氣象變因對臺灣不同地區選育稻種產量性狀之差別效應

Abstract

氣象變因對稻作產量之影響，可針對產量性狀之分析獲得全貌，而透過對不同地區選育稻種產量性狀之剖析，則可歸納出氣象環境之區域性差別效應。本研究於2010－2012年在行政院農業委員會農業試驗所農場（臺中市霧峰區）進行三年期間上、下半年稻作之‘節氣’栽植，分別以立春（SS）及大暑（MH）為中心節氣前後各推延2個節氣，每年計有10次栽植期，三年總計30個栽植期。本研究試材為‘臺稉9號’（'TK9'）、‘臺南11號’（'TN11'）、‘臺稉16號’（'TK16'）及‘臺東30號’('TT30')等4個良質稻種，試驗期間收集試區鄰近一級農業氣象測站之氣象測值，計算各稻種各栽植期之不同生育階段各氣象變因累加值及平均值。例如，穀粒充實期間計算之氣象變因平均值有平均日最低溫（MDMINAT）、平均日均溫（MDMAT）、平均日最高溫（MDMAXAT）、平均日照時數（MDSH）及平均日射量（MDIR）等5種。綜合3年期間4個稻種產量資料，發現上、上半年節氣栽植期之產量均參差不齊，而以下半年之MH及MH+15兩節氣栽植期在全部稻種皆獲得相對較高產量，且以稔實率（PFG）在產量性狀中具有較高互動。續由多元線性複回歸之逐步選擇法分析氣象變因與產量性狀關係，以上半年3項溫度變因在PFG及千粒種（1000-grain weight）表現上相對具有較高權重。經匯合4個稻種3年資料，歸納出上半年栽植期之抽穗前後期間可得到最大稔實率的最佳MDMINAT為22.3℃、MDMAT為25.3℃、MDMAXAT為29.8℃，下半年栽植期則僅MDMAXAT與4個稻種稔實率之回歸曲線關係達顯著水準。又由匯合產量與溫度變因間二次凸形曲線關係，歸納出上半年栽植期之穀粒充實期間可得到最大產量的最佳MDMINAT為22.3℃、MDMAT為26.0℃、MDMAXAT為31.0℃，下半年栽植期則分別MDMINAT為20.5℃、MDMAT為24.0℃、MDMAXAT為29.8℃。綜合試驗結果，顯見在霧峰地區以溫度變因為影響4個稻種產量之主要氣象變因（具高權重），而藉由本研究多元線性複回歸與二次曲線趨勢圖的結果，可比較品種間產量之差別效應，且可進一步提供未來研擬全球暖化情境下水稻栽培環境之管理策略。 By the analysis of their individual influences on each yield components, it provides a basis for further profiling effects of climatic variables on rice yield. With a disintegration of yield components of rice cultivars bred from varied regions, differential regional effects of climatic environment are reasonably clarified and explained. Field experiments were conducted at Taiwan Agricultural Research Institute Experimental Farm (Wufeng, Taichung) in 2010-2012 with a total of 30 cropping seasons, based on a planting schedule by 24 Solar Terms calendar. Four cultivars of rice (Oryza sativa L.), 'TK9', 'TN11', 'TK16' and 'TT30', bred from different regions in Taiwan were selected, and weather data recorded from nearby meteorological station were used. The average values of daily minimum air temperature, daily mean air temperature, daily maximum air temperature, daily sunshine hours and daily irradiance in different growth stages were calculated as climatic variables. For example, five variables calculated from grain-filling stage were denoted as MDMINAT (the average value of daily minimum air temperature), MDMAT (the average value of daily mean air temperature), MDMAXAT (the average value of daily maximum air temperature, MDSH (the average value of daily sunshine hours) and MDIR (the average value of daily irradiance), respectively. Results of the analyses on the pooled data of 4 cultivars in three years showed that rice planted at solar terms MH and MH+15 had a relatively higher yield production in the second-half years, and percent filled grain (PFG) was the yield component most followed it. By the step-wise selection of multivariate regression analysis, temperature variables were found to impose greater weights on yield components PFG and 1000-grain weight for rice planted in the first-half years. Results also indicated that in the first-half years, the highest PFG was acquired when MDMINAT, MDMAT and MDMAXAT were near 22.3, 25.3 and 29.8℃, respectively, during the grain-filling stage. Based on convex curve relationships between yield and temperature variables, optimal values of MDMINAT, MDMAT and MDMAXAT to obtain the maximum grain yields were near 22.3, 26.0 and 31.0 ℃ , respectively, during the grain-filling stage in the first-half years, while these values changed to 20.5, 24.0 and 29.8 ℃ in the second-half years. Accordingly, temperature variables were the major factors determining yield of these rice cultivars in the trial site as well as imposing differential effects on respective rice cultivars. Such information is the needed input to draw up management strategies for growing rice under the scenario of global warming trend.