抄録
In the previous papers, it was suggested that the producing district of rice in Hokkaido had an effect upon the protein content of lowland brown rice. In order to confirm the effect of producing district on the chemical composition of lowland brown rice in Hokkaido, 120 samples of Norin No. 20 from 4 municipalities, 300 samples of Shiokari from 11 municipalities and 150 samples of Sorachi from 6 municipalities were collected in 1972 and investigated for the protein content (experiment 1) and 60 samples of Shiokari from 4 municipalities were further collected in 1973 and investigated for the protein, fat, ash, phosphorus, potassium, magnesium, manganese and iron content (experiment 2). The producing district had a significant effect upon the protein content of each variety in experiment 1 and 2. With respect to the average values of each variety at the producing districts, the highest was about 20% more than the lowest. As a factor of the variance of the protein content, it was presumed that the paddy field of peat soil brought about the high value because of liberating nitrogen by decomposition of the soil at the late growing period. In experiment 2, the producing district had a significant effect also upon thc chemical components except iron. The high protein district, as compared with the low protein district, was higher in ash content and phosphorus and magnesium content on dry matter basis and was lower in manganese content on dry matter basis and potassium and manganese content in ash.
