Gene Analysis For Stripe Rust Resistance In Chinese Commercial Wheat Cultivars

Wheat stripe(yellow) rust caused by Puccinia striiformis f.sp.tritici(PST), continuously threaten the wheat production in China particularly when the climate is favorable to the occurrence of the disease.Breeding and release of resistant cultivars against stripe rust is an economical and effective measure to the control of disease. However genes for stripe rust resistance in Chinese commercial cultivars are still unkown.So it is imperative to definitude existence of genes for stripe rust resistance in major wheat cultivars and advanced lines in China,which could provide useful aid to gene deployment and breeding cultivars with stripe rust resistance.Based on gene for gene theory,33 isolates of Puccinia striiformis f.sp.tritici (Pst)with different avirulence/virulence gene combination from 16 countries were used to postulate the present of Yr genes in 102 Chinese wheat cultivars including 49 predominant cultivars,and 53 newly released cultivars.Identification of adult plant resistance was also conducted in the field using two dominant pathotypes of Pst namely CYR32 and Su11-14.The results indicated that genes Yr1,Yr2+Yr+3Yr4,Yr3+Yr6+,Yr3b+Yr4b+,Yr5,Yr6,Yr7,Yr9,Yr17,Yr26,YrAlba,YrAnza,YrSD,YrSp,either alone or in combination were postulated in55cultivars,whereas known Yr genes were not detected in the other 47cultivars.The resistance genes Yr9 were found in 36 cultivars such as shi4185,Jingdong 8,han6172etc;Yr1 were detected in 6 cultivars such as Yumai 18,huaimai20,lantian10etc;5 cultivars may contain Yr17 such as Yuarni 47 etc; Yr3b+Yr4b was found in combination with Yr9 in Zhoumai17,A3-5;Wanmai50, Qinnong142carried YrAlba,and YrSD were found in Qinnong142,Xinmai11;Yr26 were found in Chuanmai42,Zhongliang 99293 and Lantian17;Han4546 and tian9633-5were postulated to possess Yr2+Yr3+Yr4 combination;YrAnza was found in Wanmai38,,Yr7 and Yr6 were found in Chuanmai39,Yr3+Yr6 was found in Yumai47,Yr5 was found in Lantian22;YrSp was found in Zhongliang 200192.Identification of stripe rust resistance in the field indicated that 17 wheat cultivars of Chuanmai 42,Zhoumai 1,Chang4640,BainongAK58,Qinnong142,Lantian17, Lantian18,Lantian19,Lantian20,Lantian22,Lantian23,Zhongliang26,Zhongliang 200192,Zhongliang 958,A3-5,Tian9633-5 displayed good resistance to both dominant pathotypes of Pst CYR32 and Su11-14 in the adult plant stage,and 14 wheat cultivars of Wanmai 39,Wanmai 48,Xinmai 18,Jimai 21,Heng5229, Chuannong19,Zhoumai18,Lantian11,Lantian 12,Lantian 14,Lantian 15,Lantian 21,Zhongliang 22 and Zhongliang 25 resistant to CYR 32,and 4 wheat cultivars of Lumai 23,8901—11,Wanmai 38,Yangmai 17 resistant to Su11-14,while the rest 67 cultivars represented susceptible to both pathotypes.It concluded that most of Chinese commercial cultivar are susceptible to stripe rust at present.