Abstract: Chemical mutation was an effective way of creating new germplasm resources. To analyze the impact of chemical mutagenesis on AS-9 maize inbred offspring, the salt tolerance and genetic variation between mutant M4 and the corresponding original material (AS-9) were evaluated by using 44 pairs of SSR markers that may be associated with root traits. Seed germination, bud length and root number of M4 were higher than that of AS-9. After treatment with 200 and 250 mmol.L^-1 NaCl for 7 days, root numbers of IV400 and IV1600 seedlings were higher than that of AS-9, with increases of 23.1% and 19.1%, respectively.IV1600 primary root lengths of 1, 2, 3 were 1.33, 1.70, and 2.15 times longer than that of AS-9, respectively. Twenty five pairs of SSR primers gave profiles amplified in sample of M4 mutants, accounting for 56.82% of the total pairs of primers. The average value of genetic similarity coefficient between IVCK and M4 was 0.6563. With the centered genetic similarity coefficient of -0.04 by UPGMA, the maize inbred line materials were divided into three groups: the original material (IVCK), the M4 mutants including IV1400, IV1600, IV2000, and other M4 mutants (IV200, IV400, IV800, IV1200). Principal component analysis and clustering results were similar. In addition, SSR-PCR products amplified by six pairs of primers were sequenced, the results showed that there was distinct variation between AS-9 and the induced M4, indicating chemical mutagenesis made maize inbred AS-9 produce a wide range of genetic variation.

Key words: maize, inbred lines, chemical mutagenesis, SSR markers, genetic variation

摘要： 以玉米基础自交系(AS-9)及其化学诱变自交系M4为实验材料进行耐盐性鉴定，同时利用44对可能与根系性状有关联的SSR引物进行遗传变异分析。结果表明，诱变M4幼苗经200和250 mmol·L-1 NaCl盐胁迫处理7 d后，IV400、IV1600根数比AS-9对照分别增加23.1%、19.1%，诱变IV1600初生根1、2、3根长分别为对照的1.33、1.70、2.15倍；同时在M4玉米试材中扩增出多态性条带的引物25对，占引物总数的56.82%；诱变自交系M4与AS-9的遗传相似系数平均值为0.6563，遗传相似系数中心化后，数据在-0.04处可把材料分为三个类群，基础材料AS-9为Ⅰ类，M4代IV1400、IV1600、IV2000聚为Ⅲ类，其余诱变系为Ⅱ类。此外，6对引物的SSR-PCR产物进行序列差异检测，结果产生新的基元和基元重复次数变化，说明系列化学诱变已使玉米自交系AS-9产生了显著的遗传变异。

关键词: 玉米, 自交系, 化学诱变, SSR标记, 遗传变异