Evaluation and genetic dissection of the powdery mildew resistance in 558 wheat accessions

Abstract

Abstract Wheat powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a devasting disease of wheat all over the world, leading to significant yield losses. Host resistance is the most cost-effective and eco-soundly strategy to control this disease. It is certainly significant to assess the resistance level of various wheat germplasms as well as identify their genetic basis for the resistance. In the present study, a total of 558 wheat accessions were evaluated their seedling resistance to powdery mildew and the presence of resistance genes Pm1, Pm2, Pm4, Pm5, Pm6, Pm8, Pm21, Pm24, Pm41, Pm60 and Pm69 using different Bgt isolates and gene specific molecular markers. The results indicated that only 25 out of 558 wheat accessions were resistant to the Bgt isolate E09, suggesting the overall level of powdery mildew resistance of these accessions is inadequate. Further, these 25 accessions showed remarkable different resistance spectrum to extra 25 Bgt isolates and ranged from single to 25 ones. Among them, seven accessions remained resistant to all the tested isolates, indicating these accessions possess genes with broad spectrum resistance. Subsequently, the molecular detection using closely linked/diagnostic marker results showed that 249 accessions could carry only one of the tested Pm genes, 75 carry combined Pm genes and 234 not carry any of tested genes. Pm8 was detected at the highest frequency of 61.45%, whereas Pm5, Pm24, Pm41 and Pm69 were not detected. Notably, for seven accessions resistant to all the 26 tested isolates, Pm21 was detected in four of these wheat accessions, including HengS29, Chang 4640, Xinong 556 and ML728; Pm2 and Pm60 were identified in Emai 18 and Xinmai 296, respectively; no any of tested genes were detected in Emai 16, indicating novel broad spectrum resistant gene(s) might be present in this accession. The information on the evaluation and genetic dissection of the powdery mildew resistance in these 558 wheat accessions can be valuable for the popularization of these accessions and also for the powdery mildew resistance breeding using these accessions.