(30(3):201-214)Influence of climate on the yield and agronomic characters of the first and second crop rices in Taiwan

利用全省7個地區，5個品種之22套水稻長期區域試驗資料來分析氣象因子對農藝性狀之影響。所考慮之氣象因子有抽穗前45天及抽穗後30天之平均氣溫及平均日照時數，農藝性狀有生長日數（由移植到抽穗日數）、成熟日數（由抽穗到成熟日數）、株高、穗數及產量等。因子分析的結果發現氣象因子影響農藝性狀的方式及程度因地區、品種和期作而互異，期作間之差異與氣象因子的關係亦隨地區、品種而有所不同。此種現象不僅是由於品種本身遺傳的機制對氣象變化反應的不同，亦由於存在有遺傳與環境的交感年用。正典相關分析的結果顯示4氣象因子與5個農藝性狀的相關性以臺中及屏東地區為最大，對品種而言則臺南5號之相關性最高。本研究認為一、二期作產量提高的關鍵在於如何由育種上及栽培上去盡量利用氣溫及日照這二大天然資源。A total of 22 sets of data including 7 regions and 5 varieties from long-term regional trials were used to study the influence of climatic factors on the agronomic characters of rice. Climatic factors considered were the mean air temperature and the mean sunshine hours 45 days before and 30 days after heading respectively. Agronomic characters studied were the days of growing (days from transplanting to heading), days of maturing (days from heading to maturing), plant height, number of panicles and the yield. Results from factor analysis revealed that the pattern and the magnitude of the climatic influence on the agronomic characters (1st crop, 2nd crop or inter-crop difference) differ quite a lot from region to region and from variety to variety. The different response to climatic change due to the genetic mechanism of the varieties themselves is not the only cause attributed to thus phenomenon, there are also evidences indicating the existence of the genetic-environment interaction. Results from canonical correlation analysis showed that Taichung and Pintong have the highest association between the 4 climatic factors and 5 agronomic characters. As for the variety, Tainan 5 is the most prominent one. Utilization of temperature and solar radiation to improve the rice yield is suggested and briefly discussed