Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2009
Publication Date: August 1, 2009
Citation: Castell-Miller, C.V., Samac, D.A. 2009. Population Genetic Structure of Cochliobolus miyabeanus on Cultivated Wild Rice (Zizania palustris L.) in Minnesota [abstract]. 2009 American Phytopathological Society Annual Meeting, August 1-5, 2009, Portland, Oregon. Available: http://www.apsnet.org/meetings/2009/abstracts/a09ma108.htm. Technical Abstract: Cochliobolus miyabeanus (Bipolaris oryzae) is the causal agent of fungal brown spot (FBS) in wild rice (Zizania palustris L.), an aquatic grass, endemic in Minnesota, Wisconsin, and parts of Canada. Grain yield losses can reach up to 74% when the disease starts at the boot stage and continues until grain maturity. In Minnesota, management of FBS in grower paddies is done mostly by sanitation and application of fungicides. Breeding for resistance is in progress. Knowledge of the amount and distribution of fungal diversity is required for an integrated management system of FBS. The fungus, an ascomycete, is believed to be genetically diverse but no data are available yet. A collection of 200 isolates was made from Polk, Clearwater, Aitkin, Beltrami, Itasca, and Lake of the Woods counties during 2007 and 2008. Analysis of amplified fragment length polymorphism (AFLP) markers from 93 isolates with 17 polymorphic markers, generated with two primer-pair combinations, indicate a total average gene diversity (H) of 0.34 and low, although significant, population subdivision by area of collection (Fst = 0.14, P = 0.0). H values within areas of collection were different. Forty-three haplotypes were present among 93 isolates. These preliminary results indicate that the population of C. miyabeanus in Minnesota is genetically diverse.