Incremental crop tolerance to weeds: A measure for selecting competitive ability in Australian wheats
Total reliance on herbicides for weed control is unsustainable with the spread of herbicide resistance and the environmental need to reduce pesticide use. Strongly competitive wheat crops that have high tolerance to weed pressure and therefore maintain high yields in the presence of weeds are a low-cost option for reducing dependence on herbicides. We examined the feasibility of selecting for wheat tolerance to weeds by crossing varieties differing for traits associated with competitiveness. Competitive ability and yield potential must be treated as separate traits for selection. Current measures of crop tolerance to weed competition do not separate the two traits so that selection based on these measures is often synonymous with selection for yield potential rather than pure tolerance. We propose a new measure, termed Incremental Crop Tolerance (ICT) that reflects the incremental yield difference between genotypes associated with tolerance, over and above differences in underlying yield potential.
Keywordscompetitive ability grain yield genotype selection weeds incremental crop tolerance herbicide resistance
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- Brennan, J.P., D. Lemerle & P. Martin, 2001. Economics of increasing wheat competitiveness as a weed control weapon. Contributed paper presented to the 45th Annual Conference of the Australian Agricultural and Resource Economics Society. CD-ROM. Adelaide, Australia: Australian Agricultural and Resource Economics Society.Google Scholar
- Challaiah, O., O.C. Burnside, G.A. Wicks & V.A. Johnson, 1986. Competition between winter wheat (Triticum aestivum) varieties and downy brome (Bromus tectorum). Weed Sci 34: 689–693.Google Scholar
- Cullis, B.R., A.B. Smith & R. Thompson, 2004. Perspectives of ANOVA, REML and a general linear mixed model. In: Proceedings of a symposium to honour the 80th birthday of John Nelder. Imperial College, London.Google Scholar
- Cullis, B.R., A.B. Smith & N.E. Coombes 2005. On the design of early generation variety trials with correlated data. J Agric Biol Stat. In Press.Google Scholar
- Donald, C.M. & J. Hamblin 1976. The biological yield and harvest index of cereals as agronomic and plant breedin criteria. Adv Agron 28: 36–402.Google Scholar
- Gilmour, A.R., B.R. Cullis, B.J. Gogel, S.J. Welham & R. Thompson, 2002. ASReml User Guide. Release 1.0. VSN International Ltd., 5 The Waterhouse St., Hemel Hempstead, HP1 1ES, UK.Google Scholar
- Goldberg, D.E.,1990. Components of resource competition in plant communities. In Perspectives on Plant Competition (Eds. J.B. Grace & D. Tilman), pp. 27–49. New York, USA: Academic Press.Google Scholar
- Heap, I.M., 2004. The International Survey of Herbicide Resistant Weeds, http:// www.weedscience.org, assessed 1st September, 2004.
- Lemerle, D., R.D. Cousens, B. Verbeek & J.A. Fisher, 1994. The potential to breed more competitive wheat varieties. Seventh Assembly, Wheat Breeding Society of Australia, University of Adelaide, pp. 19–21.Google Scholar
- Lemerle, D., B. Verbeek, R.D. Cousens & N.E. Coombes, 1996. The potential for selecting spring wheat varieties strongly competitive with weeds. Weed Res 36: 505–513.Google Scholar
- Mohler, C.L., 2001. Enhancing the competitive ability of crops. In Ecological Management of Agricultural Weeds (Eds. M. Liebman, C.L. Mohler & C.P. Staver). Cambridge, UK: Cambridge University Press.Google Scholar
- Patterson, H.D. & R.Thompson, 1971. Recovery of interblock information when block sizes are unequal. Biometrika, 31: 100–109.Google Scholar
- Reeves, T.G. & H.D. Brooke, 1977. The effect of genotype and phenotype on the competition between wheat and annual ryegrass (Lolium rigidum Gaud.). In Proceedings of the 6th Asian-Pacific Weed Science Society Conference (Eds. M. Soerjani, D.E. Barnes & T.O. Robson), pp. 167–172. Jakarta, Indonesia: Asian-Pacific Weed Science Society.Google Scholar