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Identification of quantitative trait loci for resistance to two species of root-lesion nematode (Pratylenchus thornei and P. neglectus) in wheat

Zwart, R.S. and Thompson, J.P. and Godwin, I.D. (2005) Identification of quantitative trait loci for resistance to two species of root-lesion nematode (Pratylenchus thornei and P. neglectus) in wheat. Australian Journal of Agricultural Research, 56 (4). pp. 345-352.

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Article Link(s): http://dx.doi.org/10.1071/AR04223

Publisher URL: http://www.publish.csiro.au/

Abstract

Pratylenchus thornei and P. neglectus are two species of root-lesion nematode that cause substantial yield losses in wheat. No commercially available wheat variety has resistance to both species. A doubled-haploid population developed from a cross between the synthetic hexaploid wheat line CPI133872 and the bread wheat Janz was used to locate and tag quantitative trait loci (QTLs) associated with resistance to both P. thornei and P. neglectus. Wheat plants were inoculated with both species of nematode in independent replicated glasshouse trials repeated over 2 years. Known locations of wheat microsatellite markers were used to construct a framework map. After an initial single-marker analysis to detect marker-trait linkages, chromosome regions associated with putative QTLs were targetted with microsatellite markers to increase map density in the chromosome regions of interest. In total, 148 wheat microsatellite markers and 21 amplified fragment length polymorphism markers were mapped. The codominant microsatellite marker Xbarc183 on the distal end of chromosome 6DS was allelic for resistance to both P. thornei and P. neglectus. The QTL were designated QRlnt.lrc-6D.1 and QRlnn.lrc-6D.1, for the 2 traits, respectively. The allele inherited from CPI133872 explained 22.0-24.2% of the phenotypic variation for P. thornei resistance, and the allele inherited from Janz accounted for 11.3-14.0% of the phenotypic variation for P. neglectus resistance. Composite interval mapping identified markers that flank a second major QTL on chromosome 6DL (QRlnt.lrc-6D.2) that explained 8.3-13.4% of the phenotypic variation for P. thornei resistance. An additional major QTL associated with P. neglectus resistance was detected on chromosome 4DS (QRlnn.lrc-4D.1) and explained a further 10.3-15.4% of the phenotypic variation. The identification and tagging of nematode resistance genes with molecular markers will allow appropriate allele combinations to be selected, which will aid the successful breeding of wheat with dual nematode resistance.

Item Type:Article
Business groups:Agri-Science, Crop and Food Science
Additional Information:Reproduced with permission from © CSIRO Publishing. Access to published version may be available via Publisher’s website.
Keywords:Composite interval mapping; doubled haploids; synthetic hexaploid wheat; disease resistance; Pratylenchus neglectus; Pratylenchus thornei; Triticum aestivum.
Subjects:Science > Biology > Genetics > Quantitative genetics (esp. Quantitative Trait Loci (QTL) articles)
Plant pests and diseases > Individual or types of plants or trees > Wheat
Plant pests and diseases > Weeds, parasitic plants etc
Deposited On:05 Mar 2009 06:58
Last Modified:26 Oct 2011 05:24

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