Genetics Analysis And Molecular Mapping Of Stripe Rust Resistance In Wheat Cultivars

Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst), is one of the mostimportant diseases of wheat worldwide. China has the largest andrelatively independentdisease epidemic area.In China, wheat stripe rust mainly occurs in northwestern,southwestern and huanghuai wheat regions. Epidemic of this disease could cause abouttwenty to thirty percent loss on wheat production,even reached to fifty percent if epidemicsevere.It is known that growing resistant cultivars is the most economical,effective andenvironmental approach to control this disease,according to overseas and domesticresearches and production practice.Due to the simplification of disease-resistant wheatcultivars and frequent variation of pathogenic bacteria,less and less wheat cultivars couldresist this disease.The development and deployment of cultivars with genetic resistance is themost effective, economical and environment friendly way to reduce yield losses due to striperusts.1.Using eight Pst races of China including CYR33、CYR32、CYR31、CYR29、CYR17、Su11-4、Su11-7and T4to valuate the fifteen wheat cultivars at the seeding. Five cultivarspresented0to1+, including Tianxuan43,Tianxuan47,99293, Flansers and Guinong22. Sixcultivars presented2to2+,including Tianxuan45, Tianxuan46, Tian98101,Zhongliang2000461and Zhongliang96289. Zhongliang9589was resistant except to CYR32.Zhong4onlyshowed susceptible to T4.2.The crosses between nine cultivars and Mingxian169were separately tested with Pstraces CYR32and CYR33to identify the genetic of stripe rust resistance genes. The resistanceof Tianxuan45to CYR33was controlled by a dominant gene and.two recessive genes. Theresistance of Tianxuan46to CYR33was controlled by a dominant gene. For Tianxuan47, adominant gene and.two recessive genes conferred resistance to CYR33and so was CYR32.For Zhongliang2000461, a dominant gene and a recessive genes conferred resistance toCYR33and two dominant gene conferred resistance to CYR32. The resistance of Tian98101to CYR32was controlled by a dominant gene and the resistance of Zhong4to CYR32wascontrolled by a dominant gene too. The resistance of Guinong22to CYR33was controlled bya recessive gene and the resistance of Flansers to CYR33was controlled by a dominant genetoo. 3.Pst races including CYR32and CYR33were selected to test the F1、F2,and F3generations derived from the cross Tianxuan43/Mingxian169at seedling stage. SSR (simplesequence repeat) markers were used to map the gene conferring resistance to CYR32. Thegenetic analysis showed that one dominant resistance gene to CYR32and one recessiveresistance gene were estimated for Tianxuan43. By using SSR to analyze the150individualsin the F2segregating population, ten markers on chromosome1BS including Xwmc134,Xgwm413, Xbarc187, Xwmc406, Xcfd65, Xgwm18, Xbarc181, Xbarc137, Xwmc419, andXgwm230, were identified to be linked with the resistance gene YrTx43(temporarilydesignated). The two closest linked flanking markers were Xgwm18and Xgwm413withgenetic distances of0.8and3.4cM, respectively. According to origin, chromosome locationand molecular detection, YrTx43could be allelic to stripe rust resistance genes Yr24and Yr26.