Study on evaluation method for cold resistance of grape cultivars and rootstock

【Objective】The objective of the study was to seek appropriate evaluation method for cold resis-tance of grape cultivars and rootstock.【Methods】‘Beibinghong',‘Zuoshan1',‘Beta'and‘Shuang-hong'were taken as the experimental materials to research the physiological indexes related to cord-har-diness including relative electric conductivity(REC) and the contents of soluble sugar,MDA,solubleprotein and free proline under different low temperature treatments. Comprehensive estimation of branchcold-hardiness was made through electrical conductivity method and subordinate function analysis.【Re-sults】The REC and the content of MDA increased as the‘S'type curve as temperature decreased,andthe other indexes changed as single peak curve as temperature decreased. The average subordinative levelof all indexes had significant relationship with these physiological indexes. The results of comprehensiveevaluation were almost in agreement with the semi-lethal temperatures(LT₅₀) of the four cultivars,whoseorder of cold-hardiness from strong to weak was‘Zuoshan1',‘Shuanghong',‘Beta'and‘Beibing-hong'.【Conclusion】The change curves on the average subordinative level of physiological indexes wouldmore comprehensively and reliably reflect the essence of cold- hardiness differences and the tolerablefreezing temperature limit of branches of grape cultivars and rootstock.