Husking ratio of winnowed paddy selected by 1.06 specific gravity

Abstract

This study aimed to improve Matsushima’s yield assessment method for rice using the hills sampled along five lines parallel to a diagonal. When growing plants by transplanting young seedlings, the coefficient of variation for grain yield estimated using 30 hills selected from 238 hills was 20.8%. The number of hills to be investigated for estimating the yield with an aimed-at precision of 5% and a confidence level of 95% was 52 hills in the plot with 238 hills. The yield assessed by the above method coincided well with the actual average yield. To clarify the difference in husking ratio between the plants grown by transplanting young seedlings and mature seedlings, we analyzed the husking ratio in 312 specimens collected during 1979-2001 using a salt solution with a specific gravity of 1.06 to select ripened grains. The husking ratio was 0.824±0.009 (mean±standard deviation) and 0.844±0.005 in the plants grown by transplanting young seedlings and mature seedlings, respectively. The significant difference between the two seedlings indicated that the husking ratio of 0.840 reported by Matsushima was a characteristic value for the rice grown by transplanting mature seedlings, and that the husking ratio of 0.824 for the rice grown by transplanting young seedlings was appropriate for selecting rice because of the low variation in husking ratio.