Six

Five parental rice varieties with differentt allelopathic potentials were used for diallel cross based on [P P+1 /2] design to get genetic materials including parental lines and two generations of F1s. The dynamics of heterosis for allelopathy in rice at different leaf stages was analyzed using additive-dominant developmental genetic model. The results showed that heterosis in both F1 and F2 was inhibitory to shoot and root length of lettuce (Lactuca sativa L). The heterotic effects in allelopathy varied with the leaf stage of rice accession. Simultaneous backcrossing and selfing breeding method was used to develop the hybrid rice with allelopathic activity and the isogenic hybrid rice with non-allelopathic effect on weeds. It was also indicated that heterotic effect on allelopathy in rice was positively-significant, showing higher heterosis over midparent. This hybrid rice had the additive suppressive effect on the target weed barnyardgrass, exhibiting a large deviation from the resource competition curve. Thus we improved the genetic performance of the trait in this hybrid combination for commercial use.

The

采用包括基因型与环境互作的数量性状加性-显性发育遗传模型，研究了按双列杂交设计｜P(P+1)／2｜配制成1套包括亲本、F1两个世代的水稻遗传材料在不同环境条件下化感作用的动态杂种优势。结果表明，杂种F1和F2在大部分叶龄时期具有抑制受体植物茎长和根长的杂种优势。F2的化感作用潜力与FI相比有所下降，在不同环境条件下其群体平均优势均为F1的1／2。在温度较低、光照较弱的田间环境条件下，水稻化感作用杂种优势较大。暗示着环境胁迫会增强化感作用的性状表现，解释了植物在不利环境下产生化感物质数量有所增加的遗传原因。

介绍了1O多年来在水稻产量形成的发育遗传及其分子生态学基础的研究成果，分析了传统上应用比较生理学研究作物高产形成的优点与不足，强调应积极引进其它学科的研究内容及其方法，深化对作物栽培科学问题的认识。提出了根据作物不同发育阶段的基因作用规律及其性质，研究制定相应措施，及时调控那些受显性遗传效应机制和加性效应基因与环境互作同向表达的性状是实现高产稳产的技术关键，认为这是作物遗传生态栽培学的主要特色与技术创新。并就作物栽培向分子栽培学的发展及其前景作了初步探讨。