Abstract
Orchardgrass clones collected from Nemuro and Sapporo areas were evaluated on the field of Konsen Agr. Exp. Sta. at Nakashibetsu-cho in the eastern area in Hokkaido. Date of heading, plant height, number of panicules and green yields (the 1st crop, regrowth and their total) were measured under clonal line plots over 4 years from the 2nd year to the 5th year after the experimental plots had been established. The results may be summarized as follows. 1) Green yield of the 1st crop of Nemuro group was higher than Sapporo group, but regrowth yield of the former was lower than the latter. 2) The genetic variations, h^2 and G.C.V., within Nemuro group were smaller than that within Sapporo group on most of the characters. 3) Several parameters estimating the repeatability of characters through years or seasons, h_r^2, r_g and σ_<gy>/σ_g, as defined in the notes of table 2, showed that Nemuro group had higher stability for yearly different conditions than Sapporo group. 4) Higher yielding clones within Nemuro group showed relatively lower regression coefficient and standard deviation from regression than those within Sapporo group. But some clones of Sapporo group had higher yielding potentials with higher stability. It was supposed that the climatic conditions of the eastern area are effective for primary screening of clones in the orchardgrass breeding programs.
