Abstract
Occurence of varietal differenccs in the protein content ot. brown rice were investigated with reference to some agronomic traits. The results obtained are as follows; 1. At the heading stage, LAI was smaller in earlier heading varieties than in later ones, but there was no difference in the numlber of spikelets per m2 according to varieties' maturity. Accordingly the leaf area per spikelet was smaller in earlier heading varieties. So dry matter production per spikelet was less in these varieties. On account of this, ripening percentage became lower and the weight of kernel bccame lighter in earlier heading varieties. 2. On the other hand, at the heading stage, the nitrogen content of the plant body was higher in earlier heading varieties, but there was no difference in the nitrogenquantity of the plant body per spikelet according to the varieties' maturity. And the degression of nitrogen content of leaf blade during ripening period was greater in earlier heading varieties. 3. From these results, nitrogen accumulated in kernel relativey more than starch in these varieties, so that protein content became higher in these varieties. 4. Protein content increased by shading treatment during ripening period and the degree of increasing was higher in earlier heading varieties.
