Abstract: 【Objective】Salt tolerance of 278 naked oat accessions from different ecological zones at germination stage were comprehensively evaluated in order to provide a guide for identification and evaluation of salt tolerance of naked oat, and supply abundant materials of salt tolerance for breeding of salt tolerance as breeding parents.【Method】Identification for salt tolerant germplasm of naked oat was conducted in an artificial climate incubator with germination method on paper in petri dish under 1.2% NaCl aqueous solution and distilled water, respectively. The culture condition was constant temperature 25℃, relative humidity (70±5)%, 12 h light (6:00-18:00), light intensity 150 μmol?m-2?s-1 in the incubator. When the length of radicle was equal to that of kernel at least, and the shoot height was not less than 1/2 of seed length, the seed was considered as germinated. Germination potential of tested accessions was counted after 96 hours cultivation. Final germination rate, length of the longest primary root and seedling height were measured after 168 hours cultivation. These four traits were used to identify salt tolerance of tested accessions. Based on salt tolerance coefficients derived from four identification indices, the weight of each index was allocated according to variation coefficient of membership function value of four salt tolerance coefficients, and 278 naked oat accessions were evaluated for salt tolerance with the weighted membership function method and classified through cluster analysis.【Result】Compared with distilled water control, germination potential and germination rate of all accessions were declined except SHX88 and NM47, and the root length and seedling height of all accessions were suppressed by salt stress. There were differences among tested accessions based on the four kinds of identification indices. With the weighted membership function method and cluster analysis, salt tolerance of 278 naked oat accessions were comprehensively evaluated and categorized into five grades. Seventeen accessions were highly salt tolerant, 114 accessions were salt tolerant, 106 accessions were middle tolerant, 25 accessions were susceptible and 16 accessions were highly susceptible. Germination potential and germination rate were closer with salt tolerance at germination stage among the four identification indices, but germination rate was more variable than germination potential among tested accessions.【Conclusion】Germination rate is an efficient identification index for rapid identifying and preliminary screening of salt tolerant accessions. The weighted membership function method has good application value in the comprehensive evaluation of tolerance of naked oat to salt stress. SHX75 and other sixteen naked oat accessions which are highly tolerant to salt stress have provided a basis for breeding, cultivation and mechanism research of salt tolerance.

Key words: Avena nuda L. , germination stage , salt tolerance , comprehensive evaluation , screening