長粒型秈稻不同苗齡耐寒性反應之研究

Abstract

本研究目的為探求長粒型秈稻不同苗齡、不同溫度間耐寒性之反應，及品種之耐寒性檢定，以提供耐寒性育種親本以及耐寒性育種檢定之採用方法。 一、不同苗齡耐寒性之反應 8個品種，苗齡分為2葉、3葉、4葉、5葉、6葉等不同苗齡，採用冷水槽法，將供試品種分批播種於60×30×5cm之平盤，待秧苗長至各處理苗齡時，置放於10℃之冷水槽中，根據調查結果，品種間之反應雖不大一致，但仍顯示3葉苗齡以及5葉、6葉苗齡其反應較為敏感。 二、不同溫度與苗齡之感應 供試品種及播種方法與第一試驗相同，溫度分為6℃、8℃、10℃、12℃、14℃等5個不同處理，在幼苗長至3葉及5葉時分次置放於各處理中，結果顯示各不同溫度中苗齡之感應可分為10℃以內及12℃以上之不同感應性，即10℃以內者在級數上略高，12℃以上者約差0.5~1.0級，由此可知檢定用溫度以10℃較為適當。 三、品種耐寒性檢定 由IRRI引進122品種及本省新育成長粒型秈稻品系166個，播種於60×30×5cm平盤內，待幼苗長至3葉時置放於10℃之冷水槽內，調查其耐寒性。供試288品種（系）中，屬1級抗者只有12品種，2級者31品種（系）,3級者54品種（系），4級者最多，達138品種（系），5級者53品種（系）；在新育成長粒型166個品系中只有2個品系屬於2級抗者，由此可見今後對長粒型秈稻之耐寒性育種必須加強。 The purpose of this study was screening rice varieties as the same variety at the different seedling stage to cold tolerance, for selecting the tolerant cultivars as breeding materials and also developing a method for cold tolerance screening test. 1. Reaction at different seedling stage to cold tolerance eight varieties of 2, 3, 4, 5 and 6-leaf seedling stage of rice cultivars were tested. The seedlings were grown in 60 cm × 30 cm × 5 cm flat tray, then the seedlings were placed in the cold tank with 10°C water . Although the results revealed that the reaction among the different vaneties was not always correlated, however, it showed that at 5 and 6-leaf seedling stage was more sensitive. 2. Different seedling stage response at different temperature. The varieties tested and the sowing method were similarly as in experiment 1. The temperature was held at 6, 8, 10, 12, and 14 °C, individually. When the seedlings were at 3 and 5-leaf stage they were placed in the different temperature tank. The results showed that the response could be divided into below 10°C and above 12°C. When the temperature below 10°C, the criteria was higher, but above 12°C the criteria was lower about 0.5-1.0. Therefore, the temperature for screening was more reliable at 10 °C. 3. Screening for cold tolerance in rice varieties, 122 varieties introduced from IRRI and 116 newly developed lines of long-grain indica rice from Taiwan were sowing in 60cm × 30cm × 5cm flat tray. At the 3-leaf stage, they were placed in cold tank with 10 °C water. Among the 288 varieties (lines) tested, the reaction of criteria 1 was 12 varieties, 2 was 30 varieties(lines), 3 was 52 varieties (lines), 4 was 137 varieties (lines), and 5 was 52 varieties (lines). On the other hand, among the 116 newly developed lines of long-grain indica rice from Taiwan only 2 lines belonged to criteria 2. It is therefore, the breeding for cold tolerance of long-grain indica rice must be intensified.