Studies on the Characters of the Improved Semi-Dwarf, High-Yielding Indica Rice Varieties : II. Shape and quality of rice kernel, especially occurrence of white belly kernel

[摘要] We conducted this work to get the informations about the shape and quality of rice kernel in the improved indica varieties, comparing with the japonica varieties. The results obtained are as follows: 1. In all varieties, a high positive correlation (r=0.9065) was found between the hull weight and the length × width of the kernel. 2. In all varieties, there was no correlation between the hull weight and the thickness of the kernel, but the varieties, which had bigger hulls, had a greater thickness in the kernel in the japonica varieties. On the other hand, the varieties which had bigger hulls and whose kernel's length × width were over 16 mm2, had a smaller thickness in the kernel in the improved indica varieties. 3. Varietal differences of the increase in the grain weight were observed. Among the early varieties, the increase in the grain weight stopped more rapidly in Chosaeng Tongil which belongs to the improved indica variety than in Gohyakumangoku and Reimei which belong to the japonica variety. 4. White belly kernels occured more in the very early varieties and the improved indica varieties except SML 680 2/1 which is long slender kernel. At the heading stage, they had a much smaller leaf area per spikelet than the other japonica varieties. 5. In the japonica varieties, Gohyakumangoku Llnd Jinheung had a much bigger hull than the other japonica varieties (almost the same with IR-8, Chosaeng Tongil, SML 680 2/1, Namking 11, which belong to the improved indica variety.) and their grain weight were much larger than the improved indica varieties. But the percentage of the occurrence of white belly kernel was much lower in these than in the improved indica varieties. At the heading stage, they had 1.2 to 2.2 times larger leaf area per spikelet than the improved indica varieties. 6. A long slender kernel variety SML 680 2/1 produced 18.8% of white belly kernel, though the percentage was much smaller than that of the other indica varieties. 7. The opaque part of the white belly kernel was small in the very early varieties which had a small hull, and very large in the improved indica varieties which had a large hull.

[学科分类] 农业科学（综合）