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Sudan Journal of Agricultural Research

Quantitative trait loci analysis for drought tolerance in an advanced backcross population of spring wheat

Ibrahim, S.E., Schubert, A., Pillen, K., and Léon, J.

Abstract   

Advanced backcross Quantitative Trait Loci (AB-QTL) analysis was applied to identify favorable exotic alleles that improve drought tolerance in an advanced backcross population derived from a cross between the German spring wheat cultivar ‘Devon’ and the synthetic hexaploid wheat accession Syn084. The hexaploid wheat accession Syn084 was developed by the hybridizations of T. turgidum ssp. dicoccoides with T. tauschii. A hundred and seventy-seven BC2F4:6 lines were tested under well-watered and drought-stress treatments in the greenhouse. Eight traits were studied including grain yield, harvest index, number of spikes, 1000-grain weight, days to heading, days to maturity, carbon isotope discrimination, and dry weight of biomass. The advanced backcross lines were also genotyped with 117 Simple Sequence Repeat (SSR) markers. A total of 37 QTLs were identified for the eight traits. At 10 (27%) QTLs, the exotic alleles exhibited desirable effects improving traits performance under both treatments, ranging from 0.4% to 24.4% under well-watered and from 1.0% to 16.3% under drought-stress treatments, respectively. The exotic allele on chromosome 5D linked to the SSR marker Xgwm212 increased grain yield by 4% under drought-stress treatment. Five QTLs were detected for carbon isotope discrimination. Two of these QTLs overlapped with one or two of the QTLs affecting days to maturity, dry weight of biomass, and 1000-grain weight. These QTLs associated with carbon isotope discrimination might be used to identify important physiological traits that contribute to plant stomatal conductance and photosynthetic capacity relationships. The study also confirmed that the hexaploid synthetic wheat accession Syn084 harbors valuable alleles that can enrich the genetic backgrounds of cultivated spring wheat as well as they might improve drought tolerance traits.

Sudan Journal of Agricultural Research Vol. 15 (2010) PP. 1-18