Molecular Marker And Genetic Analysis Of Baihulu And Dahongtou With Powdery Mildew Resistance

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important wheat disease, especially in areas with a cool and humid climate. Growing of resistance cultivars is one of the most economical, environmentally safe and effective methods for controlling the disease. Dahongtou and Baihulu are two landraces of Chinese wheat; they still show a wide spectrum resistance to powdery mildew.Subunits composition of high molecular weight gluten in Baihulu and Dahongtou were analyzed by means of SDS-PAGE. The result showed that HMW glutenin subunits of Baihulu and Dahongtou were N,7+8,2+12 and 1,7+8,2+12 respectively.To definitude genetic effects and gene loci of powdery mildew resistance gene in Chinese wheat landrace Baihulu, conventional analysis and SSR technology were used to analyze heredity and molecular markers of the resistance gene.The results showed that F1 of Baihulu×Huixianhong and Baihulu×Shaanyou225 were highly resistant to powdery mildew. The ratios of resistant plants to susceptible plants in F2 generation were 118∶4 2 and 112∶3 8, respectively. The segregation ratio fitted expected 3∶1, so it suggested that powdery mildew resistance of Baihulu was controlled by a dominant gene. By SSR analysis with 208 pairs of primers, only one marker Xgwm337 was detected polymorphic DNA fragments between the resistant and susceptible pools, this marker was further identified, which linked to powdery mildew resistance gene with genetic distance 4.60cM in Huixianhong×Baihulu F2 populations. The powdery mildew resistance gene,temporarily designated as mlbhl,was located on chromosome 1D by using Chinese Spring nullisomic-tetrasomics.Conventional genetic analysis and SSR technology was used to analyze genetic effects and gene locations of resistant gene to powdery mildew in wheat Dahongtou. The results showed that F1 of Dahongtou×Shaan160 were highly resistant to powdery mildew. The ratios of resistant plants and susceptible plants in F2 generation were 121∶91. The segregation ratio fitted expected 9:7 so it suggested that powdery mildew resistance of Dahongtou was controlled by 2 dominant complementary genes. By SSR analysis with 208 pairs of primers, one marker Xgwm337 generated polymorphic DNA fragments between the resistant and susceptible plants DNA pools. The powdery mildew resistance gene was located on chromosome 1D by using Chinese Spring nullisomic-tetrasomics.