Department of Horticultural Sciences

Collaborators (Cornell): R. Provvidenti, M. Tonguc, A.G. Taylor, W.B. Boone

The primary goal of the pea breeding program is to develop commercial quality germplasm in which numerous disease resistance genes have been incorporated. Several different habit types are being developed (dwarf, semileafless, and edible podded). We rely heavily on marker-assisted selection to identify in early generations those genotypes possessing all of the desired resistance genes.

Resistance or tolerance to three fungal diseases, powdery mildew, fusarium wilt, and common root rot, is a high priority. Molecular markers are available for at least one gene, er-1, that confers a high level of tolerance to powdery mildew. Markers have also been identified for two of the genes affecting tolerance to common root rot. At present, markers are not available for either wilt or near-wilt resistance, and we screen for these genes by direct inoculation or field grow-outs in collaboration with Dr. Fred Muehlbauer in Pullman, Washington. We are also closely examining the genetic basis of common root rot tolerance in the lines MN313 and MN314 because these appear to give particularly high levels of tolerance to the Aphanomyces strain being used in our experiments. This work is being done in collaboration with Dr. Craig Grau at the University of Wisconsin.

Five virus resistance genes [mo (bean yellow mosaic virus), En (pea enation mosaic virus), sbm-1 (pea seedborne mosaic virus), cyv-1 (clover yellow vein virus) and lr (leaf roll virus)], are also being selected for in breeding lines. Dr. Provvidenti has developed direct screens for most of the virus resistance genes, but DNA markers are available for all except the last, and a collaboration among Dr. Rich Larson (Prosser, Washington), Dr. Muehlbauer and our program should identify a marker for lf this year.

We currently have approximately 40 lines possessing four of the virus resistance genes (mo, En, sbm-1, and cyv-1) and three of the fungal resistance genes (er-1, Fw and Fnw). These lines are all dwarf with normal leaves and pod type. They are of reasonable commercial type with green cotyledons and wrinkled seeds and are available upon request to public and private breeders.