Effect of harvest time on IR44 ratoon grain yield.

Abstract

The effect of time of harvest of an IR44 rice ratoon crop on grain yield was studied between Dec. 1983 and July 1984. The ratoon crop was harvested at 75, 80, 85 and 90 days after main crop harvest. Main crop grain yield was 516 g/m. Ratoon crop harvest time significantly affected spikelet fertility, number of filled grains and ratoon grain yield. Ratoon grain yield varied from 126 g/m for 75 days after main crop harvest (DAH) to 168 g for 85 DAH. Lowest grain yield (136 g) was at 75 DAH and the highest was at 85 DAH. Differences in grain yield were not fully explained by differences in spikelet fertility. Opt. time for harvest of ratoon crop was 80-85 days after main crop.