Characteristics of Dry Matter Production Process in High Yielding Rice Varieties : I. Canopy structure and light intercepting characteristics

Japanese Journal of Crop Science

Hiroyuki SHIMODA¹  Kuni ISHIHARA¹  Kuniyuki SAITOH¹ 

关键词: Dry matter production;    イネ;    Growth analysis;    乾物生産;    High yieldintg variety;    吸光係数;    Light extinction coefficient;    受光態勢;    Light intercepting characteristics;    生長解析;    Rice plant;    多収性品種;   

DOI  :  10.1626/jcs.59.130

学科分类：农业科学（综合）

来源: Nihon Sakumotsu Gakkai / Crop Science Society of Japan

【 摘 要 】

In order to clarify the eco-physiological characteristics of high yielding rice vaieties, yields, their components and the process of dry matter production were compared between the cultivar Milyang 23, Japonica × Indica hybrid high yielding variety, and the cultivar Nipponbare, a japanese standard variety, for five years from 1983 to 1987. The maximum yield of Milyang 23 in 1984 was 754 g/m2, 32% higher than that of Nipponbare owing to higher dry matter production and more spikelets number per unit area. The process of dry matter production was examined by growth analysis method. Crop growth rates of Milyang 23 were higher after heading stage, especially at the early ripening stage, as compared with those of Nipponbare. It was not owing to larger mean leaf area index, but owing to higher net assimilation rate. Light extinction coefficient was lower in Milyang 23 at the early ripening stage owing to more erect foliage and smaller mutual shading effect of ears on the leaf canopy as compared with that of Nipponbare. To verify a role of smaller light extinction coefficient for increase in dry matter production in Milyang 23, thinning treatment (the planting density was reduced to half of the control) was done at three growth stages. Net assimilation rates increased by thinning treatment. The degree of increase in net assimilation rates by thinning treatment differed in the two varieties; that is, larger in Nipponbare with larger light extinction coefficient than that of Milyang 23 with smaller coefficient, especially at early ripening stage. These results indicate that the difference in net assimilation rates between the two varieties was mainly due to the difference in light intercepting characteristics. In order to clarify the difference of net assimilation rate between both varieties, further studies must be made on the characteristics relating to leaf photosynthesis which is thought to be one of the factors to maintain higher net assimilation rate in rice canopy.

【 授权许可】

Unknown