Evaluating wheat for tolerance and resistance to root-lesion nematodes

Thompson, J. P. and Clewett, T. G. and Sheedy, J. G. and Seymour, N. P. (2008) Evaluating wheat for tolerance and resistance to root-lesion nematodes. In: 5th International Congress of Nematology (5ICN 2008): Nematodes Down Under, 13-18 Jul 2008, Brisbane, Australia.

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Root-lesion nematodes are estimated to cost the Australian wheat industry AUD$260 million/year. Pratylenchus thornei is the dominant species in the north and P. neglectus in the
south and west. We have tested wheat lines for tolerance to P. thornei on a dedicated 10-ha site of vertisolic soil near Jondaryan 170 km west of Brisbane. The site has been managed in a 4-year rotation of fallow-sorghum-wheat-wheat test plots, such that 2.5 ha are available each year with high P. thornei population and negligible other soil-borne wheat pathogens.
About 2000 early-generation wheat lines are sown in unreplicated plots of 3 rows each 5 m long which are rated twice during the growing season for symptoms of nematode damage. Pre-release lines and varieties for the northern region are sown in plots of 7 rows by 8 m long in replicated experiments on two sowing dates. Yield of the lines/varieties determined from machine harvest is expressed as percentage of site mean yield (SMY) and averaged across trials and years. Tolerance indices derived from SMY have proved very predictive of varietal yield at independent sites infested with P. thornei, and are published annually in extension brochures. Resistance of wheat lines against P. thornei and P. neglectus has been assessed in replicated glasshouse experiments. The wheat lines are tested in pots of vertisolic soil inoculated with cultured nematodes and grown with optimum nutrition, water supply and temperature for nematode multiplication. After 16 weeks, nematodes are extracted from roots and soil from the bottom half of the pot and enumerated under a compound microscope.
These methods have been used successfully to: (1) identify sources of resistance in wild relatives, landrace and synthetic hexaploid wheats, (2) characterise breeders' lines and varieties for resistance, (3) screen segregating progeny from backcross and topcross programs, and (4) characterise mapping populations for development of molecular markers to resistance genes.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 18 Jun 2014 05:27
Last Modified: 08 Dec 2015 05:55
Uncontrolled Keywords: Darling Downs; nematodes; wheat
Fields of Research : 06 Biological Sciences > 0604 Genetics > 060412 Quantitative Genetics (incl. Disease and Trait Mapping Genetics)
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070305 Crop and Pasture Improvement (Selection and Breeding)
Socio-Economic Objective: B Economic Development > 82 Plant Production and Plant Primary Products > 8205 Winter Grains and Oilseeds > 820507 Wheat
URI: http://eprints.usq.edu.au/id/eprint/25316

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