2017 Volume 62 Issue 4 Pages 181-188
In this study, silage corn cultivars were selected to establish a double cropping system in the southern area of the Kanto Region. Several early-maturity cultivars (relative maturity [RM] 100-115days) and several late-maturity cultivars (RM 120-135) were examined for the first and second cropping, respectively. Dry-matter yield, ripening period, and effective cumulative temperature (ECT) over 10°C required for ripening were compared. The yellow-ripe stage when the dry-matter ratio of the whole plants parts increased to 28% was assumed to be the growth stage appropriate for harvesting. In the first cropping from early April, the very early-maturity cultivars with RM of 100reached the yellow-ripe stage in late July, and required approximately 1,188±33°C of ECT for ripening. On the other hand, in the second cropping from early August, the late-maturity cultivars with RM of 125-135reached the yellow-ripe stage in late November or early December, and required approximately 1,200°C of ECT for ripening. We concluded that the combination of the very early-maturity cultivars (RM100) and the late-maturity cultivars (RM125-135) was suitable for the double cropping system in the area examined.
