Development Of Maize Hybrids With Enhanced Vitamin-E, Vitamin-A, Lysine, And Tryptophan Through Molecular Breeding

Malnutrition is a widespread problem that affects human health, society, and the economy. Traditional maize that serves as an important source of human nutrition is deficient in vitamin-E, vitamin-A, lysine, and tryptophan. Here, favorable alleles of vte4 (alpha-tocopherol methyl transferase), crtRB1 (beta-carotene hydroxylase), lcyE (lycopene epsilon-cyclase), and o2 (opaque2) genes were combined in parental lines of four popular hybrids using marker-assisted selection (MAS). BC1F1, BC2F1, and BC2F2 populations were genotyped using gene-based markers of vte4, crtRB1, lcyE, and o2. Background selection using 81-103 simple sequence repeats (SSRs) markers led to the recovery of recurrent parent genome (RPG) up to 95.45%. Alpha (alpha)-tocopherol was significantly enhanced among introgressed progenies (16.13 mu g/g) as compared to original inbreds (7.90 mu g/g). Provitamin-A (proA) (10.42 mu g/g), lysine (0.352%), and tryptophan (0.086%) were also high in the introgressed progenies. The reconstituted hybrids showed a 2-fold enhancement in alpha-tocopherol (16.83 mu g/g) over original hybrids (8.06 mu g/g). Improved hybrids also possessed high proA (11.48 mu g/g), lysine (0.367%), and tryptophan (0.084%) when compared with traditional hybrids. The reconstituted hybrids recorded the mean grain yield of 8,066 kg/ha, which was at par with original hybrids (mean: 7,846 kg/ha). The MAS-derived genotypes resembled their corresponding original hybrids for the majority of agronomic and yield-related traits, besides characteristics related to distinctness, uniformity, and stability (DUS). This is the first report for the development of maize with enhanced vitamin-E, vitamin-A, lysine, and tryptophan.