【作者】 朱燕；

【导师】 梁康迳；

【作者基本信息】 福建农林大学 ， 作物遗传育种， 2004， 硕士

【摘要】 选用6个不同类型的水稻品种（系），按不完全双列杂交设计（6×5）配制成一套包括亲本和F₁2个世代的遗传材料。采用包括种子、细胞质、母体植株三套遗传体系的种子遗传模型和统计分析方法，系统分析了不同环境条件下水稻稻米汞、砷、铬、镉和铅等5个重金属元素含量的遗传特性。主要结果如下： 遗传方差分析结果表明，5个重金属元素含量除了受制于种子基因效应、细胞质基因效应和母体植株基因效应等遗传主效应外，还会明显受到各遗传效应与环境互作效应的影响。其中，汞元素含量主要以遗传主效应为主，砷和铬元素含量则以基因型与环境互作效应为主，镉和铅元素含量的遗传主效应和环境互作效应基本相近。在各遗传体系中，汞元素含量以显性效应及其与环境互作效应为主，种子基因效应也有一定作用。砷、铬和镉元素含量则以种子加性与环境互作效应和母体显性与环境互作效应为主，细胞质基因效应及其与环境互作效应对这3个元素含量的影响也较为重要。 遗传率和选择响应分析结果表明，汞、砷、铬和镉元素含量的总狭义遗传率较高，世代的遗传传递力较强，在鉴定筛选淘汰时，需要加大群体才能达到降低这4种元素含量的育种目标。铅元素含量总狭义遗传率最低。5个重金属元素含量的总选择响应可达42.08％～131.5％，通过选择要降低稻米重金属元素含量，需要加大群体，采用适宜的育种方法。汞和铅元素含量宜采用单粒选择法、铬和镉元素含量宜采用单株选择法、砷元素含量宜采用单株和单粒选择法相结合的方法进行筛选鉴定效果较好。 杂种优势分析结果表明，汞、砷、铬元素含量均表现正向的群体平均优势，以铬元素含量的正向群体平均优势最大，达25.3％。镉、铅元素含量则表现负向的群体平均优势，以镉元素含量的负向群体平均优势最大，达15.2％。环境互作群体平均优势在早季表现为负向，在晚季除了镉元素含量为负向外，其余4个元素含量均表现正向，说明在早季利用杂种优势有利于降低重金属元素含量，尤其是降低镉元素含量更能奏效。 遗传协方差分析结果表明，5个重金属元素含量间的基因型协方差均为正向。在各遗传体系中，成对元素含量间均呈现不同程度的正向或负向的遗传协方差和环境互作协方差。在育种利用上，需要针对不同遗传体系控制的遗传相关性，采用不同的筛选鉴定方法，才能达到降低稻米重金属元素含量的育种目标。更多还原

【Abstract】 Analysis on seed, cytoplasmic and maternal genetic effects for the contents of heavy metals such as Hg, As, Cr, Cd and Pb was conducted by using genetic models for quantitative traits of seed in cereal crops. According to incomplete diallel cross design(6 X 5), parents and F| generations derived from six different types of rice varieties (parental lines) were used for this experiment. The main results were as follows.Analysis on genetic variance showed that all the traits of 5 heavy metal contents involved were not only controlled by genes of seed, cytoplasmic and maternal plant simultaneously, but also affected obviously by genetic effects and GE interaction effects. The genetic main effects of Hg contents were more important than others, while As and Cr contents were mainly affected by GE interaction effects, the genetic main effects and GE interaction effects of Cd and Pb contents were almost near. In genetic systems, dominant effects and dominant interaction effects of Hg contents were main, the genetic effects of seed had some effects on it. As, Cr and Cd contents were mainly affects by additive interaction effects of seed and maternal dominant interaction effects, and cytoplasmic genetic effects and cytoplasmic genetic interaction effects also had a important role.The results of heritability and selective response analysis indicated that the contents of Hg, As, Cr and Cd contents was higher, so these four elements had stronger inheritance transfer ability. Large populations were required to decrease their contents, which was helpful to breeding objective in identification and elimination through screening. The contents of Pb had the lowest total heritability in narrow sense. The total selective response of 5 metal elements was 42.08%~131.5%.In order to lower metal contents, we should rely on large populations and proper breeding methods. For Hg, single seed descent method is better; for Cr, single plant selection, while for As, the combination of the two methods mentioned above may be effective to identification and screening.Based on heterosis analysis, it was indicated that Hg, As and Cr contents had positive population means, Pd contents is 25.3% and ranked the first place. Cd and Pb contents had negative population means, among which Cd contents had the highest one of 15.2%. In early season, heavy metal contents had negative population means of GE interaction. In late season, the means were positive except Cd. It showed that the utilization of hybrid heterosis could2significantly help to reduce heavy metal contents especially for Cd.Analysis on genetic covariance proved that genotype covariance was detected to be positive between these 5 heavy metal contents. Genetic covariance and GE interaction covariance were positive or negative to different degrees between pairs of element contents. Different methods of screening and identification were used in breeding program according to genetic relationship which was controlled by different genetic system, in this way the breeding objective of decreasing heavy metal contents can be reached.更多还原