利用RFLP标记水稻亲本遗传差异及其杂种优势中的利用

本研究以17个杂交水稻亲本、3个新株型株系和24个光壳稻、爪哇稻品种为DNA样品来源，通过RFLP（限制性片段长度多态性，Restriction Fragment Length Polymorphism,简称RFLP）标记技术，研究光壳稻和爪哇稻及其与温带粳稻之间的关系，探索RFLP标记水稻亲本遗传差异在杂交稻育种中利用的可能性。研究结果表明：42个探针共产生69个不同的限制性片段，其中20个（占47.6%）探针显示47个（占68.1%）多态性片段，至少在2个基因型间存在差异。每个具有多态性片段分别以1和0记录存在与否。由RFLP数据计算的Nei‘s遗传距离，创建聚类树状图。聚类分析结果表明，灿稻和粳稻容易被分开，温带粳稻又容易与光壳稻、爪哇稻分开，但光壳稻和爪哇稻混合聚在一起，光壳稻与温带粳稻之间的遗传距离要比爪哇稻与温带粳稻之间的遗传距离大。根据聚类图发现温带粳稻亚群内杂种优势较弱，亚群间即生态群间的杂种优势较强，群间即灿、粳亚种间杂种优势更强。利用光壳稻、爪哇稻选育不同生态群方向的恢复系和不育系，已配组育成了强优势的杂交稻组合。

Genetic Diversity Detected with RFLP Markers among Rice Cultivars (Oryza Sativa L.) and Its Utilizaton in Hybrid Rice Breeding

Seveteen parents of hybrid rice and 3 new plant type lines and 24 Nuda, Javanica cultivars were used to evaluate genetic diversities by RFLP markers between parents. The possibility was explored that genetic diversity estimated from RFLP banding patterns was used in hybrid rice breeding. Results indicated that Forty-two probes using in this study generated 69 different restriction fragments in the 44 varieties. Twenty (47.6%) probes detected 47 (68.1%) polymorphic fragments that were different at least between two parents. Each of those polymorphic fragments were scored 1 for present and 0 for absent. Based on the pair-wise comparisons of restriction fragments the genetic distance was calculated using Nei's genetic distance and a dendrogram was constructed using an unweighted pair group method with arithmetical averages (UPGMA). The indica and japonica cultivars were easily classified into separate groups by cluster analysis, and temperate and tropical japonica cultivars were classified into separate subgroups, too. But Nuda and javanica cultivars were usually clustered in mixed subgroup. In general, a higher level of polymorphism was found between japonica and indica subspecies while fewer polymorphisms were found between Nuda and javanica cultivars within the japonica subspecies, and the genetic distance between temperate japonica and Nuda was further than the genetic distance between temperate japonica and javanica. The results from the dendrogram were found that the economical heterosis between temperate japonica cultivars was low, the heterosis between subgroups was stronger and the heterosis between groups (indica / japonica) was strongest. Making use of Nuda and javanica, parents of hybrid rice as distinct from ecotype were bred, and high-yield hybrid rice combinations had been bred.