Genetic enrichment of provitamin a through marker-assisted backcross breeding in heat and drought-resilient maize (Zea mays L.) inbreds

Abstract

Vitamin A deficiency is one of the most common problems that have been found to exist in human population. In order to address this problem, crop bio-fortification is considered to be a cost effective and sustainable approach. In this study we report the improvement of two heat resilient maize inbreds CAL1514 and CML451 having low Pro-vitamin A (β-carotene) concentration using high Pro-vitamin A (PVA) donor parent sourced from CIMMYT. The crtRB1 favorable allele associated with high PVA was used for foreground selection along with background selection of recurrent parent genome (RPG) during Marker Assisted Backcrossing (MABC). DArT-Tag SNP markers were used for screening of crtRB1 favorable alleles in BC2F1 generation. KASP and DArT-Tag SNP markers were used for background selection in BC1F1 and BC2F1 generations respectively. Background selection by 97 KASP SNP markers revealed the RPG varying from 60.11% to 75.71% in BC1F1 and selection by 3305 DArT-Tag SNP markers revealed the RPG varying from 84.56% to 89.63% in BC2F1 generations. We recorded high β- carotene content (KCAL-1-21-5 - 6.01 μg/g and KCML-1-9-1 - 5.62 μg/g) in the introgressed lines compared to their recurrent parents (CAL1514 - 0.19, and CML451- 0.13), while various agronomic traits was on par with their recurrent parents. The new improved β-carotene enriched inbreds hold immense potential as donors and parents in various biofortification programs.