Submitted to: Journal of Plant Pathology
Publication Type: Abstract Only
Publication Acceptance Date: June 20, 2008
Publication Date: August 20, 2008
Citation: Okubara, P.A., Steber, C.M., Paulitz, T.C., Kidwell, K.K. 2008. Ems-generated rhizoctonia resistance in an adapted wheat. Journal of Plant Pathology. S.350.(2) Technical Abstract: We report the first genetic resistance in wheat to Rhizoctonia solani AG-8 and R. oryzae, the causal agents of Rhizoctonia root rot and pre-emergence damping-off. Rhizoctonia resistance was generated in the spring wheat cultivar Scarlet using EMS mutagenesis. Resistant plants, named Scarlet-Rz1, displayed substantial root and shoot growth in the presence 100 to 400 ppg of R. solani AG-8 and R. oryzae in greenhouse assays. Scarlet-Rz1 was otherwise indistinguishable from wild-type Scarlet in appearance, growth habit and seed production in the greenhouse and field. Seedling resistance was monitored in the BC1F2, BC1F3, BC2F2, BC2F3 and BC2F4 generations of Scarlet-Rz1, and appeared to be inherited as a single co-dominant gene. Genetic resistance to necrotrophic soilborne pathogens is essential for improving the economic viability of conservation tillage systems, in which damage caused by root pathogens can severely limit yield potential. In the absence of naturally-occurring resistance genes and of effective control practices for Rhizoctonia root rot and damping-off, Scarlet-Rz1 is novel genetic resource for developing other Rhizoctonia-resistant wheat cultivars. Our findings also demonstrate the utility of chemical mutagenesis for generating resistance to necrotrophic pathogens in allohexaploid wheat.