Germination, Elongation, Emergence and Establishment under Low Temperature Conditions in the Rice Varieties Bred at Tohoku Agricultural Research Center

Abstract

Germination, elongation, emergence and establishment under low temperature conditions in 18 rice varieties including 8 varieties bred at Tohoku Agricultural Research Center (TARC) were evaluated. Most of the varieties were considered to show dormancy since the days to germination (DG) was shortened by dry heat treatment. When dormancy was weak, varietal differences in DG were clear. Under the cold water condition, varietal differences were observed in coleoptile length. The coleoptiles of non- germinated seed elongated earlier in varieties having shorter DG. Even the coleoptiles of germinated seeds elongated earlier in varieties having shorter DG in some cases. Under a submerged condition, varieties having shorter DG showed shorter days for emergence (DE). The varieties having a shorter DE showed a higher rate of establishment especially under the very low temperature condition. These results suggest that the varieties having a shorter DG were superior in establishment. Among the varieties used, “Arroz da Terra”, “Ta Hung Ku” and “Himenomochi” had shorter DG and were superior in establishment. Among the varieties bred in TARC, varieties for cooking, “Moeminori”,“Eminoaki”, and “Chihominori”, and a glutinous variety “Tokimekimochi” had a risk of late establishment due to weak dormancy. Forage rice varieties, “Bekoaoaba”, “Iwaidawara” and “Bekogenki” had a slightly longer DG and were slightly inferior in establishment.