2019 Volume 65 Issue 3 Pages 167-172
Improvement of the competitive ability of timothy (Phleum pratense L.) against quackgrass (Agropyron repens (L.) Beauv.) and reed canarygrass (Phalaris arundinacea L.) through breeding should lead to long-term maintenance of high-quality vegetation in timothy-based grasslands. In this study, we investigated differences in the competitive ability of 20 clonal lines of timothy against quackgrass and reed canarygrass. These evaluations were conducted from 2012 to 2014 in Shintoku, Japan. The dry weight differed significantly among the clonal lines of timothy, and showed moderate to high broad-sense heritability in most harvests. The total dry matter weight (an index of competitive ability), showed a strong genetic correlation between the two weedy conditions. There were also strong genetic correlations between the visual rating of plant vigor in all harvest or regrowth periods and the total dry matter weight. Quackgrass had a lower suppressing effect and lower plant height than reed canarygrass, suggesting that evaluations of competitive ability against quackgrass would be easier than those against reed canarygrass. These results suggested that selection based on growth in quackgrass weedy conditions is potentially useful to improve the competitive ability of timothy, and that the visual rating of plant vigor is an alternative easy method for evaluating yield.
