Conditional QTL Mapping Of Protein Component Contents In Wheat Seed With Respect To Starch Content

Wheat(Triticum asetivum L.)is one of the most important crops in the world, and so breeding new varieties with high yield and quality to achieve great economic benefits is the main goal of wheat production. According to solubility, protein is divided into four classes: albumin, globulin, gliadin and glutenin, and the change of protein component contents will has important effect on wheat quality. In this experiment, we used material of 168 doubled haploid(DH) lines derived from a cross between Huapei3×Yumai 57, and the starch content and protein component contents in mature period were evaluated in six environments in two continuous cropping seasons. A genetic linkage map comprised 357 markers were used for QTL. Conditional and unconditional QTL analysis using ICIMapping 3.3 and QGAStaation 2.0, and to evaluate possible genetic interrelationships between protein component contents and starch content. Identification of the QTLs that has positive effects on increasing protein component content without reducing starch content will prepare gene resources for molecular marker assisted selection and molecular polymerize breeding, and thus will provide a theoretical basis for breeding new wheat varieties with high yield and quality. The results were as follows:1. The relationship of every protenin component to starch were studied. Globulin, gliadin and glutenin content showed significant and negative correlation to starch content, and albumin and starch content were positively correlated at the same time.2. Unconditional additive QTLs controlling protenin component contents were mapped. A total of 17 unconditional additive QTLs(There were 4 QTLs of albumin, 3 QTLs of globulin, 6 QTLs of gliadin, 4 QTLs of glutenin) controlling protenin component contents were detected, among which 1 QTL(QAlu1B) was detected in each of three environments and 4 QTLs(QGlo1B、QGli7B、QGlu1D and QGlu3A) were found in each of two environments.Therefore, these QTL were expressed stably across environments. 7 main effect QTLs(contribution rates of more than 10%) were found(QAlu1B、QAlu1B-1、QAlu6A、QGlo1B、QGli1B、QGlu1B and QGlu1D).3. Conditional additive QTLs that controlling protenin component contents were mapped. 19 conditional QTLs(There were 5 QTLs of albumin, 3 QTLs of globulin, 5 QTLs of gliadin, 6 QTLs of glutenin) were detected in the DH population based on starh content. Of all these QTLs, QAlu1 B could increase albumin content and was irrelevant to starch content; QGlo6 A could increase globulin content and wound not reduce starch content, which overcoming the contradictions between globulin content and starch content; similarly; QGli1 B and QGli7 A could increase glutenin content and wound not reduce starch content, which overcoming the contradictions between gliadin content and starch content; QGlu1 B and QGlu1 D could increase gliadin content and wound not reduce starch content, which overcoming the contradictions between glutenin content and starch content.4. Conditional and unconditional epistatic QTLs that controlling protenin component contents were mapped. 2 pairs of unconditional epistatic and 2 pairs of conditional epistatic QTLs for protenin component contents traits were detected in this study. 1 additive QTL(QGli3A) participates in the formation of epistatic QTL.