不同时期水稻主要恢复系、不育系的遗传差异变化研究

用AFLP技术分析了我国不同年代广泛应用的野败型杂交水稻19个恢复系和13个不育系的遗传差异，同时基于其农艺性状进行了聚类，结果表明:（1）基于标记和性状两种聚类在不育系和恢复系的区分上一致，而在恢复系内和不育系内的遗传差异检测上有较大差异；（2）我国水稻亲本间的遗传差异较大，且在不育系与恢复系间>恢复系内>不育系内；（3）恢复系内的遗传差异以早期小于中期、近期，其与不育系间的遗传差异也存在同样的关系，这与20世纪80年代中、后期我国杂交水稻产量大幅度提高，90年代后一直徘徊不前的变化趋势一致；（4）不育系内的遗传差异后期大于前期，但它与恢复系间的遗传差异前、后期不显著；（5）不同年代恢复系的分子标记遗传差异变化趋势与杂交水稻产量变化趋势一致，分子标记揭示的遗传差异可为杂交育种中恢复系的选择提供参考。

Genetic Difference Changes of Main Restorer and Sterile Lines in Different Stages of Hybrid Rice (Oryza sativa spp. indica L.)

Heterosis of F₁ hybrid is correlative to genetic distance between its parents, the sterile and the restorer lines, at certain extent. Study on genetic diversity dynamics of widely used sterile and restorer lines of hybrid rice (Oryza sativa spp. indica L.) at different stages will help to choose parents efficiently and to improve hybrid yield. In present research, 31 pairs of AFLP (amplified fragment length polymorphism) primers were used to detect genetic distances of 19 restorers and 13 sterile lines of WA-type hybrid rice that were widely used at different stages. All polymorphic bands were recorded by 0/1 method. Genetic distances (GD) of Nei & Li between all possible pairs of parents were calculated using AFLP data. Chi-square genetic distances between parents were calculated based on the standardized values of 15 agronomic traits of 32 parents. 32 rice parents were clustered based on GD values and on Chi-square distances by UPGMA respectively. The results were as follows: (1) A total of 535 clear polymorphic bands were detected among 32 parents, and on average 17.3 distinguishable bands were observed after amplification with each primer pair. (2) The result of dendrogram based on AFLP markers was similar to that on agronomic traits analyses in grouping of 32 parents of sterile and restorer lines, but a few differences between two dendrograms were detected in diversity among sterile or restorer lines. (3) There were relatively larger genetic differences among 32 parents, and the GDs between sterile and restorer lines were larger than those among restorers as well as among sterile lines. (4) The GDs among early-stage restorers were lower than those among middle-stage and late-stage restorers. Similar trend was observed on the GDs between sterile lines and restorers in 3 stages. These trends were positively correlated with the yield trend of hybrid rice, i.e. the yield of hybrid rice was largely improved in the middle-to-late 1980s and was stunted after 1990s. (5) The GDs among late-stage sterile lines were larger than those among early-stage sterile lines, but the GDs between early-stage sterile lines and restorers showed no significant difference from those between the late-stage sterile lines and restorers. (6) The trend of GDs based on AFLP markers of restorers in 3 stages was similar to yield trend of hybrid rice cultivars. GDs based on molecular makers can be used as one reference in choosing restorers in hybrid crossing.