Breeding for root lesion nematode resistance in Montana winter wheat
D. MAY (1), A. Dyer (1), P. Bruckner (1), J. Berg (1). (1) Montana State University - Bozeman, Bozeman, MT, U.S.A.
Root lesion nematodes (<i>Pratylenchus</i> spp.) present a serious challenge to dryland wheat production worldwide. Development of resistant cultivars would provide great economic benefit to farmers. From 2012-2013, a set of backcross lines (MT08185//MT08184/Persia 20) were screened for resistance to <i>P. neglectus</i>. Progeny and parent lines were grown in infested soil for 16 weeks. Nematodes were extracted from roots of individual plants and counted to obtain per plant final populations. ANOVA results from the 2013 screen provided convincing evidence of a difference in mean <i>P. neglectus </i>populations among lines (<i>p<</i>0.01). The median final population of susceptible parent MT08184 was an estimated 4.0 times greater than that of resistant parent Persia 20. A prior screen using inoculum obtained from a different Montana region provided no evidence of a difference in control means, suggesting the existence of pathotypes. A 2013 yield trial provided no evidence of correlation between a line’s average final population and grain yield (<i>R2</i><0.01, <i>p</i>=0.57). Similar results were obtained for test weight, protein, plant height and heading date. Identification of QTL for resistance to root lesion nematodes will facilitate marker-assisted introgression of resistance genes in a backcross-breeding program. To that end, 140 genome-wide SNPs were used to genotype progeny lines, and single-marker analysis was performed to identify genomic regions associated with resistance to <i>P. neglectus</i>.
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