Genetic analysis of resistance to powdery mildew on 7Mg chromosome of Wheat–Aegilops geniculata,development and utilization of specific molecular markers

Abstract

Background: Blumeria graminis f. sp. Tritici (Bgt) is prevalent in the main wheat-producing regions of China and result in serious yield losses in recent years. Breeding resistant cultivars is the most environmentally sound measure of disease control. Aegilops geniculata Roth, a close relative of common wheat, is an important and valuable disease resistance gene donor for wheat improvement.Results: In this study, to validate powdery mildew resistance on chromosome 7Mg, two genetic populations were constructed and analyzed. Wheat – Ae. geniculata 7Mg disomic addition line and 7Mg (7A) alien disomic substitution line crossed with susceptible Yuanfeng175 of susceptible powdery mildew respectively to form generations F1 and F2. Cytological examination, in situ hybridization (ISH), and functional molecular markers analysis showed that alien chromosomes could be inherited stably, produce different gamete types and enrich the intermediate materials for wheat genetic variation. The populations were inoculated with the physiological race E09 of powdery mildew at seedling stage. The results revealed that the plants showed high resistance to powdery mildew with chromosome 7Mg. Besides, more specific markers were developed to verify chromosome 7Mg resistance based on SLAF-seq technique. Then, 84 specific molecular markers were obtained about chromosome 7Mg. Among them, four markers were selected randomly to checked in two genetic populations. In summary, the above analysis confirmed that a dominant high powdery mildew resistance gene inherited were located on the chromosome 7Mg of Aegilops geniculate. Conclusions: The results provide a basis for resistance gene mapping and specific marker development in future.