03. QTL mapping for phsiological maturity in synthetic hexaploid wheat (Triticum aestivum L.) under drought stree
Abstract
Wheat is the main staple food and largest grain crop of Pakistan. An extended period of water deficits over months or years is the main cause of drought. Synthetic hexaploid wheat has drought tolerance characteristics and Opata is high yielding wheat cultivar. In order to investigate the genetic basis of the tolerance, a segregating mapping population (DR.MP. 5), composed of 84 double haploid lines derived from the cross Opata × SH349, was evaluated under field and drought stress conditions. The main objective was to identify early and late maturing wheat lines and to find out QTLs under drought stress. A field and tunnel experiment was performed for find out drought tolerant lines. Days to physiological maturity was selected as a crucial stage to find out best lines, as this stage is most vulnerable to drought stress. Ten early maturing lines were identified(84, 83, 7, 73, 43, 70, 22, 16, 6 and 15). Eight QTLs were identified during the present studies which were very important from practical point of view as these QTLs may be used in marker assisted selection (MAS) or gene cloning. Four QTLs were found under control and four under stress. These were all major QTLs. The source of tolerance in this germplasm is attributed to alleles on the A and B genomes of durum parents, or on the Aegilopstauschii’s D genome, or is a combination of genes that are pyramided as a result of A, B and D genome hybridizations.
Keywords: Drought stress, hexaploid wheat, Days to physiological maturity, QTL
