| A diallel design with eight parents of Brassica napus were conducted to analyze the threonine (Thr), methionine (Met), valine (Val), phenylalanine (Phe), isoleucine (He), leucine (Leu), lysine (Lys), Aspartic acid (Asp), Glutamic acid (Glu), Serine (Ser), Histidine (His), Glycine (Gly) and Arginine (Arg) contents of rapeseed, by using the genetic model including the diploid embryo effects, cytoplasmic effects and diploid maternal effects for quantitative traits of seed for diploid plant. The objective of the present study was to clarify the genetic effects from embryo, cytoplasm and maternal plant, to estimate the narrow-sense heritabilities from different genetic systems, to analysis heterosis for amino acids of 楼2 rapeseed, to evaluate the genetic correlations among amino acids of rapeseed and between 13 amino acids contents and plant agronomic traits of Brassica napus L. The breeding value of parents for improving these quality traits was predicted in order to find the better parent(s) in rapeseed breeding program. The main results were as follows:1. The performance of amino acid contents were simultaneously controlled by the genetic effects from the diploid embryo nuclear genes, cytoplasmic genes and maternal plant nuclear genes. The contents of Thr, Met, Phe, He, Glu, Gly and Arg in rapeseed were mainly controlled by the maternal effects, while the cytoplasmic effects were more important among different genetic systems for Val, Leu, Lys and Asp. The content of His was mainly controlled by embryo muclear genes. But embryo nuclear effects, cytoplasmic effects and maternal plant nuclear effect were equel important for Ser. Additive and cytoplasmic effects were the major contributions of genetic variation for the content of Thr, Val, Phe, He, Leu and Lys, but embryo and maternal dominance effects were more important for Met, His and Ser of rapeseed.2. The maternal heritabilities were larger than embryo or cytoplasmic heritabilities for Thr, Met, Phe, lie, Glu, His, Gly and Arg, but the cytoplasmic heritabilities were found to be more important than others including Val, Leu, Lys, Asp and Ser in rapeseed.3. The prediction of embryo, cytoplasm and maternal genetic effects of 8 parents showed that Tower was better than other parents for improving the content of essential amino acids in rapeseed; but Zhongyou 821 could decrease most of the essential amino acids in rapeseed because of the negative total genetic effects. The parent of Zhong R-888 could increase the content of nonessential amino acids in rapeseed, which was the better parent for improving most of the content of nonessential amino acids,; but the parent, Yunyou 8, could decrease the content of Asp, Glu, Ser, Gly and Arg in rapeseed, which was not suitable used as parent in quality breeding for improving these amino acids of rapeseed.4. The results of heterosis analysis indictated that the embryo heterosis, cytoplasmic heterosis and maternal heterosis were all important for the performance of 13 amino acids contentin rapeseed crosses. In general, the total heterosis for Lys traits was positive and the lys trait in Fa seed could be increased by the heterosis, while the heterosis for Thr, Met, Val, Phe, He, Leu, Asp, Glu, Ser, His, Gly and Arg were negative and the heterosis could decrease these 12 amino acid traits.5. The significantly positive phenotypic correlations and genotypic correlations were detected between Thr and Met, Val, Phe, He or Leu; Met and lie or Leu; Val and Phe or He; Phe and He or Lys; His and Asp, Ser or Glu; Asp and Thr or Val; Glu and He; Ser and Thr; His and Thr, Met, Val, Phe, He or Leu; Gly and He. It was suggested that the breeding materials could be simultaneously improved with these amino acid in rapeseed. For the relationship between Met and Lys; Ser and Val, He, lys, Asp or Arg; Arg and Thr, Val, Phe, lie, His, Gly; Glu and lys; it was found that genetic correlations were significantly negative. So it was difficult to increase the these amino acid of the rapeseed at the same time. For other pai...
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