Evaluation on cold resistance of 10 rose germplasms

【Objective】The study aimed to explore the physiological characteristics of different rose germplasm’s response to low-temperature stress.【Method】The dormant branches of 10 one-year-old roses were used as experimental materials,which included Rosa spp.Rosoideae （R₁）,Damask rose Mill（R₂）,Rosa centifolia L.（R₃）,Rosa damascera L.（R₄）,Rosa rugosa（R₅）,Rosa rugosa‘Zi zhi’（R₆）,Rosadamascera‘Baojialiya Hong’（R₇）,Rosa rugosa Var.typica Reg（R₈）,Rosa‘Shang shui’（R₉） and Rosa canina L(R₁₀).They were treated with different low temperature stresses（-10℃，-15℃and-25℃），with5℃as the control.Additionally,physiological indexes such as relative electrical conductivity（REC）,superoxide dismutase（SOD） activity,soluble protein content,peroxidase（POD） activity,soluble sugar content,free proline（Pro） content and malondialdehyde（MDA） content were determined.To select the best coldresistant rose germplasms,the comprehensive evaluation was carried out by using Principal Component Analysis.【Result】The POD activity,soluble protein,soluble sugar,MDA and Pro contents of the 10 rose germplasms all showed an trend of increasing first and then decreasing as the temperature decreased;the REC exhibited a trend of gradually increasing except for R₂,R₅ and R₉;the SOD activity gradually increased first and then decreased except for R₃ and R₇,of which the SOD rose continually.Three principal components with eigenvalues＞1 were extracted （eigenvalues were 2.526,1.38 and 1.198）,and their variance contribution rates were 42.105%,23.002%and 19.965%,respectively,and the cumulative contribution of variance reached 85.07%.Based on the scores of principal components,the cold resistance of 10 rose germplasms ranked as follows:R₃＞R₇＞R₄＞R₁₀＞R₁＞R₆＞R₈＞R₅＞R₉＞R₂.【Conclusion】Under the stress of low temperature,Rosa centifolia,R.damascera‘Baojialiya Hong’and R.damascera were the strongest in cold resistance,R.canina,R.spp.Rosoideae,R.rugosa‘Zi zhi’and R.rugosa Var.typica were medium,and R.rugosa,R.‘Shang shui’and Damask rose were the weakest in cold resistance.