Study on wintering-resistant ability of raspberry

Abstract：In order to expolre the death reasons of raspberry cultivars during overwintering in open field in Shenyang area,the changes of electrical conductivity,sprouting rate and water content of cane were mea- sured and the dynamic change of stem skin was also observed in four raspberry cuhivars （Rubus idaeus L.）, Royalty, Autumn Bliss, Heritage and Victory, and a wild raspberry species R. crataegifolius Bge. The re- sults showed that the wild one could survive very well in open field in Shenyang area, but all of the four cuhivars were dead after overwinter. The main reason for death was low temperature and low humidity. The quick decrease in air humidity with the increase in temperature in early spring after continuous low tem- perature in winter resulted in abundant water loss of cane. The critical period was from February 8 to March 8 in Shenyang area. The winter-resistant ability ranked R. crataegifolius〉Heritage〉Autumn Bliss〉 Royalty〉 Victory.