胡麻の品種に關する研究 : (5)胡麻の發芽温度ならびにこれが2〜3の形質との關係について

抄録

Using 39 typical varieties of sesame collected in seven countries including Japan as material, experiments were carried on the relation between germination temperature and varietal difference, and the correlation between germination, seed weight and percentage of oil content. In germination experiments for which a Jacobsen germinater was employed, 12 stairs at intervals of 5 degrees with 5℃ as the lowest and 60℃ as the highest temperature was contrived to grade germination temperature; and the germination rate and the germination ratio were 3 and 10 days respectively. The materials employed in the experiments were obtained from the 1957 crop and the experiments carried on at the Shikoku Agricultural Experiment Station in the same year. The results of the experiments are : (1) There was no germination of any variety at either 5℃ or 60℃. It was found that the germination temperature of sesame ranges from 10℃ to 55℃, the proper temperature being between 30℃ and 35℃. (2) The germination temperature of all varieties collected in Israel was 15℃ at the lowest and 50℃ at the highest ; of all the varieties employed for the experiments the Israeli varieties had the narrowest range of germination temperature and the lowest germination coefficient. (3) On the whole, American, Japanese and Chinese varieties had a wide range of germination temperature, and their germination was satisfactory at both low and high temperatures. (4) It was found that, generally, the varieties growing in tropical regions show poor germination at low temperature and good germination at high temperature, while those cultivated in northern regions not only retain the quality of germinating well at high temperature but also germinate fairly well even at low temperature. (5) The covariance of seed weight and the germination coefficient at 15℃ showed that in the case of the Japanese varieties all the light-seed varieties had high germination coefficient, while in the case of the American varieties some of the light-seed varieties had high, and the others, low germination coefficient. In the case of 45℃, the Japanese varieties had (-) correlation as in the case of 15℃; the African varieties had 1 per cent significant of (+), and the Indian varieties almost 5 per cent significant of (+), correlation ; the American varieties, as in the case of 15℃, had high-germination coefficient ones and low-germination coefficient ones mixed in them. (6) The covariance of percentage of oil content and the germination coefficient at 15℃ showed that, on the whole, the higher the percentage of oil content was, the higher the germination coefficient; especially the American varieties had much of this tendency. There were some exceptional varieties, however, such as the Indian varieties, whose germination coefficient was extremely low in spite of their high percentage of oil content. In the case of 45℃, the general situation was much the same as in the case of 15℃, except for the Indian varieties which had nearly 5 per cent significant of (-) correlation. (7) It seemed that there was a fairly close correlation between germination temperature and light sensitivity. Those varieties of low light sensitivity to both short-day and long-day, or those of low short-day sensitivity and high long-day sensitivity had, on the whole, a wide range of germination temperature. It was also found that those of high light sensitivity to short-day and long-day showed poor germination at low temperature and good germination at high temperature.