Optimising initial population density, growth time and nitrogen nutrition for assessing resistance of wheat cutivars to root-lesion nematode (Pratylenchus thornei)

Thompson, J. P. and Clewett, T. G. and O'Reilly, M. M. (2015) Optimising initial population density, growth time and nitrogen nutrition for assessing resistance of wheat cutivars to root-lesion nematode (Pratylenchus thornei). Australasian Plant Pathology, 44 (2). pp. 133-147. ISSN 0815-3191

Abstract

Pratylenchus thornei is a major pathogen of wheat in Australia. Two glasshouse experiments with four wheat cultivars that had different final populations (Pf) of P. thornei in the field were used to optimise conditions for assessing resistance. With different initial populations (Pi) ranging up to 5250 P. thornei/kg soil, Pf of P. thornei increased to 16 weeks after sowing, and then decreased at 20 weeks in some cultivar x Pi combinations. The population dynamics of P. thornei up to 16 weeks were best described by a modified exponential equation Pf(t) = aP ie kt where Pf(t) is the final population density at time t, Pi is the initial population density, a is the proportion of Pi that initiates population development, and k is the intrinsic rate of increase of the population. The cultivar GS50a had very low k values at Pi of 5250 and 1050 indicating its resistance, Suneca and Potam had high k values indicating susceptibility, whereas intolerant Gatcher had a low value at the higher Pi and a high value at the lower Pi. Nitrate fertiliser increased plant growth and Pf values of susceptible cultivars, but in unplanted soil it decreased Pf. Nematicide (aldicarb 5 mg/kg soil) killed P. thornei more effectively in planted than in unplanted soil and increased plant growth particularly in the presence of N fertiliser. In both experiments, the wheat cultivars Suneca and Potam were more susceptible than the cultivar GS50a reflecting field results. The method chosen to discriminate wheat cultivars was to assess Pf after growth for 16 weeks in soil with Pi~1050–5250 P. thornei/kg soil and fertilised with 200 mg NO3–N/kg soil.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version due to publisher copyright policy.
Faculty / Department / School: No Faculty
Date Deposited: 08 May 2015 02:43
Last Modified: 30 Jun 2016 03:23
Uncontrolled Keywords: nematode population density, growing time, nitrogen nutrition, vertosols, modified exponential growth curve
Fields of Research : 06 Biological Sciences > 0603 Evolutionary Biology > 060307 Host-Parasite Interactions
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
Identification Number or DOI: 10.1007/s13313-015-0347-6
URI: http://eprints.usq.edu.au/id/eprint/27212

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