Inheritance And Mapping Of Powdery Mildew Resistance Gene In Khapli Mutant Mft58

Wheat powdery mildew is a kind of worldwide epiphyte disease caused by Blumeria graminis f.sp.tritici(Bgt).The most safe and efficient way to control this disease is identifying new resistance genes and then utilize in breeding.Khapli is Tetraploid wheat from India.Research showed that Khapli may carry 3 powdery mildew resistance genes.However,only Pm4a on 2AL has been applied to breeding.In order to identify powdery mildew resistance genes other than Pm4a in Khapli,20 isolates preserved in our laboratory were used to analyze the resistance spectrum between Khapli and Pm4a near-isogenic line CI14123.Results showed that Khapli was immune to all isolates,while Pm4a near-isogenic line CI14123 was moderate or high susceptible to 7 isolates.mft58 is a fast neutron mutant of Khapli without Pm4a region and susceptible to Pm4a avirulent isolate.In order to eliminate the possible influence of Pm4a,the F2 population constructed by mft58 and susceptible cultival Zhongyin1320 was identified by isolate Bgt37 which is avirulent to mft58 but can overcome Pm4a.35 of 121 evaluated plants were resistant and 86 were susceptible.This resistance segregation fit the ratio determined by a single recessive resistance gene.We temporarily designate this gene as pmmft58.Molecular marker mapping showed that this gene was delimited to a 2.4 cM interval flanked by CA695634 and TC85381 and co-segregated with SSR marker Xwgrc3865 on chromosome 2BS.The corresponding region in Chinese Spring genome is about 1.4 Mb,which contains 24 high confidence genes.