小麦新抗源CH7103抗条锈基因的遗传及其与已知基因的关系

Inheritance of Stripe Rust Resistance Gene in Wheat Line CH7103 Introgressed from Thinopyrum ponticum and Its Allelism with Known Genes

为了更好地利用小麦条锈病新抗源,以衍生于八倍体小偃麦"小偃7430"的新抗源CH7103为材料,对其抗条锈性及抗病基因的来源、遗传模式和细胞学特征及其与已知抗病基因的关系进行了分析和鉴定。结果表明,CH7103苗期和成株期对条锈菌系条中31、32号生理小种表现免疫或近免疫,与其抗性供体小偃7430及其野生亲本的抗病侵染型相似,而其小麦亲本均感病,说明CH7103对条锈病的抗性来自彭提卡偃麦草。抗×感的F1代均表现免疫,侵染型为0～0;级,且F2、F2∶3、BC1代的抗、感分离比均符合显性单基因控制的分离模式。通过等位性检测,初步明确CH7103含有的抗条锈病基因与已有的抗CYR32小种的基因Yr5、Yr10、Yr15、Yr41不存在等位关系,可能属于新的抗小麦条锈病基因。细胞学研究表明,CH7103及其与小麦品种"中国春"等杂种F1的染色体数目均为2n=42,绝大多数花粉母细胞具有2n=21Ⅱ的配对构型,并能与小麦染色体完好配对。说明CH7103不含较大的外源染色体片段,是一个携带偃麦草抗条锈病基因的异源渐渗系。

CH7103 is a Thinopyrum ponticum-derived wheat breeding line,which was resistant to stripe rust and powdery mildew,and derived from cross between partial amphiploid Xiaoyan7430 and wheat susceptible cultivars.This study was made to determine the inheritance of resistance to stripe rust in CH7103,and to characterize the origin of the resistance gene and its allelism with known genes,The disease screening demonstrated that CH7103 and its donor Xiaoyan7430 as well as the wild parent were resistant at the seedling and adult stages to CYR31 and CYR32 of the prevalent and most widely virulent in China,whereas all the wheat parents involved were susceptible,indicating that the stripe rust resistance in CH7103 was possibly derived from Th.ponticum.Genetic analysis on the F1,F2,F2∶3 and BC1 populations from stripe rust resistant line CH7103 revealed that a single dominant gene was responsible for the adult resistance to CYR32.The allelism tests in the four F2 populations demonstrated that the stripe rust resistance gene in CH7103 was likely different from the known resistance gene Yr5,Yr10,Yr15 or Yr41.The cytological observation showed that the somatic chromosome number of CH7103 and its F1 hybrids involving T.aestivum cv.Chinese Spring and Taichang29 were 2n=42,and their most pollen mother cell had a regular pairing of 2n=21 II at meiosis,suggesting that this resistant line was cytologically a stable cryptic alien introgression with being largely identical to the chromosome constitution of bread wheat.