Abstract
The number of tillers appearing before snow determine the ratio of effective tillers and yield in winter wheat in Hokkaido. This study investigated the varietal difference in the effect of tillering time on ear formation and yield using ”Kitahonami”, ”Yumechikara” and ”Kitami91”, which are winter wheat varieties in Hokkaido. In the tillers with more than two leaves just before snow (robust stems before wintering,RS), the ratio of effective tillers was 91% in Kitahonami, 81% in Yumechikara, and 76% in Kitami91. In the tillers that appeared in spring after the snow melted, ears were not formed in these three varieties. We investigated the stem length and the ear length of effective tillers in the three varieties, RS with effective tillers had longer stems and ears than the other stems. At harvest, grain weight per ear, grain number per panicle and 1000-grains weight on RS were significantly greater than on the other stems. We concluded that tillers appeared in spring do not form ears, and only the tillers that appeared before winter would determine the number of ears per plant and grains per ear, and thus the yield of winter wheat in Hokkaido.
