Biofortification of sweet corn hybrids for provitamin-A, lysine and tryptophan using molecular breeding

• Published in: Journal of cereal science Vol. 96; p. 103093
• Main Authors: Mehta, Brijesh K., Muthusamy, Vignesh, Zunjare, Rajkumar U., Baveja, Aanchal, Chauhan, Hema S., Chhabra, Rashmi, Singh, Ashok K., Hossain, Firoz
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2020
• Subjects: MAS; QPM; Sweet corn; Vitamin-A; proA; BC; o2; Vitamin-A; SSRs; RPG; QPM; crtRB1; BCX; Sweet corn; MABB; VAD; sh2; MAS
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1016/j.jcs.2020.103093

Traditional sweet corn is poor in provitamin-A, lysine and tryptophan, deficiency of which causes serious health problems. Here, parental lines of two shrunken2 (sh2) -based sweet corn hybrids viz., ASKH-1 and ASKH-2 were targeted for introgression of crtRB1 and opaque2 (o2) genes through marker-assisted backcross breeding. Gene-based markers; umc1066 (SSR) and 3′TE-InDel were utilized for foreground selection of o2 and crtRB1, respectively in BC1F1, BC2F1 and BC2F2 generations. Background selection employing 102–113 polymorphic SSRs led to >90% recovery of recurrent parent genome. Reconstituted hybrids recorded high mean provitamin-A (18.98 μg/g) with a maximum of 7.7-fold increase over original hybrids (3.12 μg/g). High mean lysine (0.39%) and tryptophan (0.10%) with an average enhancement of 1.71- and 1.79-fold, respectively was recorded among reconstituted hybrids over original versions (lysine: 0.23%, tryptophan: 0.06%). Improved hybrids exhibited high phenotypic resemblance with their original hybrids. The average cob yield (11.82 t/ha) and brix (17.66%) of improved hybrids was at par with their original versions (cob yield: 11.27 t/ha, brix: 17.04%). These biofortified sweet corn hybrids rich in provitamin-A, lysine and tryptophan hold immense significance as multinutrient-rich balanced food. This is the first report to stack sh2, crtRB1 and o2 genes to improve nutritional quality in sweet corn.
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•Traditional sweet corn lacks adequate provitamin-A, lysine and tryptophan.•Two sweet corn hybrids were biofortified by introgression of o2 and crtRB1 genes.•Improved hybrids possessed significantly high provitamin-A, lysine and tryptophan.•Biofortified sweet corn hybrids would provide multinutrient-rich balanced food.•This is the first report of stacking o2 and crtRB1 genes in sweet corn.