2019 Volume 65 Issue 3 Pages 184-194
Breeding cultivars of timothy (Phleum pratense L.) that are competitive against quackgrass (Agropyron repens (L.) Beauv.) and reed canarygrass (Phalaris arundinacea L.) would offer many benefits for farmers. In this study, we investigated the effectiveness of selection under weedy conditions and indirect selection under weed-free conditions. We also investigated the potential simultaneous improvement of competitive ability with other major traits. These trials were conducted using five strains or cultivars under sward conditions and 20 and 25 clonal lines under spaced-plant conditions from 2012 to 2017 in Kunneppu and Shintoku, Japan. In a yield trial under weedy conditions, the total dry matter yield was significantly higher for the progeny of a strongly competitive group than for the progeny of a weakly competitive group. This suggested that the selection of clonal lines under spaced-plant conditions is potentially effective for improving progeny under sward conditions. The mean total dry matter yield was significantly higher for an indirectly selected group than for a non-selected group under weedy conditions, suggesting that indirect selection is a useful screening method. A genetic correlation analysis suggested that continuous crosses among desirable genotypes for lodging resistance, nutritive traits, and competitive ability would be necessary for simultaneous improvement.
