Anaylysis Of Resistance Genes To Stripe Rust In Current Winter Wheat Cultivaries In China

In China, wheat is grown on approximately 24 million hectares with an annual yield of 100 million tones and is the second important corp. Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a destructive disease in all winter wheat growing regions and is considered the most important disease of wheat in China. Resistant cultivars have been considered the most effective, low-cost, and environmentally safe approach to control the disease. However, the rapid development of new Pst races often circumvents the resistance in cultivars within 3-5 years. Seven nationwide cultivar replacements have taken place in China since the 1950s due to repeated appearances of new virulent races. the fact that lacking of effective resistance source and irrational using of resistance genes, make the most basic measure through the resistant cultivar control stripe rust cannot play its proper role. In recent years, major yield losses were prevented by widespread and timely applications of fungicides based on accurate monitoring and prediction of disease epidemics. In the long run, searching and discovering new genes, reasonable using and layouting current stripe rust resistance of genes, is still important work of wheat resistant rust breeding。In order to realize the resistant level of the current varieties to stripe rust, 494 wheat cultivars and lines were collected from the Northwest-Central North-The Middle and Lower Reaches of Changjiang River epidemic region and evaluated by stripe rust during seeding and adult stage. Then identification the distribution of stripe rust genes Yr5, Yr10, Yr15, Yr24/Yr26, Yr9, Yr17 and Yr18 among these materials. Finaly evaluating the differential host and known gene cultivars to stripe rust during seeding and adult stage both in Yangling and Tianshui to get the information of which genes can be used in the future。We got following results and summaries:1) Among the 494 materials, only 50 (10.1%) cultiavars resistant to both CYR32 and CYR33 during seeding stage; 133 (26.9%) cultivars with adult plant resistance; the rest 311 (63%) cultivars without resistance to current races. This means the resistance level of current cultivars is low, and new effective resistance genes should be discovered and brought to breeding. 2) Molecular tests showed most cultivars which with all stage resistance drive from Guinong series and 92R series; So far identification of Yr5 lacking reliable molecular markers; while Yr10 and Yr15 haven't been used; Out of 494 materials, 129 culivars carry Yr9 gene, 45 cultivars carry Yr17 gene; only 10 carry Yr18 gene.3) After evaluating the differential host and known gene cultivars to stripe rust during seeding and adult stage both in Yangling and Tianshui, Yr5,Yr10,Yr15,Yr17,Yr24/Yr26 genes are still effective to stripe rust during all stage; Yr11,Yr12,Yr13,Yr14,Yr16,Yr18,YrSp,YrTr1,YrTr2,YrTye,YrExp1,YrExp2,YrDT are effective adult plant resistance genes.