Reduction of Grain Yield in Rice Shaded during the Early Grain Filling Period is not the Result of Inhibition of Potential Grain Dry-Matter Increase

Japanese Journal of Crop Science

Makoto SUGAWARA¹  Tohru KOBATA¹ 

关键词: Grain;    イネ;    Potentiality of grain dry matter increase;    茎葉貯蔵産物;    Reserved assimilate;    子実;    Rice;    遮光;    Shading;    潜在的子実乾物増加量;   

DOI  :  10.1626/jcs.69.413

学科分类：农业科学（综合）

来源: Nihon Sakumotsu Gakkai / Crop Science Society of Japan

【 摘 要 】

A shortage of carbon assimilate supply to rice grain during the first ten days after heading(DAY0-10)has been considered to reduce the potential grain dry-matter increase(ΔGP). It was, however, uncertain whether assimilate supply after the shading period was sufficient to support ΔGP when the reduction of grain dry-matter increase(ΔG)was observed. Our objective was to demonstrate that ΔG after the shading treatments was reduced not through the decrease in ΔGP but through a lack of assimilate supply, based on our model analysis. In our model, ΔG is determined by assimilate supply(current dry-matter production(ΔW)plus reserved assimilate in straw(SP)and the ΔG has an upper limitation defined by ΔGP. In this study ΔGP was estimated under a sufficient supply of assimilates which were provided by periodical thinning of the plants. By the shading during DAY0-10, ΔG as well as ΔW were reduced even after the end of the shading treament. Observed ΔW and SP at the heading were input to the model to calculate ΔG and straw dry-matter increase(ΔS). The calculated dry weight of the grain and straw coincided closely with the actual observed data. We herewith suggest that the grain dry-matter increase by shading during DAY0-10 was not suppressed by inevitable reduction of ΔGP but rather by a lack of assimilate supply during the active ΔG period.

【 授权许可】

Unknown