【作者】 郭世星；

【导师】 李平； 牛应泽；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2011， 博士

【摘要】 油菜是世界广泛种植的油料作物,在我国种植面积和总产均居世界首位,也是我国重要的食用油来源。油菜籽含油量的高低,油脂中主要脂肪酸成分的含量直接关系到菜籽油的食用营养价值和工业用经济价值。目前油菜籽的含油量平均约41%左右,离理论含油量相差甚远；菜籽油中的主要脂肪酸组分中对人体营养有利的油酸和亚油酸含量较低。因此,提高油菜品种油脂含量,提高油脂中油酸和亚油酸的含量是目前油菜品质改良的目标。甘蓝型油菜是杂种优势利用成功的重要作物之一,探讨油菜含油量杂种优势及其产生的原因,对杂交油菜育种具有重要的实践意义。前人对油菜含油量进行了较多的研究,油酸和亚油酸的研究相对较少,但是不同研究者由于采用的材料和方法不同,其研究结果也有较大的差异。因此,研究含油量及油脂中主要的有益脂肪酸油酸和亚油酸的遗传体系,以及进行QTL定位分析,可进一步丰富油菜数量遗传理论,对油菜品质改良具有重要的理论与实践意义。本研究采用6个含油量有差异的甘蓝型油菜品系,按照Griffing方法Ⅰ配制30个正反交组合,种植于3个不同生态地点,考察种子含油量,分析配合力和杂种优势；选择其中2个亲本(加拿大引进品系CG38,人工合成甘蓝型油菜品系B25),构建组合CG38/B25的P1、P2、F1、B1、B2、F26个世代,利用主基因+多基因混合遗传模型对种子含油量、油酸和亚油酸含量进行遗传分析,探讨三者遗传模式,明确主基因效应、多基因效应及其遗传率；以BC1F1为作图群体,利用SSR、RAPD和SRAP等标记技术,构建甘蓝型油莱分子标记遗传图谱,并对含油量、油酸和亚油酸含量进行QTL定位。其主要研究结果如下：1、36个试验材料种植于3个不同生态地点(其中1个点由于虫害严重缺苗较多未统计),含油量配合力分析结果表明,两地点环境差异较大,含油量的一般配合力(GCA)、特殊配合力(SCA)、反交效应均极显著,三种效应均受到环境的显著影响。含油量广义遗传率较高而狭义遗传率相对较低,且狭义遗传率大于广义和狭义遗传率之差,表明基因的加性效应远比非加性效应对表型变异的贡献更大。含油量的加性效应方差远大于非加性效应和反交效应方差,GCA与环境互作方差较小,SCA和反交效应与环境互作方差较大,证明含油量的遗传以加性效应为主,同时亲本GCA在不同环境中的表现较稳定。2、对36个供试材料进行含油量的杂种优势分析表明,不同组合的中亲优势与超亲优势均具有明显差异,但总体来说,含油量杂种优势相对较低。不同组合在不同环境中的优势变化呈极显著正相关,说明含油量的杂种优势表现具有一定的稳定性。正反交组合含油量的t检验表明有8个组合达到极显著,细胞质效应对杂种含油量的作用不可忽视。3、配合力相关分析表明不同环境下亲本GCA和组合SCA均具有极显著和显著的正向相关关系,亲本GCA的表现相对更稳定。配合力与组合表型值的相关性表明亲本GCA之和、SCA与杂种表型值分别呈极显著及显著的正相关,其中GCA之和的相关程度更高,GCA与SCA相关不显著,不能从亲本GCA的高低来预测其SCA的高低。两地点亲本一般配合力之和与杂种F1含油量杂种优势相关关系均不显著,特殊配合力与杂种F1含油量杂种优势均存在极显著的正向相关关系,且决定系数较高,反映了特殊配合力与杂种优势均由基因的非加性作用引起。4、以加拿大引进品系CG38,人工合成甘蓝型油菜品系B25为供试亲本,两者亲缘关系较远、含油量及其它品质性状差异较大。CG38(P1)、B25(P2)和F1平均含油量分别为41.67%,30.02%和37.04%；油酸平均含量分别为57.51%、36.69%和42.26%,F1偏向低油酸亲本；亚油酸平均含量分别为18.83%,12.98%和13.00%,F1及分离世代均偏向低亚油酸亲本。分离世代B1、B2、F2的含油量、油酸与亚油酸,均表现连续性分布,具有单峰或双峰的正态分布特征,显示为多基因控制的数量性状。含油量最少受6对基因控制,油酸最少受2对基因控制,亚油酸最少受4对基因控制。5、采用主基因+多基因模型分析组合CG38/B25含油量、油酸和亚油酸的遗传特性表明,含油量以D-0模型为最适遗传模型,即受1对加性.显性主基因+加性-显性.上位性多基因遗传系统控制,主基因遗传率为25.81%-67.26%,多基因遗传率为27.12%-44.77%。油酸和亚油酸均以E-0模型为最适遗传模型,即受2对加性.显性.上位性主基因+加性-显性.上位性多基因遗传系统控制。油酸主基因遗传率为67.69%～86.84%；多基因遗传率为0.03%～9.89%；亚油酸主基因遗传率为37.22%～66.37%,多基因遗传率为5.96%～26.09%,表明油酸、亚油酸的遗传均以主基因为主,而亚油酸受环境影响相对较大。6、采用SSR、RAPD和SRAP标记,BCl为作图群体,筛选出具有多态性的SSR引物61对、RAPD引物31条、SRAP引物89对。利用软件MAPMAKER/EXP3.0对筛选出的181个多态性标记进行连锁分析,构建了一张包含20个连锁群的甘蓝型油菜遗传连锁图谱,包括67个SRAP标记、48个SSR标记,21个RAPD标记,共136个多态性标记位点。图谱全长1725.00cM,标记间平均图距15.97cM。7、采用软件QTL Icimapping v2.2的完备区间作图进行QTL分析,对于含油量,检测到2个位点。其中1个位于第10连锁群上的标记SSRRa2-E0和EM15ME14区间,可解释表型变异的4.43%,加性效应0.42%；另1个位于第15连锁群上的标记EM5ME11b和EM12ME14区间,可解释表型变异的18.68%,加性效应-0.60%。检测到2个与油酸含量相关的位点。其中1个位于第15连锁群上的标记EM12ME17和EM9ME10间,可解释表型变异得8.99%,加性效应1.5810；1个位于第20连锁群上的标记AG16和EM17ME15b区间,可解释表型变异的5.31%,加性效应.1.2196。检测到1个与亚油酸含量相关的QTL位点,位于第15连锁群上的标记EM5ME11b和EM12ME14区间,可解释表型变异的9.46%,加性效应0.68。更多还原

【Abstract】 Rape is one of main oil crops widely grown in the word, and in our country,it is an important source to the vegetable oil, the largest planting area and the most products. Economic value of the oil is affected by the content of oil and composition of fatty acid in seed either for edible use or for industrial use.The current average of oil content is about 40%, far from the theoretical oil content, and the content of oleic acid and linoleic acid in seed are beneficial to human, but lower. Therefore, Improving the content of rapeseed oil, oleic acid and linoleic acid are the goal on quality improvement of rape at present.Utilizing heterosis is one of the most effective ways to increase yield and improve quality in crops. Rapeseed is one of the most successful crops in heterosis utilization worldwide. heterosis utilization worldwide. To explore the sources of heterosis for agronomic and quality traits in rapeseed, it will play an important role in hybrid breeding. There were more papers about oil content, the oleic acid and linoleic acid in rapeseed had less research and got different results. Research results on oil content in rapeseed from different authors were different, it might be that different materials and different methods they used in their researches. Study further on inheritance system of oil content, oleic acid and linoleic acid, and mapping QTLs linked to them, could enrich the quantitative genetic knowledge about rapedeed.It will play an important role in quality improvement in rapeseed.In this study,6 pure line varieties from different origins were used to produce 30 hybrids by hand pollination within Griffing model I mating design. These hybrids, together with their parents, were tested for oil content in two different locations. Combining ability and heterosis on oil content were analyzed. A six basic generations (PI, P2, F1, B1, B2 and F2) derived from crosses of CG38×B25 in rapeseed (Brassica napus L.) were used to analyze the inheritance of oil content in seed, oleic acid and linoleic acid in oil, applying the mixed model of major gene plus polygene. And the BC1F1 population was used to construct a genetic map in rapeseed(Brassica napus L.), based on RAPD, SSR and SRAP markers. QTLs linked to oil content, oleic acid and linoleic acid were identified in this population.The main results are as follows:1. The results of combining ability analysis on oil content showed there were the extremely significant difference in two locations, the general combining ability(GCA), specific combining ability(SCA), anti-cross-effects of oil content were extremely significant, and all three effects were significantly affected by the environment. The broad-sense heritability of oil content were relatively higher than narrow-sense heritability, and narrow-sense heritability were higher than the difference between broad-sense heritability and narrow-sense heritability, indicating that the contribution of additive effects to phenotype was much higher than non-additive effects. The variance of additive effects on oil content was much higher than of non-additive effects and anti-cross effect. The less variance of interaction with GCA and the environment, the larger of interaction with SCA, anti-cross and the environment, indicated that additive effect was principal for heredity of oil content, GCA in different environments was more stable.2. The results from heterosis analysis of oil content showed that the mid-parent heterosis and the over-parent heterosis between the tested materials were significant different, but the heterosis was relatively lower. There was extremely significant positive correlation with different hybrid in two environments, indicating the heterosis of oil content had a certain stability. T-test on oil content between reciprocal cross showed there were the extremely significant difference from 8 combinations, and the cytoplasmic effect on oil content could not be ignored.3. Correlation analysis of combining ability showed that there were significant positive correlation on GCA and SCA between two environments. The performance of parental GCA was relatively more stable. Correlation analysis showed that there were significant positive correlation between the sum of parent GCAs, SCA and F1, and the correlation of the sum was higher. The correlation between GCA and SCA was not significant. The correlation between the sum of parent GCAs and heterosis on oil content was not significant. But there was extremely significant positive correlation between SCA and heterosis, indicating that SCA and heterosis were induced to non-additive effect of gene.4. The relationship of CG38, a rapeseed line(B. Napus) introduced from Canada, and B25,a artificially resynthesized rapeseed line(B. napus), was much distantly, the difference of oil content and other quality traits were comparatively large. The average oil content of CG38(P1) and B25(P2) was 41.67%,30.02%, and the average content of oleic acid was 57.51%、36.69%, and the average content of linoleic acid was 18.83%,12.98%. The value of oleic acid and linoleic acid was closer between F1 and the lower parent(B25), that of linoleic acid in three segregating generations was closer to the lower parent(B25). In B1, B2 and F2 population, the three quality characteristics were normal distribution, indicating that they are quantitative genetic traits controlled by multiple genes.The oil content was controlled by at least six genes, oleic acid was controlled by at two genes, and linoleic acid was controlled by at least four genes.5. The heredity of oil content, oleic acid and linoleic acid of the cross CG38/B25 was analyzed with major gene plus polygene model, indicating that oil content was controlled by one additive-dominance major gene plus additive-dominance-epistasis polygene(D-O). The heritabilities of major gene were 25.81%～67.26%, and that of polygene was 27.12%～44.77%. Oleic acid and linoleic acid were controlled by two additive-dominance-epistasis major gene plus additive-dominance-epistasis polygene(E-O). For oleic acid, the heritabilities of major gene were 67.69%～86.84%, and that of polygene was 0.03%～9.89%. For linoleic acid, the heritabilities of major gene were 37.22%～66.37%, and that of polygene was 5.96%～26.09%. 6. Using BC1F1 as mapping population, a genetic map in rapeseed (Brassica napes L.) was construct by SSR, RAPD and SRAP marker. It was marked 136 molecular polymorphic site, including 67 markers SRAP,48 SSR and 21 RAPD markers. The genetic map contained 20 linkage groups(LG1-LG20). And the genetic distance was totally 1725.00cM. The average distance between two markers was 15.97cM.7. Two QTLs related to seed oil content were identified with the interval mapping of the software QTL Icimapping v2.2. One QTL was located in the region of SSRRa2-E0-EM15ME14 on linkage group LG10, which could explain 4.43% of the oil content variation in the population and additive effect was 0.42%. The other was located in the region of EM5MEllb-EM12ME14 on LG15, and explained 18.68% phenotypic variation and additive effect was -0.60%.Two QTLs related to oleic acid were identified. One QTL was located in the region of EM12ME17-EM9ME10 on linkage group LG15, which could explain 8.99% of the oleic acid content variation in the population and additive effect was 1.58%. The other was located in the region of AG16-EM17ME15b on LG20, and explained 5.30% phenotypic variation and additive effect was -1.22%. One QTL related to linoleic acid were identified. It was located in the region of EM5MEllb-EM12ME14 on linkage group LG15, which could explain 9.46% of the linoleic acid content variation in the population and additive effect was 0.68%.更多还原