马铃薯普通栽培种杂交后代抗寒性分析

摘要

马铃薯栽培种喜冷凉，但不耐霜冻，几乎无抗寒性。利用苗期抗寒性直接鉴定法，对137个普通栽培种杂交组合的16068个后代进行-3℃抗寒筛选，结果表明，绝大部分杂交后代不耐-3℃的低温，平均存活率为2.81%，以存活率大于5%为标准，筛选出相对“抗寒组合”26个，涉及到“抗寒母本”13个和“抗寒父本”7个；然后辅以电导率法测定相应的“抗寒组合”的“抗寒母本”和“抗寒父本”的半致死温度（LT50）并与预测的“抗寒亲本”的存活率进行相关性分析，结果表明，经筛选出的“抗寒母本”和“抗寒父本”确实有较低的半致死温度，相关性呈现极显著水平。以此为依据，可将所有杂交组合分为3类，其中双亲定义为“抗寒”的组合，其后代出现抗寒株系的比例远高于平均水平，而亲本均为“敏感”杂交组合，其后代存活率远远低于平均水平，说明抗寒杂交育种时最好选用抗寒双亲，这样获得抗寒后代的可能性较大。%The potato cultivars acclimate to cool or temperate climates, normally without tolerance to frost. In this study, 16 068 hybrids derived from 137 cultivar crosses were screened for their tolerance to-3℃at the seedling stage. Results showed that most hybrids died at-3℃, with an average survival rate of 2.81%. If the survival rate criterion was set at 5% or more, in total 26 crosses could be identified, which came from 13 freezing-tolerant female parents and seven freezing-tolerant male parents. Then, the semi-lethal temperature (LT50) of these parents was tested and correlation analysis of these data was made with the predicted survival rate of freezing-tolerant parents. Results showed that these freezing-tolerant male and female parents indeed had low LT50 and the correlation was highly significant. Thus, all the crosses were divided into three classes, of which the survival rate of hybrids from freezing-tolerant parents was considerably higher than the average. In contrast, the survival rate of hybrids from freezing-sensitive parents was considerably lower than the average. These results illustrated that it was better to use freezing-tolerant parents to breed potato against frost, which was more likely to harvest freezing-tolerant hybrids.