Genetic variability of kernel provitamin-A in sub-tropically adapted maize hybrids possessing rare allele of β-carotene hydroxylase

Vitamin-A deficiency is a major health concern. Traditional yellow maize possesses low provitamin-A (proA). Mutant crtRB1 gene significantly enhances proA. 24 experimental hybrids possessing crtRB1 allele were evaluated for β-carotene (BC), β-cryptoxanthin (BCX), lutein (LUT), zeaxanthin (ZEA), total carotenoids (TC) and grain yield at multi-locations. BC (0.64–17.24 µg/g), BCX (0.45–6.84 µg/g), proA (0.86–20.46 µg/g), LUT (9.60–31.03 µg/g), ZEA (1.24–12.73 µg/g) and TC (20.60–64.02 µg/g) showed wide variation. No significant genotype × location interaction was observed for carotenoids. The mean BC (8.61 µg/g), BCX (4.04 µg/g) and proA (10.63 µg/g) in crtRB1-based hybrids was significantly higher than normal hybrids lacking crtRB1-favourable allele (BC: 1.73 µg/g, BCX: 1.29 µg/g and proA: 2.37 µg/g). Selected crtRB1-based hybrids possessed 33% BC and 40% BCX compared to 6% BC and 5% BCX in normal hybrids. BC showed positive correlation with BCX (r = 0.90), proA (r = 0.99) and TC (r = 0.64) among crtRB1-based hybrids. Carotenoids didn't show association with grain yield. Average yield potential of proA rich hybrids (6794 kg/ha) was at par with normal hybrids (6961 kg/ha). PROAH-13, PROAH-21, PROAH-17, PROAH-11, PROAH-23, PROAH-24 and PROAH-3 were the most promising with >12 µg/g proA and >6000 kg/ha grain yield. The newly identified crtRB1-based hybrids assume significance in alleviating malnutrition