Breeding for Competitive and High-Yielding Crop Cultivars

Weed control with herbicides is not possible in several systems including control of wild oat (Avena fatua L.) in tame oat (Avena sativa L.), red rice (Oryza sativa L. var. sylvatica) in rice (Oryza sativa L.), and in organic systems. Competitive crop cultivars can be used to manage weed competition if selective weed control by herbicides is not possible. However, most existing competitive crop cultivars often have low weed-free yield and poor grain quality. We hypothesize that the progeny of a cross between a competitive for-age-type oat cultivar and a high-yielding and high grain quality grain oat cultivar will have high yield and good grain quality as well as high competitive ability (CA). The objective of this study was to evaluate progeny lines from a cross between a tall, competitive, forage-type oat cultivar with a semidwarf, high-yielding milling oat for their CA against wild oat. A field study was performed in two locations in Saskatoon, SK, Canada, in 2008 and 2009 using seven progeny lines and the two parents. Oat was seeded with and without wild oat at a target crop and weed density of 250 plant m (2) in a randomized block design with four replicates. All the genotypes were high yielding and did not differ in grain yield or quality either in weed-free or weedy conditions. Some of the tall (CDC Baler, SA050498, and SA050479) and short (SA050040 and Ronald) genotypes had high average grain yield under both weed-free and weedy conditions compared with the other genotypes. The tall oat line SA050479 was among the most weed suppressive, which resulted in less wild oat biomass. The seedling total leaf area, crop height, and the seedling third leaf area were negatively correlated with wild oat biomass. This study demonstrates that a cross between a high-yielding and a highly competitive genotype can result in progeny with high CA, yield, and crop quality.