在水稻发芽期，筛选耐盐性品种的最适NaCl浓度是1.5% 。在这个浓度下，调查了九个亚洲国家的306个品种的耐盐性。参照程氏形态分类法的稃毛标准将参试品种分成籼和粳，籼稻品种比粳稻更耐盐。酯酶(Est)同工酶分析也印证了这一结果。酯酶同工酶的等位基因Est-22、Est-32和Est-41可以用来鉴别籼稻品种，而Est-2°、Est-31和Est-4°可以识别粳稻品种。具有等位基因Est-22、Est -33和Est-41的品种比具有Est-2°、Est-31和Est-4°的品种更耐盐。比较七个酯酶同工酶酶谱的品种耐盐性，发现有70%的具有Est-22的品种在1.5%NaCl浓度下发芽率超过50%。因此，等位基因Est-22可能是品种耐盐性的一个标志。大多数马来西亚的品种是耐盐的，其次为缅甸、中国和孟加拉的品种。大多数泰国、菲律宾和日本的品种对盐敏感%It was concluded that the optimum NaCl concentration was 1.5% for screening salt-tolerant varieties in the germination stage.At thi s concentration, the germination rates of 275 varieties from nine Asian countrie s were investigated.Among the six morphological characters used by Cheng (1988), glume hairinss was the most reliable in Indica-Japonica classification. Indica varieties were more salt-tolerant than Japonica ones. This result corresponded to esterase isozyme analysis.Alleles Est-22，Est-32 and Est-41 were us ed in identifying Indica varieties. Alleles Est-20，Est-31 and Est-40 served as identifying Japonica varieties. Varieties carrying alleles Est-22, Est-32and Est-41 were more salt-tolerant than those carrying Est-2 0,Est-31 and Est-40. According to salt-tolerant comparison among the s even esterase genotypes,the three alleles of locus Est-2 showed quite different associations with respect to the degree of salt tolerance. Seventy percent of t he varieties with alleles Est-22 had more than 50% of germination rate at 1 .5% NaCl.Allele Est-22 seemed to be a marker of rice salt tolerance.Most of the varieties from Malaysia were salt-tolerant,followed by varieties from Thai land,the Philippines and Japan were salt-susceptible.
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