Studies On Resistance To Powdery Mildew And Stripe Rust In Wheat Germplasms

Powdery mildew and stripe rust are two of the major diseases in wheat. Resistant cultivars offer an effective ,economical ,and environmentally safe way to control them.Germplasms containing resistant genes are basis of wheat breeding for resistance to the diseases. wheat germplasms 91(260)3-3-8 and Zhoumai17 are resistant to powdery mildew and stripe rust respectively, while 92R137 03DP10 are resistant to both of them. Genetic analysis was carried out to understand the inheritance pattern of their resistance genes. Meanwhile the effectiveness of some known powdery mildew resistance genes in GuanZhong area was tested. Additionally, the advanced lines derived from 91(260)3-3-8×Changwu 134 was evaluated based on their response to powdery mildew and stripe rust pathogens and their agronomic performance. The results were as follows:1. 91(260)3-3-8 was further confirmed to be immune to powdery mildew. F1 s between 91(260)3-3-8 and susceptible wheat varieties Shaan225, Xiaoyan6, Han6172 and Yumai49 were found to be resistant to powdery mildew, and the ratio of resistant plants to susceptible plants was 3:1 in all four F2 populations. These results indicated that 91(260)3-3-8 carries one pair of dominant powdery mildew resistance genes .2. Zhoumai17 was near immune to CY32, a prevalent race of Puccnia stniformis in china . In order to understand the inheritance pattern of its resistance gene to CY32, the material was used to cross 02-1050-4,02-1094-3, susceptible material; their F1 plants were found to be resistant to CY32, and the ratio of resistant plants to susceptible plants was 3:1 in F2 generations of 02-1050-4×Zhoumai17 and 02-1094-3×Zhoumai17. The ratio of resistant plants to susceptible plants was 1:1 in BC1 generations of 02-1050-4×F1and 02-1049-3×F1.These indicated that Zhoumai17 carries one pair of dominant stripe rust resistance genes .3. Both 92R137 and 03DP10 carry two pairs of dominant genes that confer resistance to stripe rust and powdery mildew respectively, and they are inherited indepentantly.4. Genotypes carrying Pm16,Pm20,Pm21and the germplasm 91(260)3-3-8 were immune to powdery mildew in GuanZhong area of Shaanxi . Genotypes carrying Pm2+6,Pm2+Mld,Pm3a,Pm4a,Pm5,Pm17 were also risistant to powdery mildew, whereas ,those carrying Pm2+Ta,Pm3d,Pm3f,Pm4b,Pm8,Pm3e and Pm7 were susceptible to powdery mildew in GuanZhong area of Shaanxi.