Competitiveness against grass weeds in field pea genotypes

Field pea is an important pulse crop in southern Australia, but its competitiveness against weeds is low. Two experiments were conducted in consecutive years to examine the ability of different genotypes to compete against grass weeds. Field pea was grown in the presence or absence of Lolium rigidum or wheat. In each experiment significant genotypic differences in field pea competitiveness occurred and some genotypes had consistently high or low levels of competitiveness in both years. Tall genotypes generally suppressed L. rigidum and wheat more effectively than short genotypes. Leaf type (conventional, semileafless or tare-leaf) only affected competitiveness before flowering and had no effect on yield loss from weed competition. Maturity had little effect on competitive ability. A genotype x environment analysis for competitive ability showed that there was considerable variation in the response to the level of competition (environment) as well as in mean competitiveness among field pea genotypes. Using wheat as a weed identified genotypic differences in field peas more effectively and more consistently than using L. rigidum . Visual assessment of wheat growth with field pea was strongly correlated with a specific genotype's competitiveness, which may form the basis of a simple field-based screening method for competitive ability.