Comparison on the Yield and the Production and Distribution of Dry Matter in Rice between Crop Seasons
|Keywords:||稻作區域性與期作性低產及增產措施之研究||Issue Date:||Dec-1984||Publisher:||台中：農業試驗所||Start page/Pages:||143-152||Source:||稻作區域性與期作性低產及增產措施之研究:||Abstract:||
一期作水稻抽穗時莖稈內江NC濃度顯著高於二期作，抽穗期營養器官內TNC含量為二期作之1.5-5.5倍，表示有較多的預貯物質。抽穗後穀粒充實期間，屏東、臺中二地區之一期作TNC生產量高於二期作。非構造性碳水化合物收穫指數(HTNCI)均高，介於0.93-0.98之間，無地區、品種或期作性差異。而產量經由預貯物質而來的百分比（Pre-heading storage contribution)，一期作介於17.8-22.5%之間，二期作為11.6-17.9%。
Two rice cultivars, Tainung 67 and Tainan 5, were grown in either Pingtung or Taichung area in the second crop of 1981 and first crop of 1982. Dry weight and contents of total nonstructural carbohydrates (TNC) and total nitrogen (N) in different plant fractions were detennined at stages of grain-filling. The purpose of this study was to investigate the causes of yield difference due to location, varietal or seasonal factors.
Dry weight per hill at heading was consistently higher for the first than for the second crop. The difference was most significant for rice grown in Pingtung area. The lower dry weight of the second crop rice was due mainly to the fewer number of tillers per hill. Results showed that on a per tiller basis, the second crop rice possessed higher dry weight. The capability of dry matter production was higher for rice of the first crop season.
Culms of the first crop rice contained 1.5-5.5 times more TNC than those of the second crop rice at heading, a result of higher TNC concentration and dry weight per hill. The production of TNC during grain-filling was supperior for the first crop rice.
Regardless of crop season or location, the harvest TNC index (HTNCI) ranged between 0.93 to 0.98. In other words, the efficiency of utilizing TNC by the rice was extremely high. The contribution of preheading storage to yield were 17.8-22.5% and 11.6-17.9% for the first and second crops, respectively.
No consistent relationship between N concentration in leaf blade at heading and final grain yield was observed. However, compared to the second crop, the first crop rice in Pingtung had lower leaf blade N but significantly higher yield, indicating the correlation between these two characters was not simple. Harvest N index (HNI) was 0.70-0.81 for the first and 0.65-0.76 for the second crop. The interaction between the translocation of N and TNC from vegetative tissue to the grain was suggested.
Analysis of yield componts showed similar 1,000-grain weight and product of spikelet number per panicle by the percentage of ripened grain. The lower yield of the second crop rice was caused by few panicle number and lower contents of dry matter and TNC at heading. The enhancement of photosynthetic capability during grain-filling was also of utmost importance in terms of increasing the yield of second rice crops in Taiwan.
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