Combining Ability of Sweet Potato [Ipomoea batatas (L.) Lam] Genotypes for Beta Carotene and Dry Matter Content in Southern Guinea Savanna, Nigeria
Roots of orange fleshed sweet potato varieties currently available in Nigeria contain high quantities of β-carotene or pro-vitamin A but have high moisture content. These varieties have been found to be a cheap and important remedy for vitamin A deficiency. The cream or white fleshed varieties on the other hand, have sweet taste with high dry matter content, giving a dry texture, a quality trait preferred in Nigeria. The objectives of this study were to examine the quantitative inheritance of important traits in sweet potato by means of a diallel analysis with a view to estimating the GCA and SCA components of genetic variance, and to determine the associated type of gene action controlling β-carotene content and root dry mass. A diallel crosses experiment using six parental sweet potato genotypes crossed in all possible combinations were carried out. Resultant thirty progenies were evaluated for beta carotene (β-carotene) and dry matter content in Landmark University, Omu Aran, Kwara State, Nigeria during the cropping season of 2012 and 2013. The 30 F1 progenies along with their parental lines were planted in the same field trial. The trial was laid out in 6 x 6 triple lattice in two replications. Highly significant (P≤ 0.01) differences were observed among the genotypes for all the tested traits. The average β-carotene content for the progenies was 2.86 (mg/100 g f.w.) while the dry matter content was 31.89%. The cross combination 199024.2 x Excel recorded the highest beta carotene (14.37 mg/100 g f.w) and dry matter content (40.10%), this candidate is therefore suggested for further evaluation.
Key words: Diallel analysis, Dry matter, Southern Guinea Savanna, Sweet potato, Vitamin A, β-carotene.