Marker assisted development of wheat lines with enhanced nutritional quality
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Date
2018
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Punjab Agricultural University, Ludhiana
Abstract
The aim of present study was the genetic enhancement of grain micronutrient and yellow pigment content in high yielding wheat lines. The study was based on BC1F2 and BC2F2 introgression lines developed from crossing advanced backcross lines of T. durum with grain zinc QTL introgressed from T. monococcum and T. boeoticum, with high yielding varieties of North Western Plain Zone i.e. PBW621, HD2967 and WH1105 and two gene pyramided version of PBW343 (carrying rust resistance genes Yr10, Yr15, Lr24, and Lr28) as recurrent parent. A total of 210 BC1F3 and 210 BC2F3 progenies from different cross combinations were evaluated for grain zinc concentration, yellow pigment content and agronomic traits. Eighteen highly promising BC1F3 progenies (>80ppm zinc concentration) and 15 BC2F3 progenies (>75ppm zinc concentration) were identified and advanced at Keylong as ear to progeny rows. A total of 42 BC1F5 and 43 BC2F5 derivatives were evaluated in a square lattice design and analysis of variance revealed significant variation among the progenies for grain zinc, yellow pigment as well as agronomic and quality traits studied. The BC1F5 progenies from recipient parent WH1105 and tetraploid donor BF13 were recorded with highest grain zinc (64.1-67.9ppm) and iron concentration (29.8-36.0ppm). The highest grain yellow pigment content (5.35 ppm) was observed for the cross involving PBW703 as recipient and BF 21 as tetraploid donor parent. The markers for the previously mapped grain zinc QTL which was identified at diploid level in the donors, were found to be non polymorphic. Monitoring of backcross derivatives with the marker YP7A-2 linked to yellow pigment gene Psy-A1, revealed nine lines positive for high yellow pigment allele (Psy-A1c) indicating introgression from T. durum. To test the effect of environment on grain zinc concentration, eight high zinc BC1F5 lines and ten BC2F5 lines were evaluated in a randomized block design at two locations i.e. Ludhiana and Gurdaspur. The pooled analysis of variation revealed location effect to be significant for grain iron and zinc concentration. Furthermore, BF22/PBW698//PBW698 derivatives were crossed with BWL3560 (carrying Gpc-B1) with the aim of conglomerating enhanced protein content, zinc and yellow pigment content within the same wheat background. A total of 1068 F2 single plants were phenotypically analysed for grain iron and zinc concentration. High zinc lines were shortlisted and 192 F3 lines were sown in square lattice design. Molecular marker analysis of F3 progenies for Gpc-B1 gene (Xucw108) revealed 129 F3 lines to be homozygous positive. Correlation studies revealed that the improvement for four nutritional quality traits (grain protein, zinc, iron and yellow pigment content) was constrained and yield/yield components might have to be compromised.
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