The effect of oat (Avena sativa L.) genotype and plant population on wild oat (Avena fatua L.) competition

The inability to control wild oat (Avena fatua L.) in oat (Avena sativa L.) crops by chemical means limits growers to the use of cultural control methods. Delayed seeding is the most commonly used measure; however, both crop yield and quality may suffer as a result. The objectives of this research were to i) determine if western Canadian oat genotypes differ in competitive ability, ii) determine the effect of increased plant populations on oat – wild oat competition, iii) determine the effect of wild oat competition on oat quality, and iv) establish whether or not oat genotype and seed size affect germination characteristics under low temperature and moisture stress. These objectives were tested using field and laboratory experiments. Morphologically diverse oat genotypes differed in their ability to both tolerate wild oat competition and interfere with wild oat growth. Although low yielding under weed-free conditions, when subject to wild oat competition CDC Bell was able to maintain yield, reduce wild oat seed production and was the most competitive of the genotypes examined. Increased plant populations achieved through higher seeding rates provide an effective means by which to enhance the competitive ability of oat genotypes resulting in reduced yield loss and wild oat seed production. With the exception of the percentage of wild oat seed in harvested oat samples, wild oat competition had minimal effect on oat quality. Differences in germination characteristics were observed among the genotypes examined. Conclusions that emerge from this research are that i) oat genotypes differ in their ability to tolerate and interfere with wild oat competition, ii) increased plant populations may provide a long-term control measure that may reduce weed seed contribution to the soil seedbank as well as enhance the competitive ability of oat, iii) wild oat competition has minimal effect on milling oat quality with the exception of percentage of wild oat seed in harvested samples and iv) that median germination time varies among oat genotypes.