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Molecular mapping of cereal cyst nematode resistance in Triticum monococcum L. and its transfer to the genetic background of cultivated wheat

Singh, Kuldeep, Chhuneja, Parveen, Singh, Inderjit, Sharma, S. K., Garg, Tosh, Garg, Monika, Keller, Beat, Dhaliwal, Harcharan S.
Euphytica 2010 v.176 no.2 pp. 213-222
alleles, durum wheat, Heterodera avenae, major genes, pest resistance, quantitative trait loci, marker-assisted selection, genetic resistance, plant pests, Triticum aestivum, phenotypic variation, wild relatives, introgression, chromosomes, chromosome mapping, plant genetic resources, inbred lines, Triticum turgidum subsp. durum, plant breeding, Triticum monococcum subsp. aegilopoides, cyst nematodes
Triticum monococcum, the diploid A genome species, harbours enormous variability for resistance to biotic stresses. A spring type T. monococcum acc. 14087 was found to be resistant to Heterodera avenae (cereal cyst nematode, CCN). A recombinant inbred line population (RIL) developed by crossing this accession with a CCN susceptible T. boeoticum acc. 5088 was used for studying the inheritance and map location of the CCN resistance. Based on composite interval mapping two QTL, one each on chromosome 1AS and 2AS, were detected. The QTL on 1A, designated as Qcre.pau-1A, appeared to be a major gene with 26% contribution to the overall phenotypic variance whereas the QTL on 2A designated as Qcre.pau-2A contributed 13% to total phenotypic variation. Qcre.pau-1A is novel, being the only CCN resistance gene mapped in any ‘A' genome species and none of the other known genes have been mapped on chromosome 1A. The QTL Qcre.pau-2A might be allelic to Cre5, a CCN resistance gene transferred from Ae. ventricosa and mapped on 2AS. The Qcre.pau-1A was transferred to cultivated wheat using T. durum cv. PBW114 as the bridging species. Selected CCN resistant F₈ lines showed introgression for the molecular markers identified to be linked with CCN resistance locus Qcre.pau-1A. Thus, this gene alone could impart complete resistance against CCN. These introgression lines can be used for marker-assisted transfer of Qcre.pau-1A to elite wheat cultivars.