Genetic improvement and agronomy for enhanced wheat competitiveness with weeds

The rapid development of herbicide resistance in weeds, and environmental i mperatives, have forced the consideration of non-chemical tactics such as c rop competition for weed management. This review of wheat-weed competition examines the plant traits associated with wheat competitiveness, and the op portunities for plant breeding or manipulating crop agronomy to differentia lly favour the growth of the crop. Many studies have proven that enhancing crop competitive ability can reduce weed seed production and crop yield los s, although a number of difficulties in conducting this research are identi fied and suggestions are made for improvement. It remains to be seen whethe r crop competitiveness will be considered as a priority by farmers and plan t breeders. Farmers require precise information on the reliability of agron omic factors such as increased crop seeding rate or choice of variety for e nhancing crop competitive ability in different environments. Plant breeders need to know which plant traits to incorporate in varieties to increase co mpetitive ability. A thorough analysis of the benefits and costs of enhanci ng wheat competitiveness is needed. Competitive wheat crops should be avail able as part of reliable and economical integrated weed management packages for farmers.