Abstract:

In order to improve the grafting survival rate of hybrid offspring in the breeding process of new citrus varieties, and improve the breeding efficiency, the effects of hot water soaking at different temperature and time on the germination and growth of citrus seeds were studied by using single and multiple embryo seeds of citrus as test materials. The results showed that in the range of water temperature of 50-55 ℃, with the increase of temperature, radicle length, radicle growth, stem length and germination rate of single and multiple embryo seeds, showed a trend of first increasing and then decreasing, and reached the highest at 52 ℃, which were 16.02 mm, 20.79 mm, 27.59 mm, 81.36% of single embryo seed and 10.56 mm, 29.61 mm, 42.10 mm and 90.00% of mutiple embryo seed, respectively. From the morphological observation, it can be seen that soaking seeds in hot water at 52 ℃ had a high seed germination rate, fast growth of radicle, and good uniformity. In the time range of 10-30 min soaking in hot water at 52 ℃, with the increase of soaking time, radicle length, radicle growth, stem length and germination rate of citrus seeds increased first and then decreased, reaching the highest at 20 min, which were 12.95 mm, 31.54 mm, 37.89 mm and 81.40%, respectively. In conclusion, the hot water soaking treatment of citrus seeds at 52 ℃ for 20 min can improve the germination uniformity and grafting survival rate of citrus seeds, which is suitable for citrus single and multiple embryo seeds. This study provides a technical reference for the breeding of new citrus varieties, ploidy breeding and citrus seed germination treatment in production.

Key words: hot water soaking, citrus, germination, grafting