Evaluating the effect of allelopathy on timothy (Phleum pratense L.) competitive ability against reed canarygrass (Phalaris arundinacea L.)

Abstract

There is increasing interest in improving the competitive ability of timothy (Phleum pratense L.) against rhizomatous grass weeds such as reed canarygrass (Phalaris arundinacea L.) through breeding for long-term maintenance of high-quality vegetation in timothy-based grasslands. This study aimed to quantify the effect of allelopathy on timothy’s competitive ability against reed canarygrass in field conditions using 10 timothy genotypes and reed canarygrass (cv. Palaton) by an agar-based method and field tests in Kunneppu, Japan. The resistance of timothy according to shoot length in the agar-based method explained 40.0% of the variance of timothy total dry matter yield for three years under weedy condition in field tests. The potential allelopathic activity of timothy against reed canarygrass shoot and root length in the agar-based method explained 58.7% and 84.7% of the variance in reed canarygrass total dry matter weight for three years and infested reed canarygrass total dry matter weight on bare ground in the third year, respectively, under weedy condition in field tests. Canonical discriminant analyses selected the abovementioned three traits related to allelopathy against reed canarygrass as significant factors associated with timothy yield and reed canarygrass weight. These important findings suggest that breeding improvement of allelopathy could improve the competitive ability of timothy.