Comparison of cold resistance in 80 Punica granatum using relative elec⁃ trical conductivity method and Logistic equation

Abstract:【Objective】Pomegranate has a long cultivation history and is extensive distribution in China. Itis an important economic fruit tree, but freeze injury seriously restricts the development of pomegranate industry. Taking annual dormant branches of 80 pomegranate cultivars as experimental materials from 7main producing areas, then evaluating their cold resistance using relative electrical conductivity methodand Logistic equation. We hope select the pomegranate resources with more tolerant to low temperatureswhich can be used as suitable crossing parents for new varieties with cold hardiness.【Methods】Putting annual dormant branches of 80 pomegranate cultivars into the cold incubator for -4, -8, -12, -16, -20 ℃five different low temperatures stress processing, each temperature processed for 24 hours. We measuredthe change of relative conductivity (REC) by low temperatures stress and calculated half-lethal temperature(LT50) by using Logistic equation in SPSS.19. The order of cold resistance was analyzed according to the LT50.【Results】The relative conductivity increased with the intensification of low temperature stress, the range ofthe half-lethal temperature distribution was -7.41 to -12.54 ℃. The half-lethal temperature distributes be⁃tween the -7 ℃ to -8 ℃ with five varieties, -8 ℃ to -9 ℃ with eighteen varieties, -9 ℃ to -10 ℃ with thir⁃ty varieties, -10 ℃ to -11 ℃ with eighteen varieties, -11 ℃ to -12 ℃ with seven varieties. The half-lethal temperature of‘Xinjiang Hongpi’is the highest, and the lowest is‘Tunisia’.【Conclusion】Among 80pomegranate varieties, the most resistant is‘Xinjiang Hongpi’, the lowest resistant is‘Tunisia’.