Genetic variability for kernel B-carotene and utilization of crtRB1 3’TE gene for biofortification in maize (Zea mays L.)
M. Vignesh, Hossain Firoz, T. Nepolean, Saha Supradip, P.K. Agrawal, S.K. Guleria, B.M. Prasanna and H.S. Gupta
Carotenoids are the major sources of dietary precursor of vitamin A and act as potential antioxidant besides preventing diseases such as night blindness in humans. Vitamin A deficiency is a global problem, but is particularly prevalent in developing countries like India, where 31 percent of pre-school children are reportedly affected. Evaluation of genetic variability for kernel β-carotene in 105 maize inbreds of diverse pedigree from India- and CIMMYT-origin revealed significant variation ranging from 0.02 to 16.50 μg/g. One of the key reasons for wide variation of kernel β-carotene is due to the allelic variation at crtRB1 3’TE gene. Five among 95 inbreds possessed the favourable crtRB1 3’TE allele with a mean β-carotene concentration of 0.86 μg/g. In contrast, the same allele detected in 20 CIMMYT-Maize HarvestPlus genotypes contributed a mean kernel-carotene concentration of 11.29 μg/g. The contrast in β-carotene concentration in Indian and CIMMYT genotypes could be attributed to the presence of SNPs and InDels in crtRB1 3’TE locus, along with the presence/absence of favourable alleles of other important genes influencing the carotenoid biosynthetic pathway. Marker-assisted breeding has been initiated, to introgress the crtRB1 3’TE favourable allele using high carotene CIMMYT inbreds as donors, to develop provitamin A-rich maize cultivars suitable for maize growing regions in India.