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Subject: Genetics and Plant Breeding × Author: Ashutosh Kumar × End date: 2016 × Start date: 2014 ×
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    ThesisItemOpen Access
    Introgression of Slow Rusting Genes lr34 and lr68 in BREAD WHEAT (Triticum aestivum L.) Through Marker Assisted Selection
    (University of Agricultural Science, Dharwad, 2016-06) Ashutosh Kumar; Desai, S.A.
    Present investigation was aimed to introgress slow leaf rust resistance genes, Lr34 and Lr68 into an elite, moderately susceptible bread wheat cultivar GW 322 through marker assisted selection and to identify superior segregants for yield and yield attributing traits as well as leaf rust resistance. The materials comprised of 180 lines of different segregating populations of the cross GW 322 X PARULA viz., BC1F2, BC1F3, F4, BC2F2, BC3F2, BC3F1 and BC4F1. High GCV and PCV values coupled with high heritability and high genetic advance over mean recorded for the traits such as productive tillers per plant and grain yield per plant. The highest per cent transgressive segregants were found in BC1F3 population for productive tiller per plant, thousand grain weight, grain yield per plant and Area Under Disease Progress Curve (AUDPC). Selection based on these traits in advanced generation will be effective. In BC2F4 population maximum number of plants were confirmed for presence of both Lr34 and Lr68 genes. The least AUDPC value was observed in plants having both Lr34 and Lr68 genes. 11 plants recorded D type leaf tip necrosis (LTN) associated with low AUDPC. Plants having Lr34 alone resulted in 14.98 per cent reduction in yield, while 16.36 per cent in presence of Lr68. On the contrary in presence of both Lr68 and Lr34 it was only 13.27 per cent, while highest reduction in yield was observed in the absence of both genes (32.25 %). The plants with both the genes in combination and superior in performance are the potential donar lines for further development of varieties for durable leaf rust. Marker assisted selection deduced that line no. 281-25 (F5) and 7-40-81 (BC2F4) were homozygous for both Lr34 and Lr68 genes. These homozygous lines will be evaluated further for durable resistance along with yield attributing traits under multilocation trials.