【作者】 洪舟；

【导师】 施季森；

【作者基本信息】 南京林业大学 ， 林木遗传育种， 2009， 博士

【摘要】 杉木种内杂交存在明显杂种优势,且杂种优势表现与亲本配合力组分、以及作用方式密切相关,但F1组合杂种优势分子机理目前尚不清楚。本研究以8×8杉木杂交组合为材料,从分子遗传学和表观遗传调控对杂种优势的分子机理进行了探讨。其实验结果和主要结论如下:1.生长性状在F1组合之间的差异均达到极显著水平;一般配合力效应和母本效应十分显著,而特殊配合力效应、父本效应、特殊正反交效应则可以忽略;F1的杂种优势与双亲的特殊配合力达到了显著水平的正相关。2.亲本间遗传距离与F1杂种优势在生长和材性性状上相关与材料选择无关;各性状亲本的平均遗传距离与亲本一般配合力、母本效应、父本效应在4个性状上相关显著。3.杉木基因组中至少有22.45%的胞嘧啶位点发生甲基化。杂交组合与其双亲间发生广泛的胞嘧啶甲基化变化;在优势组合杉木36×杉木21中的去甲基化位点数高于在劣势组合杉木21×杉木36中的去甲基化位点数。4.杉木基因组的DNA甲基化模式主要以内侧胞嘧啶的甲基化为主;6个正反交组合总的甲基化百分率相对于亲本的自交组合而言,甲基化率呈减少的趋势;外侧胞嘧啶半甲基化、内侧胞嘧啶甲基化位点变化与杉木树高,胸径和材积性状的杂种优势均成显著负相关。更多还原

【Abstract】 There is an obvious heterosis in the intraspecific hybridization of Chinese fir, and the performance of hybrid combinations is closely to the component of parents’combining ability and the action mode of them, but this is unclear of the molecular mechanism of heterosis of F1 hybrids. To reveal the molecular basis of heterosis and the modification at genetic and epigenetic regulation level of Chinese fir was one of the main intentions. The main results are as follows:1. Significant phenotypic differences were found among the F1 hybrid combinations of Chinese fir for most of the growth characteristics; positive and negative heterosis was measured in all of the characteristics. Significant general combining ability as wel1 as maternal effects were obtained.But specific combining ability,male effects,specific reciprocal effects seem to be negligible. SCA effecting was significantly positive correlation with heterosis.2. The correlation coefficients between GD and heterosis of growth and wooden traits of F1 hybrids were all not significant. The correlation coefficients between average GD and general combining ability, maternal effecting, paternal effecting of four characters for each parent were all significant.3. About 22.45% of the 5’-CCGG sites in the genome of Chinese fir were in methylation. The cytosine methylation patterns between hybrids and their parents were compared, extensive cytosine methylation alterations including hype-and demethylation as well as the potential conversion of methylation types occurred in the hybrid compared with the parents; the demethylation loci that occurred in cross sha36×sha21 were greater than those sha21×sha36.4. The inner-methylation of double-stranded DNA was the main pattern of the genomic DNA methylation on Chinese fir. The methylation percentage at CCGG sites among the six crosses was significantly lower than their parent’s selfing. There were significantly negative correlation between both the inner methylation of double-stranded DNA, outer methylation of single-stranded DNA patterns and the heterosis.更多还原