Abstract: Rice breeding for ideal plant morphology is in effect the breeding for high light utilization. Thus, its theoretical basis is inevitably to both the genetic and physiological aspects of knowledge. The varietal difference in specific leaf weight and chlorophyll content, which are regarded as the essential elements of leaf quality, is quite significant, especially the former seems to be more stable than the latter and more consistent under different conditions. Besides, there is significant positive correlation between specific leaf weight and chlorophyll content, each of them is positively correlated with leaf nitrogen content to be highly significant, and the latter in turn is positively correlated with net photosynthetic rate to be highly significant too. Leaf area, specific leaf weight and chlorophyll content are highly related to well-filled grains per panicle and to the average panicle weight, with the order leaf area > specific leaf weight > chlorophyll content in the degree of relationship. Among these, the direct effect of specific leaf weight in relation to panicle weight is comparatively more marked, and that of chlorophyll content may become more and more important with respect to dry matter production in the later stage of growth. Therefore, in rice breeding for ideal plant morphology, in particular for maximal sunlight utilization, while leaf area is to be firstly considered, attention should also be paid to specific leaf weight and chlorophyll content. Since estimation of leaf area, specific leaf weight and chlorophyll content is rather easy to handle, which can be done either by eye (for leaf area and chlorophyll content) or by hand touching, this method is of practical importance in screening so large progeny as in rice breeding.

Key words: rice breeding, ideal plant morphology, specific leaf weight, chlorophyll content, yield component

摘要： 水稻理想株形育种确是高光效育种，因而应以遗传及生理两方面的知识作为理论基础。反映叶片质量的比叶重和叶绿素含量，品种间差异很大，但前者又比后者受环境的影响较小。除比叶重和叶绿素含量之间有明显的正的关系外，两者都与叶片含氮量有极显著正相关，后者又与净同化率有极显著的正相关。叶面积、比叶重和叶绿素含量与每穗成粒数、平均穗重都有极显著的正相关，其大小顺序为叶面积＞比叶重＞叶绿素含量。在后二者中，比叶重对穗重的直接贡献较大，叶绿素含量对干物重的作用则越到后期越明显。因此水稻理想株形的高光效育种在重视叶面积的同时，还应注意比叶重和叶绿素含量。上述叶片三个性状的测定方法都比测含氮量简便，且都可用目测（叶面积和叶绿素含量）或手感（比叶重高者其叶厚挺），这对田间筛选大量材料具有实用意义。

关键词: 水稻育种, 理想株型, 比叶重, 叶绿素含量