穀粒充實期間氣象因子對「台稉9號」產量與米質狀之影響

本研究於2008-2012年在行政院農委會農業試驗所農場（台中市霧峰區）進行5年期間上、下半年稻作之節氣栽植，每年以立春／大暑為中心前後各推延2個節氣之10水稻栽植期，5年總計49個栽植期。本研究試材為「台稉9號」（‘TK9’），試驗期間收集試區鄰近一級農業氣象測站氣象測值之日均溫（DMAT）、日最高溫（DMAXAT）、日最低溫（DMINAT）、日照時數（DSH）及日射量（DIR）等5項氣象因子，計算穀粒充實期間之測值累加值（即ADMAT、ADMAXAT、ADMINAT、ADSH、ADIR）其等平均值（即MDMAT、MDMAXAT、MDMINAT、MDSH、MDIR），合計49個栽植期之各49組參數值，據以分析氣象變數對「台稉9號」產量與米質性狀之效應。經由相關分析結果顯示，上半年的白米粗蛋白質含量及白度與ADMAT、ADMAXAT及ADMINAT呈極顯著正相關，而直鏈性澱粉和透明度則與此3項溫度變數呈極顯著負相關。進一步利用複回歸分析之逐步選擇法，亦顯示穀粒充實期間累加溫度變數乃為影響米質性狀表現之重要氣象因子，惟其影響權重會因為上、下半年栽植期的氣象環境不同而有所差異。又由複回歸分析顯示，產量與3項平均溫度變數（MDMAT、MDMAXAT及MDMINAT）皆分別呈現凸二次曲線關係，上半年栽植期於穀粒充實期階段之MDMINAT近於22.5℃、MDMAT近於26℃、MDMAXAT近於31℃時，而下半年則分別為MDMINAT近於20℃、MDMAT近於24℃、MDMAXAT近於29℃時，可獲得最大穀粒產量。又由米質性狀與3項平均溫度變數之複回歸分析，發現白米的粗蛋白質和白度與平均溫度之間具有凹二次曲線關係，而直鏈性澱粉和透明度則與平均溫度之間呈凸二次曲線關係，其中以上半年的變化幅度較為顯著。綜合試驗結果，可知溫度變數為影響「台稉9號」產量及米質性狀之重要氣象因子，從該品種主要栽植地區（如苗栗、台中、彰化及雲林）之氣溫歷史資料及上述試驗結果分析，發現上半年的一期稻作穀粒充實期間最適月份落在5月份，而二期稻作則落在10月份。進一步推算這些地區栽植適期，則上半年的一期作栽植適期為立春前15 d，下半年的二期作則為大暑後15 d。

關鍵字

節氣；立春；大暑；日均溫；日最高溫；日最低溫

並列摘要

A five-year field study was conducted in the experimental farm of Taiwan Agricultural Research Institute (TARI) (Wufeng District, Taichung City) in 2008–2012. Rice (＂Oryza sativa＂ L. cv. 'TK9') plants were planted in 'Lichun' (means 'start of spring') in the first half and 'Dashu' (means 'major hear') in the second half of the year as well as one and two solar terms before and after them in each year. There were 49 planting times/seasons in total within five-year experimental period, where weather data were also collected from the nearby weather station located at TARI. Five climatic factors, namely, daily mean air temperature (DMAT), daily maximum air temperature (DMAXAT), daily minimum air temperature (DMINAT), daily sunshine hours (DSH), and daily irradiance (DIR) were computed to calculate the respective cumulative (i.e., ADMAT, ADMAXAT, ADMINAT, ADSH, and ADIR) and average (i.e., MDMAT, MDMAXAT, MDMINAT, MDSH, and MDIR) values of these variables during grain-filling stage (from anthesis to harvest). The effects of climatic factors on yield and quality of this cultivar were analyzed based on these datasets. From the results of correlation matrices, crude protein and whiteness of milled rice were positively correlated, while amylose and transparency were negatively correlated, with ADMAT, ADMAXAT and ADMINAT in the first half year. By the stepwise selection of multiple regression analysis, results indicated that the cumulative values of temperatures were the main climatic variables affecting rice quality, but their weights varied with changes in climatic environment in both the first and the second halves of the year. Results showed that rice yield was closely correlated with MDMAT, MDMAXAT, and MDMINAT in a convex curvilinear function. In the first half, the maximum values of yield for MDMINAT, MDMAT and MDMAXAT were occurred near 22.5, 26, and 31℃, respectively, but were shifted to 20, 24, and 29℃ in the second half. Rice quality was also significantly correlated with these three variables in a curvilinear fashion. Crude protein and whiteness of milled rice were positively correlated while amylose and transparency were negatively correlated. Variation was in a greater extent in the first half of the year. As a summary, temperature variables are more important in determining grain yield and rice quality of cultivar 'TK9'. When combining the experimental results with historical weather data of the major production areas (Maoli County, Taichung City, Changhua County, and Yunlin County) of this cultivar, the best month for grain filling is May in the first half and is October in the second half. To better match these two months for these areas, the first crop should be planted at 15 days before 'Lichun' while the second crop should be cultivated at 15 days after 'Dashu'.

並列關鍵字

Solar term ； Lichun (start of spring) ； Dashu (major heat) ； Daily mean air temperature ； Daily maximum air temperature ； Daily minimum air temperature

國際替代計量

穀粒充實期間氣象因子對「台稉9號」產量與米質狀之影響

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