Submitted to: Washington State University College of Agriculture and Home Economics
Publication Type: Abstract Only
Publication Acceptance Date: 8/20/2008
Publication Date: 8/20/2008
Citation: Poole, G., Nicol, J., Paulitz, T.C., Campbell, K. 2008. Evaluation of Methods for Assessing Resistance to Fusarium Crown Rot in Wheat. Washington State University College of Agriculture and Home Economics. Page 38.
Technical Abstract: Crown rot, caused by a complex of Fusarium species, of which F. pseudograminearum and F. culmorum are the most important, reduces wheat yields in the PNW by an average of 35%. Breeding for resistance requires adequate Fusarium screening systems. One common barrier in Fusarium screening is the large degree of variation in disease infection. The objective of the research was to find the inoculation method with the greatest consistency and least variation. Experiments to assess the pathogenicity of five PNW isolates of F. pseudograminearum and the best method of inoculation were conducted during 2007 and 2008. Several genotypes that differed for resistance were planted in cone-tainers in growth chambers and the WSU plant growth facility. Five Fusarium isolates were evaluated using five different inoculation methods. Experiments revealed that two Fusarium isolates, one collected in Oregon and one collected in Washington, were consistently the most pathogenic across studies. The inoculation method that produced the most consistent results in pathogenicity and differentiation between resistant (‘2-49’) and susceptible (‘Seri’) wheat genotypes was the agar conidial suspension (106 conidia per µl) placed in a drinking straw at the stem base of seedlings. We will use this inoculation method to evaluate recombinant inbred lines from a cross between the Fusarium tolerant Australian cultivar Sunco and the PNW adapted susceptible cultivar Macon. Through this we will identify specific gene regions (QTL) associated with resistance that will allow us to use marker assisted selection as well as controlled growth chamber evaluation of breeding lines and cultivars. We have also established a screening trial in the field at Lind and in a sand bed on the WSU campus in order to evaluate resistance on adult plants, over the whole growth cycle.