Studies on Genetics of Qtls for Yield, Yield Component and Fibre Quality Traits in Cotton
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Date
2016-08
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University of Agricultural Science, Dharwad
Abstract
To understand the types of gene action controlling sixteen yield, yield component and fibre quality traits in cotton, QTL mapping was performed to dissect the main-effect QTLs (M-QTLs) responsible for the trait performance in 150 recombinant inbred lines (RILs) of interspecific hybrid DCH-32 and two testcross (TC) F1 populations derived from these RILs. Totally, 450 genotypes along with six checks were evaluated at two locations (Dharwad and Devihosur) during kharif 2015 in augmented design.
The analyses of variance and the PCV and GCV indicated the presence of wide genotypic and phenotypic variation for all the traits studied. Correlation between seed cotton yield and fibre length and strength were negative. The TC hybrids viz., DRBH-83 x Sahana (3,490 kg/ha) followed by DRBH-56 x Sahana (3,318 kg/ha) and DRBH-32 x Sahana (3,317 kg/ha) recorded significantly higher seed cotton yield compared to check, DHH-11 (2,407 kg/ha). DRBH-63 x Surabhi, recorded significantly higher seed cotton yield (3198 kg/ha) with significantly higher fibre length (29 mm) and strength (27.20 g/tex).
The genetic linkage map constructed in RIL populations using Cotton SNP 63K array Bead Chip was utilized for QTL analysis in RILs and TC hybrids. Totally, 95 M-QTLs were identified and classified into two predominant groups, additive QTLs (74) detected primarily in RILs and dominant QTLs [21; 5 (23.80%) from TCF1s of Sahana and 16 (76.19%) from TCF1s of Surabhi] identified exclusively in TC populations. Over-dominant QTL (qSCY-22-1) flanked by i57905Gb and i01031Gh markers (11.96 and 13.33% phenotypic variation) were found common between TCF1 of Surabhi and Surabhi Hmp. In between i38941Gh and i11395Gh markers, three traits viz., lint index (qLI-25-1), ginning outturn (qGOT-25-1) and seed cotton yield (qSCY-25-1) were co-localized on chromosome 25. Genetic effects of these identified QTLs with linked markers have significant implications in genetic improvement of cotton through marker assisted selection.