中文摘要：

利用收获时种子发芽率和面粉降落值法，于2000-2002年2个小麦种植年度，研究了黄淮、北部、长江中下游、西南冬麦区和东北春麦区1950年以来的781个主要推广品种和新品系的穗发芽抗性。结果表明，小麦穗发芽抗性测定值在年度间极显著或显著正相关，不同年代小麦品种的穗发芽抗性差异较大。1990年以来育成品种的穗发芽抗性与20世纪80年代相近，但明显弱于50、60以及70年代。黄淮、西南和春小麦3个麦区种子发芽率低于2％的高抗品种数分别占各自麦区供试总数的1．7％、4．5％和5．7％，而长江中下游和北部2个冬麦区的种子发芽率都在10％以上；东北春麦区品种的抗性较强，种子发芽率平均为11．2％。利用等电聚焦电泳从发芽率和降落值均偏低的品种中鉴定出异源2号、蜀万24、蜀万761、陕160、孟县4号、京411、京9428、鉴26、燕大1817、农大45、衡水6404、晋麦5号、8号、鄂麦14和克辉等15个携带迟熟α-淀粉酶基因的品种，分布在5个不同麦区。对这些品种及其亲本进行SSR分子标记分析，发现有些与其亲缘关系密切的品种，却不携带迟熟口．淀粉酶基因。上述结果说明，该基因在我国五大小麦产区均有分布，但具该基因的品种数量少，占供试品种数的1．9％，通过育种程序容易选择出不携带该基因的小麦品种。

英文摘要：

Preharvest sprouting resistance in 781 leading wheat varieties since 1950 in Yellow and Huai River Valley Winter Wheat Region, the North Winter Wheat Region, the Southwest Winter Wheat Region, the Yangtze River Winter Wheat Region and the Northeast Spring Wheat Region of China was evaluated by testing the sprouting percentage（ SP） and falling number（FN）of mature seeds during 2000-2002 planting seasons. The results indicated that there was highly positive and significant correlation among years. The resistance to preharvest sprouting in the cultivars from the 1980s and the 1990s was lower than those from the 1950s, the 1960s and the 1970s. Cultivars with sprouting resistance from Yellow and Hnai River Winter Wheat Region, the Southwest Winter Wheat Region and the Northeast Spring Wheat Region accounted for 1.7 %, 4.5 % and 5.7 % of total, respectively. The GP of cultivars in the North Winter Wheat Region and the Yangtze River Winter Wheat Region was above 10%. The sprouting resistance in the Northeast Spring Wheat Region was higher than that in other regions. Meanwhile, 15 cultivars, i.e. Yiyuan 2, Shuwan 24, Shuwan 761, Shan 160, Mengxian 4, Jing 411, Jing 9428, Jian 26, Yanda 1817, Nongda 45, Hengshui 6404, Jinmai 5, Jinmai 8, E＇ mai 14 and Kehui, in different regions with late maturity a-amylase （LMA） gene were selected based on the analysis of isoelectric focusing（ IEF） pattens from those with lower SP and FN （Table 6）. Furthermore, the genetic relationship between wheat genotypes prone to LMA was analyzed based on SSR markers. It was showed that some wheat genotypes, which were quite closely related to genotypes with LMA gene, did not carry the LMA gene. These results suggested that wheat genotypes with the LMA gene were distributed widely in Chinese wheat regions but with low frequency （ 1.9 % ）. So cultivars without LMA gene may be easily selected in wheat breeding programs.