小麦赤霉病新抗源L693的抗性遗传机制及其抗性基因的分子标记定位

赤霉病抗源的匮乏是制约小麦抗赤霉病品种培育的瓶颈，发掘新的赤霉病抗性基因资源是有效防治该病害的根本途径。小麦赤霉病抗性新品系L693是从绵阳11和来源于中间偃麦草的小麦材料YU25杂交组合的一个F6:7家系中选育而成。连续5年的抗性鉴定表明，该品系对赤霉病的抗性稳定、年份间变异小等特点。根据F2代抗性分离的数据，初步推测该抗性受2对隐性基因控制。本项目以自育的抗赤霉病新品系L693为材料，旨在探明其抗性的来源与类型；揭示其控制抗性的基因性质及遗传规律。同时，利用分子标记对抗性基因进行染色体定位, 构建其连锁图谱；明确抗性基因的遗传位点，并筛选与其紧密连锁的分子标记。本研究将有助于发现小麦赤霉病抗源的新类型，并丰富其遗传基础；通过抗性基因的分子标记也有利于加快这一抗赤霉病新抗源在育种中的转移和利用。同时，对理解赤霉病抗性的分子机制及其抗小麦赤霉病新基因的发掘与利用亦有重要意义。

Fusarium head blight (FHB) is one of the most destructive wheat diseases worldwide, leading to yield reduction and poor grain quality. To develop and grow the disease-resistant varieties is the most economical, effective and environmentally friendly strategy to control the disease, while the shortage of resistant resource have severely impeded wheat resistance breeding to FHB. Therefore, to discover and identify new resistance resource to FHB is essential to control the disease..A new resistant wheat line named L693 was selected and identified from the F6:7 families of the cross MY11 and YU25, and YU25 was derived from the Thinopyrum intermedium by wide cross. The results of the resistance test executed in the past continual 5 years showed that the resistance of L693 to FHB is highly effective, phenotypic stable and little variation in various years, and this indicated that wheat line L693 is possible new resistance germplasm to FHB. The resistance test of both 390 and 557 F2 plants chosen from the crosses of L661/L693 and L693/L661 were conducted in the field with the method of single-floret inoculation, and the line L661 is very susceptible to FHB. The results of resistance test showed that the segregation of resistant phenotypes is accorded with an expected 7:9 resistant/susceptible in two F2 populations, which suggested that the resistance to FHB in wheat line L693 could be controlled by two pairs of recessive genes and this also further support that the resistance in L693 to FHB is different from the resistance previously reported and it is new germplasm..In the study, one of the purposes is to determine the origin with Thinopyrum intermedium and wheat specific DNA marker and the type of the resistance to FHB in wheat line L693 with the method of single-floret inoculation, the number of gene pair controlling the resistance, genetic basis and the segregation law of the resistance to FHB. The other purpose is to identify the chromosomal location of the resistance genes to FHB in wheat line L693 with F2:3 population and recombinant inbred line (RIL) population by molecular marker techniques, to construct the genetic map of the resistance genes and to screen some molecular markers closely linked with the resistance genes. .The project would play a key role in wheat resistance breeding to FHB as well as the basic research about the resistance to FHB. Firstly, it would afford some new resistance resource to wheat resistance breeding to FHB, and also broaden the genetic basis of FHB resistance. Secondly, it could screen and identify some molecular markers for wheat marker-assisted breeding to fast transfer and apply the resistance of L693 in wheat resistance breeding to FHB. Finally, it also could be very helpful to understand the resistance mechanism to wheat FHB and develop new wheat resistant varieties.