Abstract
The growth and yield in the twice harvesting system (THS) were compared with those in once harvesting system (OHS) of two sugarcane varieties (KRFo93–1 bred for forage use and the leading commercial NiF8 for sugar production). The cumulative effective temperature was the highest in OHS, followed by the 1st crop in THS and the 2nd crop in THS in this order. The growth stage was younger as the cumulative effective temperature was lower in both varieties. The stem length was consistently longer in KRFo93–1 than in NiF8, and the differences in stem length between the two varieties was markedly significant in the initial growth period after ratooning and in the 2nd crops in THS including low temperature period. Fresh- and dry-matter yields averaged in the 1st and 2nd ratoon years in KRFo93–1 were 226 t/ha/yr and 56.1 t/ha/yr in OHS, respectively and 278 t/ha/yr and 57.7 t/ha/yr in THS. Dry matter productivity was higher in THS than in OHS in KRFo93–1 but was lower in THS than in OHS in NiF8. The mechanism of high yielding ability of KRFo93-1 in THS may be caused by the vigorous initial growth after ratooning and vigorous stem elongation in the low temperature period.
