Project Number: 5442-21220-023-54
Project Type: Specific Cooperative Agreement

Start Date: Jun 01, 2008
End Date: May 31, 2009

Objective:
Determine genetic variation of S. sclerotiorum from soybean, sunflower, canola, dry bean, pea and lentil in the northern part of the North Central region using DNA fingerprinting and mycelial compatibility groups. Characterize the virulence of selected isolates on partially resistant and susceptible cultivars of soybean, sunflower, canola, dry bean, pea and lentil.

Approach:
Sclerotinia sclerotiorum is one of the most important pathogens of field crops in the North Central USA, causing economic losses in the numerous susceptible crops grown in the northern tier of states. The diseases caused by this pathogen have been very difficult to control. There is no published information on the genetic variation of S. sclerotiorum in the North Central region of the United States that includes information on isolate virulence across crops such as soybean, sunflower, canola, drybean, pea and lentil. Understanding the genetic variation and virulence of the current isolates of S. sclerotiorum in the region is a fundamental part of the overall strategy of using resistance or other controls for this pathogen. Such information may also help explain the mixed results of field screening for resistance that has been observed over the region and the lack of correlation between field and laboratory evaluations. This research will study genetic variation and virulence of a set of isolates from the current population of the pathogen on dry bean, canola, soybean, sunflower, pea and lentil in the northern tier of states in the North Central Region. This region has the greatest concentration of the numerous crops susceptible to white mold. The primary approach is to make a collection of isolates of the pathogen from the six crops, identify mycelial compatibility groups, use microsatellites to characterize the genetic variation and then characterize virulence of isolates representative of the clones/genetic groups on all six crops using two different methods. Two techniques will be employed to evaluate virulence: 1) a novel technique of measuring fungal biomass in infected tissue and 2) a standard cut stem inoculating method which measures lesion length as criteria for virulence. This research will answer some fundamental questions on the biology of this pathogen as it pertains to six important crops grown in a region where Sclerotinia diseases commonly occur.