Abstract
The effect of harvest time on the quality and protein content of paddy rice cultivated by using an Aigamo duck (crossbreed of wild and domestic ducks) farming system was examined. Prefect rice grain was increased with the delay of cultivation was 7.3+0.1%, and that of Koshibikari in the 5th year of Aigamo cultivation (the 7th year of organic cultivation) was 7.8+0.4%. The protein content of Koshihikari under Aigamo cultivation was deceased 0.7% at most by a 10-day delay of the harvest time from the mature stage. Yield components were influenced by the harvest time only slightly, and the yield was slightly increased by delaying the harvest time. The rate of grren-kerneled rice was closely correlated with the protein content, and the protein content decreased with decreasing rate of green-kerneled rice. In the evaluation by sensory test for palatability, the best was early harvest, followed by late harvest and maturity harvest, in this order. This tendency was notable particularly in the rice in the 5th year of Aigamo cultivation (the 7th year of organic cultivation). These results suggest that 10-day delay of the harvest time from the usual time decreases the rate of green-kerneled rice, increases the crop yield, and improves palatability by decreasing the protein content in the brown rice.
