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Abstract

Biofortification of maize is an inexpensive and locally adaptable method to alleviate Vitamin A deficiency which is one of the major health problems in the world. Maize displays considerable natural variation for carotenoid composition, including vitamin A precursors α-carotene, β-carotene, and β -cryptoxanthin. The gene encoding β--carotene hydroxylase 1 (crtRB1) underlies a principal quantitative trait locus associated with β--carotene concentration and conversion in maize kernels. 316 maize inbred lines that were obtained from CIMMYT (International Maize and Wheat Improvement Center), Mexico and Directorate of Maize Research, New Delhi were grown and evaluated for crtRB1 polymorphism using gene specific markers. In order to detect the crtRB1 polymorphism the primer HYDB 3?TE was used. The presence of 543 bp (Allele size 1) indicates high, 296+1221+1800 bp (Allele size 3) indicates medium and 296+875bp (Allele size 2) indicates lower level of β-Carotene in maize. DMR30 and DMR38 were recorded withallele size 1. Allele size 2 was recorded inDMR35, DMR16 andDMR254. Allele size 3 was recorded in DMR99, DMR102, DMR103, DMR112, DMR113, DMR104, DMR231, DMR26 and DMR19. The identified genotypes with favorable alleles for crtRBI polymorphism were evaluated for whole kernel carotenoids using spectrophotometer analysis and β-carotene content was evaluated using high performance liquid chromatography (HPLC). The total carotenoid content rages from10.17 μg/g to29.1 μg/g. The beta carotene content ranges from 0.33 μg/g to 9.27 μg/g. Medium level of β carotene was observed in DMR 26 (4.009362 μg/g), DMR 112 (2.009941 μg/g). Higher level was observed in DMR 104 (9.278696 μg/g) and DMR 38 (7.076111 μg/g). Lower level of beta carotene content was observed in DMR 35 (0.330467 μg/g), DMR 102 (0.277442 μg/g), DMR 103 (0.361596 μg/g), DMR 113 (0.810067 μg/g). In PCR assay the 543-bp allele of crtRB1 leading to higher β carotene concentrations, was detected only in lower frequency (1.03%). This study shows that the selection of maize inbreds with enhanced seed beta carotene content is possible by selecting for crtRB1 allele.

Biography

Dhyaneswaran Palanichamy is a master?s student in Biotechnology and Business Management at Tamil Nadu Agricultural University (TNAU), Coimbatore. He earned his bachelor?s degree in Biotechnology in TNAU and Masters of Professional Studies in Plant Breeding degree from Cornell University, NY, USA. He is about to pursue his PhD in Plant Breeding at Cornell University starting from fall, 2012.