Abstract
The effects of meteorological factors during grain filling and maturation on pre-harvest sprouting in wheat were examined by glasshouse and field trials for several years using two cultivars with different levels of sprouting tolerance ,‘Norin 61’ (resistant) and ‘Shirogane−Komugi’ (susceptible). The risk of pre-harvest sprouting was evaluated from the percentage of kernels germinated from the spikes detached and incubated for 10 days at 15°C. Germination percentages at harvest time were positively correlated with temperature during maturation in both trials. However, in the field trials there were large variations in germination percentages and the correlation coefficient was smaller than that in the glasshouse trials. A simple statistical correlation analysis revealed that the average temperature from the time with 50％ kernel water content to physiological maturity significantly correlated with pre-harvest sprouting. In addition, germination percentage increased with increasing number of rainy days during that period but there was no significant correlation between germination percentage and total precipitation in Norin 61.These results indicate that the high temperature and prolonged wetness just before rapid decline of kernel moisture increase the potential risk of pre-harvest sprouting.
