Abstract
It has previously been reported on a hybrid corn named Tomorokoshi Ko No. 7 planted at various dates that heat-unit accumulations in the effective degrees required for silking from planting and for maturity after silking were 807°C and 786°C, respectively, when a daily mean temperature from 10°C to 25°C was designated as the effective degrees for silking and from 1°C to 23°C, for maturity after silking, and that they were assumed to be constant regardless of planting dates. The present investigation was undertaken to see if the heat-unit accumulations in the effective degrees presented in the previous paper would be applied to corn planted in different years and at different locations. During each period from planting to silking and from silking to maturity, there were no-differences at the 5 % level of significance between the group means of the heat-unit accumulations in the effective degrees at the various planting dates and in the different years or at the different locations. From the above facts, it may be concluded that the heat-unit accumulations in the effective degrees required for silking and for maturity after silking were assumed to be constant regardless of years and locations.
