Effects of transplanting time on the growth, yield and grain quality of the rice cultivar "Hinohikari", 1: Effects of air temperature during the ripening period on the grain quality and protein content of hulled rice
2005
Miyashita, T.(Kagawa-ken. Agricultural Experiment Station, Takamatsu(Japan)) | Mori, Y. | Murakami, Y. | Fujita, K.
The effects of air temperature during the ripening period on the grain quality and protein content of hulled "Hinohikari" rice were analyzed in a 3-year period during which the transplanting time and fertilizer application were changed. 1. "Hinohikari" is a cultivar whose hulled grain quality tends to deteriorate at high temperature during the ripening period. The inspection grade becomes poor due to high temperature, mainly when the average temperature during the ripening period exceeds 24 deg C or when the average temperature for 10 days exceeds 27 deg C from heading. 2. Grain quality becomes poor due to large numbers of unhulled grains per unit area when the average temperature during the ripening period is 23-24 deg C. Within this thermal range the number of unhulled grains must be limited to 28,000 or less per square meter to maintain the grain inspection grade. 3. The protein content changes according to temperature during the ripening period in addition to the quantity of nitrogen supplied, and becomes low when the average daily minimum temperature falls below 17 deg C, or when the average temperature falls below 22 deg C, during the ripening period. 4. The optimal heading time for best grain quality and flavor in the flat area of Kagawa Pref. estimated by climatic productivity was from August 30 to September 3.
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