三系杂交水稻优质育种

按照我国优质稻谷标准，当前三系杂交水稻的米质问题主要表现在整精米率低、垩白粒率高、垩白大及胶稠度低（硬），这与它们的亲本米质状况是一致的。多数水稻品质性状兼有质量、数量性状双重遗传特性，其共同处是杂种F1表现双亲中值，一些品质性状间存在显著相关，品质性状的表现受环境气候尤其是结实期气温的影响极大，不同品种的同一性状对环境的敏感性有差异。谷粒小粒形可减少晋白，利于提高整精米率，并减少受环境的影响。个别品质性状与产量存在相关，综合米质表现与产量却无显著关系。高产与优质是可以结合的，杂交水稻不育系的改良以提高胶笛度和减少晋白为重点，恢复系的改良以减少晋白为主，收集和筛选高（软）胶稠度、小或无垩白、品质性状对气温反应不敏感的品种作亲本杂交选育小粒形无垩白优质恢复系和不育系，并根据性状互补原则可配制出碾磨、外观及蒸煮食用品质均优质的杂交稻组合。

Quality breeding in three-line hybrid rice

According to Chinese national Standards for fine qual ity rice,current problems in connection with milled rice quality of hybrid rice are low h ead rice rate,high chalky ratio,large chalky area and low gel consistency (hardn ess),which conform themselves to their parental lines.Most of the quality traits in rice are of qualitative-quantitative dual heredity,their common phenomenon i s that the F1 hybrid produces the mean value of its parents.There exist signi ficant correlations among some quality traits.The performance of quality traits is highly influenced by environmental climate,especially the temperature during grain filling stage.But the sensitivity of the same trait is different from vari ety to variety.Generally,small grains have less chalkiness,high head rice rate a nd slight environment effects.Although individual quality trait correlates with yield,the total performance of rice quality has little correlation with yield.H ight yield can combine with fine quality.The CMS improvement should focus on the increase of gel consistency and the decrease of chalkiness,while the restorers, on the decrease of chalkiness,too.For developing combinations characterized by good milling,looking,cooking and eating,it is essential to follow the trait comp lementary principle and breed fine quality restorer and CMS lines with small and chalkiless grains,which can be achieved by collecting and selecting the varieti es characterized by high gel consistency,little or non-chalk and climatic-insen sitive quality traits as parents.