利用恆溫箱檢定稻苗耐寒性之研究－Ⅱ.低溫與處理時間對稻苗成活率之影響

Abstract

以嘉農秈11號、新竹矮腳尖、IR22、臺農61號，臺中65號、山胄、永川沙刁子及B-J1之2~3葉齡之秧苗，利用恆溫箱(Incubator)，經分別以8℃、5℃及3℃低溫處理1、2、4及6天後，發現苗期的耐寒性，品種間有極大差異。稻苗成活率(Rato of survival)依溫度下降程度及處理時間之延伸而隨之降低，但各品種間顯示不同下降幅度，耐寒性強品種，下降幅度較小，反之較大。同時，品種間依其對低溫之反應，可明顯的區分出抗性品種或敏感品種，前者如臺中65號、臺農61號、山冑及永川沙刁子，具有較強的耐寒性(Cold tolerance)品種形成一羣；後者如IR22、BJ1等品種對低溫呈敏感反應者，形成另一羣（圖9-11）。 間歇性低溫與連續性低溫，經以相等時問處理結果，顯示二者對稻苗成活車之反應相似，8個品種中仍以臺中65號、山冑等品種，耐寒性較強，IR22、BJ1耐寒性最差。 The rice seedlings at 2~3 leaves stage from eight rice varieties were involved in the chilling tolerance experiment. There were three levels of chilling temperature, namely 3°C, 5°C and 8°C and four levels of duration, such as one, two, four and six days. All the experimental work was conducted in an incubator. Significant difference were found among the varieties in chilling tolerance tested. Rate of survival decreases as the temperature declines and duration elongate. However, different degrees of chilling tolerance were found among varieties. Those which resisted chilling temperature had higher rate of survival than those susceptable ones, and it can be classified clearly into resistant and susceptable groups, by judging the responses of varieties to chilling temperatures. The some result was also obtained from another experiment by treating rice seedlings alternately in an incubator (5°C) and net house (air temperature). From the results, it may be concluded that the chilling tolerance of rice variety may be identified by testing rice seedlings in an incubator at 5°C for 48 hours.