Abstract: Coleoptile length and Radicle length are the important indexes to evaluate resistance of wheat (Triticum aestivum L.) seedlings to stresses. For mapping quantitative trait loci (QTLs) for lengths of coleoptile and Radicle in wheat, a set of immortalized F₂ (IF₂) population (168 lines) from Huapei 3 ´ Yumai 57 double haploid (DH) lines was treated with distilled water (normal condition) and 10%, 20%, and 30% of polyethylene glycol (PEG-6000). The coleoptile length (CL) and radicle length (RL) of the parents and the 168 IF₂ lines were measured after 7 d of treatment. QTLs for CL and RL were detected using 323 SSR markers, which were distributed in the whole genome of wheat. Based on inclusive composite interval mapping (ICIM) method, we identified 11 additive QTLs for CL and 12 additive QTLs for RL under normal and the three stress conditions. Each locus explained 4.93%–35.37% of phenotypic variance. In the interval between Xcfd39.2and Xcfd22.2on chromosome 4B, QTL QCl4B had the phenotypic contribution of 35.37%. Another QTL QCl3D-a located between Xcfd223 and Xbarc323 on chromosome 3D was detected in both normal and 20% PEG-6000 treatments, and explained phenotypic variances of 7.83% and 11.74%, respectively. QTL QCl3D-b was located on the same chromosome and close to QCl3D-a. In the linkage groups 1A and 5A1, three and two QTLs associated with RL were detected respectively. On chromosome 6D, two QTLs for CL and RL were found in the interval between Xswes679.1 and Xcfa2129 and the interval between Xwmc412.1and Xcfd49, respectively. The major QTLs identified can be applicable in marker-assisted selection in wheat breeding for coleoptile and root.

Key words: Wheat, Immortalized F₂ population, Coleoptile length, Radicle length, Quantitative trait locus