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ARS Home » Research » Publications at this Location » Publication #321262
Title: Identification of novel powdery mildew resistance sources in wheat

Author
item LI, GENQIAO - Oklahoma State University
item Xu, Xiangyang
item Bai, Guihua
item CARVER, BRETT - Oklahoma State University
item HUNGER, ROBERT - Oklahoma State University
item Bonman, John

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2016
Publication Date: 6/15/2016
Citation: Li, G., Xu, X., Bai, G., Carver, B.F., Hunger, R.M., Bonman, J.M. 2016. Identification of novel powdery mildew resistance sources in wheat. Crop Science. 56(4):1817-1830.

Interpretive Summary: Powdery mildew is a globally dominating disease of wheat with a high incidence frequency, and growing resistant cultivars plays an important role in managing this devastating disease. Although a considerable number of powdery mildew resistance genes have been identified, only a small number of them have been widely used in wheat breeding because the majority of known resistance genes originated from wheat relatives, and it may take a few years of breeding to eliminate the undesirable characters associated with resistance genes. The objectives of this study were to evaluate powdery mildew resistance and the underlying genes in U.S. wheat breeding lines, and identify novel powdery mildew resistance sources from a worldwide collection of winter wheat germplasm. Our results suggested that 37.5% of resistant lines released recently in the USA carry the Pm3a gene, indicating the narrow genetic basis of powdery mildew resistance. A set of 1297 landraces and 878 historical cultivars were evaluated for powdery mildew resistance. Of these, 56 and 71 accessions showed homogeneously high and moderate resistance, respectively. In addition, highly resistant plants were identified in 41 heterogeneous germplasm. These resistant accessions were further screened for the presence of Pm3a, Pm3b, Pm3c, Pm3d, Pm3f, Pm8, and Pm17 genes using diagnostic markers, and 20 of them carry a known gene. Genetic diversity analysis on these resistance sources was further conducted to provide guidance for their utilization in wheat breeding. The resistance sources identified in this study can be directly used in wheat breeding, and represent a valuable addition to the known powdery mildew resistance genes. They may greatly broaden the genetic basis of powdery mildew resistance.

Technical Abstract: Powdery mildew is a globally dominating disease of wheat with a high occurrence frequency, and genetic resistance plays an important role in managing this devastating disease. The objectives of this study were to evaluate leaf rust resistance and the underlying genes of breeding lines in the USA, and identify novel powdery mildew resistance sources from a worldwide collection of winter wheat germplasm. Our results suggested that 37.5% of powdery mildew resistant breeding lines released recently in the USA carry the Pm3a gene, indicating the narrow genetic basis of powdery mildew resistance. A set of 1297 landraces and 878 early varieties were evaluated for powdery mildew resistance. Of these, 56 and 71 accessions showed homogeneously high and moderate resistance, respectively. In addition, highly resistant plants were identified in 41 heterogeneous germplasm. These resistant accessions were further screened for the presence of Pm3a, Pm3b, Pm3c, Pm3d, Pm3f, 1AL/1RS, and 1BL/1RS translocation segment using diagnostic markers, and 13 of them carry a Pm3 allele. Another 7 accessions possess the 1BL/1RS translocation fragment. Genetic diversity analysis on these resistance sources was further conducted using a set of 5011 SNP markers, and genetically close accessions were identified. The deployment of genetically distant resistance sources identified in this study in wheat breeding may greatly broaden the genetic base of powdery mildew resistance.