Selection And Identification Of Wheat-Thinopyrum Intermedium Substitution Line And Addition Line With Resistance To Wheat Stripe Rust

Wheat stripe rust (yellow rust), caused by Puccinia striiformis Westend. F. sp.trutuci, is the primary world-wide low-temperature disease and one key factor limiting the yield of wheat. China is the largest occurrence land of wheat stripe rust in the world, particularly in Huang-Huai and Yangtzi river valley, stripe rust has been the main wheat disease. Because of the rapid variation of the stripe rust races , some resistant genes in wheat have lost their resistance. So there is a great need to find and introduce new resistant genes to wheat varieties and enhance their disease resistance. It is known that the relative species of common wheat are the good resource of resistance genes. Thinopyrum intermedium is one wild relative of common wheat with many excellent properties, such as more flowers, more seeds, increased protein content, resistance to many diseases and so on. Due to easily cross with common wheat, Thinopyrum intermedium is widely used in wheat breeding. Zhong 4 is a partial amphiploid sythesized by wheat and Thinopyrum intermedium, which contains novel resistance genes to wheat stripe rust. Therefore it would be a great significance to introduce the novel resistant genes from Zhong 4 into common wheat and create new wheat germplasm.By using resistance test in seedling stage, we screened 19 lines that show high resistance to CY31 from 90 lines of F5 or F6 generation materials after the cross and backcross of Chinese Spring Phlb mutant and Zhong 4. The 19 lines showed the same resistance level to that observed in the year 2003 and 2004. So we proposed that the resistance gene has been successfully introduced from Zhong 4 into the common wheat. The resistance was effective and stable.The mitosis metaphases of the root cells of 19 resistance lines were observed. It was showed that the chromosome number in all samples is even, giving 2n=42, 44, 46, 48 and 52 respectively. One line was obtained in the screening that had 42...