Molecular marker analysis of F1 progenies and their parents for carotenoids inheritance in African cassava (<i>Manihot esculenta</i> Crantz)

Abstract

Cassava genotypes were assessed at genomic DNA level to estimate the genetic diversity within and between them using 36 simple sequence repeat markers (SSR). One hundred and forty-seven (147) F₁ progenies derived from crosses amongst the parental genotypes were used to determine the association between three SSR markers and beta-carotene content in cassava. For the diversity study, a total of 131 alleles with an average of 3.7 alleles per locus were found. One yellow fleshed root genotype clustered with a white fleshed root genotype indicating similarity in their genetic background. Three SSR markers were used to screen the parental genotypes and their 147 progenies for a beta-carotene gene. The yellow fleshed root parents and 141 of the F₁ progenies had SSR alleles associated with the presence of beta-carotene gene. The SSR markers identified for beta carotene at CIAT appeared linked to the trait as found in the parents, but evaluation in the progenies indicated that each marker did not account for high phenotypic variance individually. Marker NS 717 (allele 206) accounted for 20% beta carotene content and SSRY 301 (allele 331) accounted for 17%. There are minor QTLs that could probably be involved in beta carotene expression. The markers evaluated therefore do not sufficiently account for beta-carotene expression in the F₁ progenies.

Keywords: Cassava, simple sequence repeat (SSR), pro-vitamin A, diversity, validation. 

African Journal of Biotechnology, Vol 13(40) 3999-4007