Abstract: In the first ten days of April 2020, a long-term low temperature weather process occurred in western Guizhou, which led to a large number of flower and fruit drop of red cartridge kiwifruit which was in the period of flowering and fruit setting. In view of this to ascertain the effects of low temperature on fruit setting of red cartridge kiwifruit in early April 2020, we investigated the fruit setting rate of red cartridge kiwifruit in nineteen main planting areas of Western Guizhou from April 10th to 17th. And, combined with the data of the daily average temperature and minimum temperature from April 3th to 9th, the study analyzed the effects of cold weather on flowering and fruit setting of red cartridge kiwifruit in western Guizhou. In order to provide scientific basis for prevention and mitigation of low temperature disaster and take reasonable countermeasures, the low temperature conditions affecting the flower and fruit drop of red cartridge kiwifruit in Guizhou Province were found out. The results showed that the cold weather from April 3th to 8th caused serious flower and fruit drop of red cartridge kiwifruit during their flowering, pollination, fertilization and fruit setting stage. The highest rate of flower and fruit drop was 70% in Shunchang, Xinyao and Pugu, and the second is 64.5% in Shaomi, and the third is 63.3% in Houchang. The lowest rate of flower and fruit drop was 10% in Mugang, and the second is 29.5% in Dayong. Through analysing the first-flowering dates and the time of flowering and pollination, it was found that the earlier first-flowering dates, the longer time of flowering and pollination, the rate of flower and fruit drop was higher. Besides, it was found that the rate of flower and fruit drop of Hongyang varieties was higher than that of Donghong varieties. In the period of flowering, pollination, fertilization and fruit setting stage of red cartridge kiwifruit, it was found that when the daily average temperature＜12℃ and the daily minimum temperature＜10℃ last 3 days or more, or when the daily average temperature＜15℃ and the daily minimum temperature＜13℃ last 5 days or more, it would cause flower and fruit to fall. In production, spraying antifreeze, smoking and other measures can prevent low-temperature freezing injury, and reduce the impact of low-temperature weather on the flowering, pollination and fruit setting of red cartridge kiwifruit trees.

Key words: Red cartridge kiwifruit, Flowering stage, Pollination stage, Cold weather, Time of duration, Flower and fruit drop