| Common wheat is one of the most important staple crops world-wide. The grain yield and other important agronomic traits and quality traits of wheat are generally controlled by multiple genes, and inherited as QTL. With the development of molecular genetics and genomics, location,seperation and expoiting QTL have become an important and essential component element in crop genetic improvement. The work will not only prepare gene resources for molecular marker assisted selection and molecular breeding by design, but also lay a foundation for fine mapping and clone some important genes. In the present study, we report a new genetic linkage map developed from an immortalized F2, which was generated from the cross between two elite Chinese common wheat varieties Huapei 3 and Yumai 57. QTL analyses were performed using the software of QTLNetwork 2.0 based on the mixed linear model approach. QTLs for plant height and tiller. The results were as the following1. A set of doubled haploid (DH) lines were used to construct an immortalized F2 (IF2) population comprising 168 different crosses. Based on the method of the IF2 population, the 168 RILs were first randomly divided into two groups, each group containing 84 RILs. The 84 RILs from one group were each paired with an RIL from the other group without replacement, producing 84 different crosses in one round of interbreeding. This procedure was repeated two times, producing a set of the IF2 populations containing 168 different crosses.2. Linkage map was constructed with 324 SSR markers covering the whole wheat genome, including 284 SSR, 37 ESTs loci, 1 ISSR loci and 2 HMW-GS loci, was constructed. This linkage map covered a total length of 2,485.7 cM with an average distance of 7.67 cM between adjacent markers. QTL analyses were performed using the software QTLNetwork version 2.0 based on the mixed linear model at P < 0.05 level. Four additive QTLs, 1 dominance QTL and pair of epistatic QTLs were detected, the total QTL effects detected for the plant height explained 20% of the phenotypic variation. One QTL qPh4D for plant height was identified on chromosome 4D, was identified on chromosome 2D, explaining 7.5% of the phenotypic variances. Dominance effect loci qPh2D was identified on chromosome 2D, explaining 1.6% of the phenotypic variances;Epistatic effects of loci was identified on chromosome 5B—6D,explaining 1.7% of the phenotypic variances . The results indicate additive effects, dominance effects and epistatic effects are important in genetics of wheat for plant height, which are also subjected to environmental modifications. These results further demonstrate that the use of " IF2" groups QTL positioning research methods contribute to the molecular marker-assisted breeding3. Linkage map was constructed with 324 SSR markers covering the whole wheat genome, including 284 SSR, 37 ESTs loci, 1 ISSR loci and 2 HMW-GS loci, was constructed. This linkage map covered a total length of 2,485.7 cM with an average distance of 7.67 cM between adjacent markers. QTL analyses were performed using the software QTLNetwork version 2.0 based on the mixed linear model at P < 0.05 level. Two additive QTLs, 1 dominance QTL were detected, the total QTL effects detected for the tiller explained 13.1% of the phenotypic variation. One QTL qTn5D for tiller was identified on chromosome5D, explaining 9.9% of the phenotypic variances. Dominance effect loci qTn5A was identified on chromosome 5A, explaining 2.88% of the phenotypic variances in Taian and explaining 2.68% of the phenotypic variances in liaocheng. The results indicate additive effects, dominance effects and epistatic effects are important in genetics of wheat for tiller, which are also subjected to environmental modifications. These results further demonstrate that the use of " IF2" groups QTL positioning research methods contribute to the molecular marker-assisted breeding...
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