玉米自交系芽期耐冷性鉴定

低温冷害是北方春玉米区主要的气象灾害之一。通过种子低温发芽试验对8个东北地区生产上主要利用的玉米自交系进行芽期耐冷性鉴定。在常温（25℃）和低温（10℃）条件下分别测定了发芽势、发芽率、平均发芽时间、发芽指数、幼苗干重和活力指数等,并以各性状低温与常温下测定值的比值（相对值）作为耐冷性鉴定指标。通过聚类分析将自交系分为耐冷性强中弱3类,其中PH4CV、吉419和吉495耐冷性强,H21耐冷性中等,W9706、黄早四、丹黄02和四279耐冷性弱。相关性分析表明,相对发芽率、相对发芽指数、相对幼苗干重与相对活力指数呈极显著相关,可以作为玉米自交系芽期耐冷性鉴定指标。本试验为大规模鉴定和筛选芽期耐冷玉米种质奠定了基础。

Identification of Cold Tolerance at Germination Stage in Maize Inbred Lines

Cold stress is one of the major meteorological disasters in the spring maize-growing area in northern China. Cold tolerance of eight inbred lines widely used in northeastern China was evaluated through a laboratory germination experiment under low temperature stress. Germination potential, germination rate, average time to germination, germination index, dry weight of seedlings, and vigor index at normal temperature (25℃) and low temperature (10℃) were measured, respectively, and the ratios (relative values) of trait values at low temperature to those at normal temperature were used as indicators for cold tolerance. The cluster analysis revealed that the eight inbred lines could be classified into three groups: PH4CV, Ji 419, and Ji 495 belonged to high cold tolerance, H21 belonged to intermediate cold tolerance, and W9706, Huangzaosi, Danhuang 02, and Si 279 belonged to low cold tolerance. The correlation analysis showed that the relative values of germination rate, germination index, dry weight of seedlings, and vigor index were highly significantly correlated with each other, and they were suitable indicators for cold tolerance. This experiment provided guidance to identify and screen maize germplasm with cold tolerance at the germination stage on a large scale.