Investigation On Freezing Injury Of Peachvarieties In Hebei Province And Evaluationof Cold Resistance Of Some Varieties

Hebei Province is the main peach producing area in China,In addition to the cold areas in the north,130 counties and districts in Hebei Province have peach distribution and planting.In January 2021,the low temperature occurred once in decades in Hebei.In order to find out the freezing condition of each peach variety after low temperature and the cold resistance of the main varieties in Hebei Province,field investigations were carried out in various places by means of field investigation and questionnaire survey,and the annual dormant branches of 14 peach varieties treated with low temperature were used as test materials,The content changes of relevant physiological indexes in peach branches,comprehensively analyze and compare the differences of cold resistance among different peach varieties,comprehensively analyze and rank all cold resistance indexes by using the membership function method,and provide a basis for the selection of peach varieties and regional cultivation in Hebei Province according to the analysis results.1.Field investigation results show that:(1)Among the 60 varieties investigated in the field,20 varieties did not suffer from freezing injury,and 40 varieties suffered from freezing injury to varying degrees.The freezing injury area was 28300 mu,accounting for 2.18% of the peach cultivation area in that year.(2)Different varieties have different cold resistance,and the performance of freezing injury(degree of freezing)in different areas was different.At the same time,it was also affected by the terrain.(3)The average freezing injury index(cold resistance)of 40 varieties with freezing injury was different.By comparing the average freezing injury index of frozen varieties,it was found that the varieties with less freezing injury were’Jintong5’,’Zhongyoupan9’,’Zhongyou5’,’Zhongyou20’,and the old varieties with a long cultivation history;The varieties with moderate freezing injury include ’Beijing8’,’Bairuyu’,’Zhaohui’,’Chunli’,etc.The varieties with severe freezing injury include’21Shiji’,’Huangjinmi1’,’Huangjinmi4’,’Huangjinmi6’,etc.(4)Compared with the 11 regions with freezing injury,the higher the latitude was,the greater the level of freezing injury was,followed by Handan,Xingtai,Shijiazhuang,Hengshui,Baoding,Langfang,Cangzhou,Tangshan,Qinhuangdao,Chengde and Zhangjiakou.2.The results of low temperature stress treatment showed that:(1)In different low temperature stress treatments,according to the change of electrical conductivity,the cold resistance of 14 peach varieties was ranked from low to high as ’Huangjinmi1’ > ’Laishanmi’ > ’Chunli’ > ’21Shiji’ > ’Zhongpan11’ >’Zhongtaojinmi’ > ’Yufei’ > ’Chunmei’ > ’Yanhong’ > ’Zhongyoupan9’ > ’Jingchun’ >’Qingfeng’ > ’Okubo’ > ’Shijizhixing’.(2)Combining the relative conductivity with logistic curve equation,the calculated half lethal temperature(LT50)can accurately reflect the cold resistance of fruit trees.From low to high,the order of half lethal temperature of 14 peach varieties was ’Huangjinmi1’ > ’Laishanmi’ > ’Chunli’ > ’21Shji’ > ’Zhongpan11’ >’Zhongtaojinmi’ > ’Yufei’ > ’Chunmei’ > ’Yanhong’ > ’Zhongyoupan9’ > ’Jingchun’ >’Qingfeng’ > ’Okubo’ > ’Shijizhixing’.(3)According to the changes of soluble sugar content of 14 peach varieties,the order of cold resistance from strong to weak was ’Shijizhixing’ > ’Okubo’ >’Qingfeng’ > ’Zhongpan11’ > ’Jingchun’ > ’Yanhong’ > ’Yufei’ > ’Chunmei’ >’Zhongtaojinmi’ > ’Laishanmi’ > ’Chunli’ > ’Zhongyoupan9’ > ’21Shiji’ >’Huangjinmi1’.(4)According to the changes of soluble protein content of 14 peach varieties,the order of cold resistance from strong to weak was ’Shijizhixing’ > ’Okubo’ >’Jingchun’ > ’Qingfeng’ > ’Yanhong’ > ’Zhongyoupan9’ > ’Zhongpan11’ > ’Chunmei’ >’Yufei’ > ’Zhongtaojinmi’ > ’Chunli’ > ’21Shiji’ > ’Laishanmi’ > ’Huangjinmi1’.(5)Judging from the magnitude of the decrease in the water content of the branches,the order of the cold resistance of the branches of 14 peach varieties from strong to weak was ’Shijizhixing’ > ’Okubo’ > ’Qingfeng’ > ’Yanhong’ >’Zhongyoupan9’ > ’Jingchun’ > ’Chunmei’ > ’Yufei’ > ’Zhongtaojinmi’ >’Zhongpan11’ > ’21Shiji’ > ’Chunli’ > ’Laishanmi’ > ’Huangjinmi1’.In this study,the comprehensive ranking of cold resistance of 14 peach varieties was obtained by using the membership function analysis method: ’Shijizhixing’ >’Okubo’ > ’Qingfeng’ > ’Yanhong’ > ’Zhongyoupan9’ > ’Jingchun’ > ’Chunmei’ >’Yufei’ > ’Zhongtaojinmi’ > ’Zhongpan11’ > ’21Shiji’ > ’Chunli’ > ’Laishanmi’ >’Huangjinmi1’.