Gene action and heritability of yield components of dual-purpose sweetpotato clones

Abstract

In the past, extensive research has been conducted on breeding sweetpotato [Ipomoea batatas (L.) Lam] varieties with improved fresh root yields. However, little attention has been paid to breeding the crop for both improved storage root and vine yields for mixed crop-livestock farming systems. Consequently, the objective of this study was to determine gene action and heritability (H) of vine and root yield, and related yield components in sweetpotato. Eight parents selected for their contrasting attributes of root and vine production were hand-crossed in a half-diallel. Thirty-six generated families were evaluated at Rubona, Karama and Ngoma research stations of the Rwanda Agriculture Board. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for fresh root yield (FRY), root dry matter content (RDMC), dry root yield (DRY), root-to-vine ratio, harvest index (HI) and vine dry matter content. GCA/SCA ratios were much greater than 0.5 for all the root parameters DRY, RDMC and FRY, with 0.75, 0.81 and 0.88, respectively, suggesting that additive gene action was more important than non-additive gene action. H estimates were above 0.5 for all tested parameters, with FRY, HI and RDMC having high estimates of 0.80, 0.81 and 0.92, in that order. Promising families were K5132/61 × Wagabolige, 2005-179 × RW11-1860, 4-160 × 2005-179, K5132/61 × RW11-1860, RW11-2910 × 2005-179, Ukerewe × SPK004 and Ukerewe × 4-160. Progenies derived from the selected families are recommended for further field testing in advanced selection stages at multiple sites for future release.