Breeding for Root Lesion Nematode Resistance in Montana Winter Wheat.

Root lesion nematodes (Pratylenchus spp.) present a serious challenge to dryland wheat production worldwide. Development of resistant cultivars would provide great economic benefit to growers. From 2012-2013, a set of backcross lines (MT08185//MT08184/Persia 20) was screened twice for resistance to P. neglectus. Progeny and parent lines were grown in infested soil for 16 weeks. Nematodes were then extracted from roots of individual plants and counted to obtain per plant final populations. ANOVA results from the 2013 screen showed significant differences in mean P. neglectus populations among lines (p<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 2013 field trial in the absence of root lesion nematodes indicated reductions in grain yield, volume weight, and protein were not associated with resistance. Identification of QTL for resistance to root lesion nematodes will facilitate marker-assisted introgression of resistance genes in a backcross-breeding program. Single marker analysis of 104 genome-wide SNPs was performed to identify genomic regions associated with resistance to P. neglectus.  The analysis identified putative marker-trait associations on chromosomes 1A, 1D, 2B, 5B, 5D, 7A and 7D (all p<0.05).  These potential QTL regions will be tested in analysis of phenotypic and genomic data obtained from 200 BC₁F₃ (MT08185//MT08184/Persia 20) progeny, and 228 F₂ progeny derived from a separate cross (Persia 20/McNeal).