Mapping Of A Major QTL For Pre-harvest Sprouting Tolerance Derived From Ae .tauschii And Application In Breeding

An artificial amphiploid RSP (2n=42, AABBDD) obtained by tetraploid landrace Ailanmai (Triticum turgidum L, 2n=28, AABB) and Aegilops tauschii (DD, 2n=14) expressed high tolerance to sprouting which derived from Aegilops tuuschii. Earlier study showed the tolerance was controlled by a major gene, located on chromosome 2D. In present study, we located the major gene using molecule marker for marker-assisted selection (MAS) in breeding.Segregation distortion of molecular markers analysis in the extremeness population, we detect a major QTL for pre-harvest sprouting tolerance on short arm of chromosome 2D in a synthetic hexaploid wheat (RSP)×common wheat (88-1643) cross. To identify QTLs for pre-harvest sprouting tolerance, we constructed two SSR-based genetic map of short arm of chromosome 2D in 2004 and 2005, respectively. One putative QTL associated with pre-harvest tolerance, designated Qphs. sau-2D.1, was identified within the marker intervals Xgwm261-Xgwm484 in 2004 and wmc112-Xgwm484 in 2005, respectively. The phenotypic variation explained by the QTL varied from 25.73% (2004 CIM) to 27.50% (2005 MCIM). Confidence intervals based on LOD-drop-off method ranged form 9 cM (2005 CIM) to 15.4 cM (2004 MCIM), which were almost completely within marker intervals Xgwm261-Xgwm484.Result of identifying the frequency distribution of genetype in 48 F₆ PHST plants of cross between the synthetic hexaploid wheat RSP and Chinese cv. MY11 showed the RSP allele of Qphs. sau-2D. 1 could improve the pre-harvest tolerance in different genetic background.HMW glutenin subunits from wheat were separated by SDS-PAGE. 8 plants has excellent HMW glutenin subunits (1Dx5+1Dy10) in 48 F₆ PHST plants, 4 of them has RSP allele of Qphs. sau-2D. 1. They are the precious genetic material for improving the quality of paste.