketable fresh root yield (MFRY) and number (MNR), total fresh root yield (TFRY) and number (TNR) and root β-carotene content (RBCC). A 5 x 5 full diallel was performed and F1 progenies, evaluated in two environments alongside the parents. The data were subjected to ANOVA and DiallelSAS-05 Griffing’s method 1. Simple Sequence Repeat (SSR) based genetic distance and cluster analysis were performed on the parental lines using Jaccard’s coefficient and the unweighted pair group method with arithmetic averages (UPGMA). Significant differences (P<0.01) were detected among the genotypes for MFRY, MNR, TFRY, TNR and RBCC. Significant general and specific combining ability (P<0.01) effects were observed for all five traits. Additive gene action was predominantly involved in the inheritance of these traits. High broad sense heritability values were observed for the four yield parameters and for RBCC. The Jaccard’s similarity coefficient indicated moderate to low genetic similarity distances among the parents, implying high diversity. The knowledge on the inheritance and diversity of the parental genotypes enables more effective choice of parents in breeding improved varieties.
Keywords: β-carotene, combining ability, heritability, root yield, genetic diversity