利用恆溫箱檢定稻苗耐寒性之研究(I)水稻類型及苗齡大小對低溫忍受力之差異

Abstract

採用兩個稉稻及四個秈稻品種為供試材料。為培育不同苗齡之稻苗，各供試稻種每隔二天播種一次，共播14次。此等不同苗齡稻苗，係利用恆溫箱（Incubator）控制溫度，同時進行3℃，2天的低溫處理，以探討水稻不同苗齡及稻種類型間耐寒力之差異，俾供試驗場所實際從事水稻抗寒育種或有關試驗之參考。試驗結果摘要如下： 1. 水稻不同類型或品種間之不同苗齡，對低溫（3℃處理2天）的反應，發現稻苗在萌芽或幼苗期間之耐寒力很強，以後隨苗齡之增大，對低溫愈敏感，其受害亦愈大。 2. 稻苗發育至3葉齡，即第二完全葉完全張開的稻苗，以3℃低溫處理2天，最易辨別不同類型或品種間抗寒力之強弱。 3. 稉稻之耐寒力較秈稻為強。供試品種中以新竹朮四號（稉稻）的耐寒性較強；秈稻則以新竹矮腳尖耐寒力最強。 Two japonica and four indica type varieties of rice, were used to study the response of rice seedlings of various ages for tolerance against chilling temperature. Fourteen batches of seedlings raised at 2 days intervals were treated at 3°C for 2 days in an incubator. The results obtained were summarized as follows: 1. The younger the seedling age, the more tolerant to chilling injury, and severe injury was observed in the older seedlings. 2. The rice seedlings of 3-leaf ages were found to be most suitable to distinguish the varietal difference in cold resistance, because the difference in survival rate between tolerant and susceptible varieties was the largest at this stage. 3. In general, japonica varieties showed higher survival rate, indicating that they tolerate more to the low temperature than that of indica varieties. Hsinchu glutinous 4 was found to tolerate more than Taichung 65 within Japonica varieties, while, Hsinchu-Ai-Chueh-Chien toleranted the most to the low temperature within the Indica varieties tested.