An indica rice cultivar, Milyang23 is a semidwarf plant type with long and slender grains, whereas a temperate japonica rice cultivar, Stejaree45 is a japonica cultivar with short and bold grains. Genetic analysis was carried out to determine the number of quantitative trait loci (QTL), chromosome location, gene action, and effects of QTLS controlling grain length, width, thickness, and shape. The grain traits averages in the recombinant inbred lines (RILs) were near the mid-parent value, but the standard deviations in the RILs were more than those of the parents. A linkage map based on 138 simple sequence repeat (SSR) markers from 12 linkage groups was constructed using the 143 RILs as the base population. The map, spanning 1208 cM of the rice genome with an average interval length of 12.9 cM, was used for QTL analysis. A total of 13 QTLS for grain quality traits were identified. The phenotypic variation accounted for by each QTL ranged from 4.2% to 10.4%, with an average of 6.7%. Among the 13 QTLS, only one QTL accounted for more than 10% of the total phenotypic variation. Each of the traits studied was governed by one or two major QTLs that accounted for the large proportion of the total phenotypic variation. Several minor QTLS explain a small proportion of the total phenotypic variance.

1. 도복정고에 따른 주요 작물학적 특성은 도복시기가 빠르고, 도복정도가 심할수록 수당립수는 많았고, 등숙비율은 낮았으며, 현미천립중은 가벼웠다. 2. 완전미도정수율은 출수후 20일 완전도복(9), 출수후 20일 반도복(5), 출수후 25일 완전도복(9), 출수후 25일 반도복(5), 출수후 30일 완전도복(9), 출수후 30일의 반도복(5), 무도복 순으로 높게 유의성이 인정되었다. 따라서 도복에 따른 완전미도정수율은 도복시기가 빠르고 도복정도가 심할수록 낮아지고 분상질미, 쇄미 및 사미는 증가하는 경향이었다. 3. 밥의 찰기와 질감에 나쁜 영향을 주는 단백질함량이나 밥맛을 간접적으로 비교하는 토요식미치와 실제적인 페널에 의한 밥맛은 무도복에 비해 도복시기가 빠르고 도복정도가 심할수록 식미가 나빠지는 쪽으로 영향을 미쳤고, 도복 시기보다는 도복정도가 더 많은 영향을 미치는 것으로 판단된다.