Title: Identification of resistance to Rhizoctonia root rot in mutant and wild barley (Hordeum vulgare subsp. spontaneum) Authors
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2013
Publication Date: June 1, 2013
Citation: Ajayi, O.O., Paulitz, T.C., Campbell, K., Murphy, K.M., Ullrich, S.E. 2013. Identification of resistance to Rhizoctonia root rot in mutant and wild barley(Hordeum vulgare subsp. spontaneum). Phytopathology. 103:S2.3. Technical Abstract: Direct seeding cereal crops into non-tilled fields is a practice that is gaining importance in the Pacific Northwest region of the United States. Unfortunately, Rhizoctonia root rot and bare-patch caused by Rhizoctonia solani AG-8 limits the yield of direct-seeded cereals in this region. No resistant germplasm is available, and other available control methods have not been effective in preventing yield losses. To identify potential sources of resistance, M2 populations of two barley lines treated with sodium azide and wild barley (Hordeum vulgare subsp. spontaneum) accessions from the Wild Barley Diversity Collection (WBDC) were evaluated in controlled environments. Ten putative M3 mutants were identified and reciprocal crosses to their wild-type progenitors were carried out for genetic analysis. The findings that not all BC1F1 plants evaluated were susceptible suggest that resistance to Rhizoctonia root rot in the mutant barley is inherited as a dominant trait. Observed segregation ratios of progeny of BC1F1 plants are currently being tested against several gene models of inheritance to determine the number of genes conferring resistance. Of 317 wild barley accessions that were screened for resistance, six accessions showed potential as gene donors for R. solani resistance with one accession, WBDC 021, showing the greatest potential by displaying moderate resistance. Research is underway to test WBDC 021 forits reaction to R. solani under field conditions.