Study On Frost Indicators In Diferent Developmental Stages Of Wine Grapes And Peaches In Ningxia

In order to improve frost monitoring,prediction assessment and defense capabilities,and to guide the scientific layout of wine grape and peach orchards in Ningxia.This study had been carried out at Ningxia Zhengguo Agricultural Development Co.,Ltd.and Yinchuan Chateau Mihope from April to May in 2022.The experimental materials were two wine grapes(’Cabernet Sauvignon’ and’Chardonnay’)and two peaches(’Huayu’ and ’Ruiguang 39’).The field frost test chamber was used to simulate low temperature environment and carry out in-situ tests at different developmental stages of wine grapes and peaches.Four treatment temperatures were set for each developmental stage,and lasting 0.5 h.Samples from the natural state of each developmental stage were used as controls(CK),and the freezing rate of organs in the pompom stage,bud opening stage,leaf spreading stage,and new growth stage of wine grapes and the bud stage,blooming stage,bean fruit stage,and young fruit stage of peaches were investigated under different low temperature treatments.We also established a model for the relationship between the freezing rate and low temperature,and obtained the critical temperatures for light,moderate and heavy freezing at different developmental stages of wine grapes and peaches,and then combined with indoor microscopic observations and physiological and biochemical indicators to analyze the resistance to low temperature at different developmental stages of wine grapes and peaches.The main results are indicated as follows:1.Between the same trees,the tolerance of 2 wine grape varieties to low temperature was shown as ’Cabernet Sauvignon’>’Chardonnay’;the cold resistance of 2 peach varieties was ’Huayu’>’Ruiguang 39’.Among the same varieties,the cold resistance of wine grapes at different developmental stages was pompom stage>bud opening stage>leaf spreading stage>new growth stage,and the cold resistance of peaches at different developmental stages was bud stage>blooming stage>bean fruit stage>young fruit stage.2.In-situ tests showed that the frost indicators of wine grapes at different developmental stages:’Cabernet Sauvignon’ had a critical temperature of-7.7℃ for heavy freezing at the pompom stage;-4.5℃ for heavy freezing at the bud opening stage;-2.8℃ for heavy freezing at the leaf spreading stage;and-1.6℃ for heavy freezing at the new growth,which was the weakest resistant to frost.The critical temperature for heavy freezing at the pompom stage of’Chardonnay’ was-5.8℃;bud opening was at-3.2℃ for heavy freezing;leaf spreading dropped to-2.6℃ for heavy freezing;new growth was at-2.3℃ for heavy freezing.3.In-situ tests showed that the frost indicators of peaches at different developmental stages was-4.4℃ at bud stage,-3.3℃ at blooming stage,-2.7℃ at bean fruit stage,and-2.4℃ at young fruit stage.The critical temperature of’Ruiguang 39’ was-4.0℃ for heavy freezing at bud stage;-3.4℃ for heavy freezing at blooming stage;-2.2℃ for heavy freezing at bean fruit stage;and-1.4℃ for heavy freezing at young fruit stage.4.In conditions where in-situ tests could not be used to identify frost indicators,it was recommended that wine grapes used semi-lethal temperature as the critical temperature for moderate frost;peaches used semi-lethal temperature as the critical temperature for light frost.The temperature of the overcooling point was too low to be used as a critical temperature for frost indicator identification.5.The frost temperature indicators for different developmental stages of wine grapes and peaches obtained in this study were established based on actual field tests and were consistent with the actual cultivation performance in industrial orchards.It is recommended that the indicators can be used as a temperature reference for frost defense in production practice.