Discovery of resistance to Pratylenchus neglectus among P. thornei‐resistant Iranian landrace wheats and the introgression of both resistances into advanced breeding lines

Abstract

AbstractRoot‐lesion nematodes (RLNs) Pratylenchus thornei and P. neglectus are globally important pathogens of cereal and pulse crops. These RLNs can occur together in farming systems and must be managed concurrently to minimize substantial yield losses in intolerant crop cultivars. Australian wheat cultivars with resistance to P. neglectus, have either the Rlnn1 resistance gene, which provides a high level of resistance but is linked with yellow flour colour that reduces cultivar marketability for bread production, or QRlnn.lrc‐2B, which provides moderate resistance. We evaluated a collection of 91 P. thornei‐resistant Iranian landrace wheats (ILWs) for their resistance to P. neglectus in four glasshouse experiments to (a) identify genotypes with resistance to both RLNs, (b) determine if any genotypes carried Rlnn1 and/or QRlnn.lrc‐2B and (c) develop ILW‐derived advanced breeding lines (ABLs) with resistance to both RLNs. A factor analytic linear mixed model (FA‐1) that explained 70% of the genetic variation, where the genetic correlations between the experiments ranged from 0.54 to 0.77, was used for the combined analysis of all experiments. Seven P. neglectus‐resistant genotypes were identified, with five that had potentially novel resistance. Subsequently, six breeding lines that were resistant to both RLNs were developed by crossing six ILWs with Australian cultivars and selecting for resistance in each generation. Both the ILWs and ABLs will be valuable genetic resources for wheat breeders to develop cultivars with dual resistance, enabling better management of mixed RLN populations with novel P. neglectus resistance that potentially is not linked with yellow flour colour.