58份桃种质资源抗寒性评价

为了明确58份桃种植资源的抗寒特性，并从中筛选出抗寒性高的种质，以1年生休眠枝条为试材，测定其在4、-3、-6、-9、-12、-15、-18、-21、-24、-27、-30、-33℃ 12个低温处理下的电解质外渗率变化，同时结合Logistic方程，求出半致死温度（LT₅₀）。结果表明，处理温度从4~-33℃，大多数桃种质电解质外渗率变化趋势一致，且在-21℃时出现拐点。58份种质，其半致死温度主要集中在-25～-35℃。来源于高海拔地区的‘2010西藏17号’、‘2010西藏28号’、‘2010西藏32号’、‘2010西藏54号’，抗寒性整体低；来源于西北高旱地区的‘江村4号’、‘丁家坝青皮桃’及选育品种‘夏至早红’，抗寒性在所有测试种质中最高。对于大多数测试种质而言，-21℃可作为细胞膜开始受损伤的临界温度，-21～-30℃，细胞膜损伤程度加大，超过此范围，细胞膜损伤将不会被修复。通过抗寒性评价，筛选出3个高抗资源。

Assessment of the Cold Resistance of Fifty-eight Peach Accessions

Cold resistance of 58 peach accessions was assessed for selecting fine cultivars with high cold resistance.One-year-old dormant branches were stored under different low temperatures (4,-3,-6,-9,-12,-15,-18,-21,-24,-27,-30℃ and -33℃,respectively) to observe the changes of electrolyte leakage ratio (ELR).‘Semi lethal temperature’ was calculated with Logistic equation.The results showed that ELRs of all 58 peach accessions had the similar patterns of variation when temperature declined from 4℃ to -35℃.Most accessions had the declining tendency when treated temperature varied from 4℃ to -3℃,but this tendency turned into smooth and ascending when the temperature varied from -3℃ to -21℃ and -21℃ to -33℃ respectively.‘Semi lethal temperature’ of 58 accessions were mainly confined into -25℃ to -35℃.Cultivar ‘2010 Xizang 17’,‘2010 Xizang 28’,‘2010 Xizang 32’ and ‘2010 Xizang 54’,all derived from Qinghai-Tibet Plateau,had the lowest cold resistance in all tested accessions.‘Xiazhizaohong’ cultivated from Beijing Academy of Agriculture and Forestry,‘Jiangcun4’ and ‘Dingjiabaqingpitao’ derived from Northwest China,all had the highest cold resistance.It was concluded that -21℃ could be used as a critical temperature for cell membrane to be damaged.From -21℃ to -30℃,cell membrane showed serious damage,and exceeding this temperature range,the damage would not be restored.Three cultivars with high cold resistance were screened out.