【作者】 万成燕；

【导师】 牛应泽；

【作者基本信息】 四川农业大学 ， 生物化学与分子生物学， 2011， 硕士

【摘要】 油菜是世界上非常重要的油料作物之一,也是我国食用植物油的主要来源。经过改革开放后几十年的努力,我国油菜种植面积不断扩大、单位面积产量不断增加,已成为国际上最大的油菜生产国。然而,目前我国油菜平均含油量却只有40%,比进口油菜籽的含油量低了三至五个百分点,与此同时,我国现在以及今后很长一段时间里对油料作物的需求很大,需要从国外进口大量油料作物才能满足缺口。因此提高我国油菜籽的含油量显得极为重要和迫切。本研究构建了甘蓝型油菜高含油量品系CG38(P1)与低含油量品系B25(P2)杂交的六个世代Pl、P2、Fl、B1、B2和F2,利用数量性状的主基因+多基因联合分离分析法对油菜含油量性状进行了遗传分析。另外以BCl为作图群体,综合利用了SSR、RAPD和SRAP三种分子标记构建了一张分子标记遗传图谱,同时利用QTL Icimapping v2.2完美区间分析法对含油量进行QTL定位。主要研究结果如下：1、经NIR Systems-5000型近红外分析仪对六个世代的含油量测定得知,高含油量亲本CG38的平均含油量为41.67%,低含油量亲本B25(P2)的平均含油量为30.02%,相差11.65%,双亲在含油量性状上表现为差异极显著。Fl的含油量平均为37.04%,介于双亲之间,同时高于中亲值35.85%,偏向高含油量亲本P1,说明高含油量对低含油量有部分显性；三个分离世代BI、B2、F2的含油量均呈现连续性分布,其中BI的含油量的平均值高于B2,说明控制油菜含油量的基因受加性效应的影响,各世代中都没有表现出超亲现象。2、利用植物数量性状主基因+多基因遗传模型多世代联合分析法对CG38×B25的六个世代含油量的分析表明,油菜含油量的最佳遗传模型为D-0模型,即含油量受1对加性-显性主基因+加性-显性-上位性多基因遗传控制,广义遗传率为62.55%-94.38%,平均为75.84%；而环境变异占表型变异的5.62%-37.45%,平均为24.16%；由此可见,油菜含油量同时受到了来自基因型和环境两方面的影响。该组合中,主基因遗传力为25.81%～67.26%,平均为46.04%；多基因遗传力为27.12%～44.77%,平均为29.79%,其中B1和F2的主基因遗传力较大,分别为45.06%和67.26%,多基因遗传力较小,分别为17.49%和27.12%,而B2以多基因遗传为主。表明含油量的遗传由主基因和多基因共同控制,受主基因遗传为主。3、以BC1群体的218个单株为作图群体,选用SSR、RAPD和SRAP三种分子标记构建了一张甘蓝型油菜分子标记遗传连锁图谱。图谱包含20个连锁群,136个标记位点,其中有67个SRAP标记位点,48个SSR标记位点和21个RAPD位点。图谱全长1725.00cM,标记间平均距离为15.97cM。4、利用QTL分析软件QTL Icimapping v2.2对甘蓝型油菜的含油量性状进行了QTL定位分析,共检测到了2个与含油量相关的QTL位点,其中qOC1位于连锁群LG10的SSRRa2-E03～EM15ME14标记区间,可解释含油量的表型变异的4.43%,加性效应为正值,表明其作用方向为增加含油量；qOC2位于连锁群LG15的EM5ME11b～EM12ME14标记区间,可解释含油量的表型变异的18.68%,加性效应为负值,表明其作用方向为减少含油量。5、综合以上分析结果可以看到,油菜含油量的遗传力较高,因此,在育种过程中,通过早期世代对高含油量性状进行选择是有效的。同时本实验中,含油量受主基因+多基因遗传控制,主基因遗传力平均为46.04%,加性效应为2.3120,表明高油亲本对含油量具有增效作用；B1、B2和F23个分离世代的含油量都高于低含油量亲本,而且B1的平均含油量38.61%明显高于B2的34.46%,说明高含油量育种应首先考虑利用高含油量主基因的效应。因此,在油菜高含油量育种中,我们应该选用高油量亲本,采用杂交或轮回选择等常规育种手段,同时结合QTL定位的方法找到与主基因相连锁的分子标记来提高增效基因频率来改良提高含油量性状。更多还原

【Abstract】 Oilseed rape is one of the most important oil crops in the world. It’s also a main source of edible oils in China. After several decades of hard work, rapeseed area in China has been significantly expanded, and the unit area yield markedly increased. China has been largest rapeseed producer in the word. However, rapeseed in our contry was lower in oil content than the imported. In our contry, the average oil content in rapeseed was about 40%, while the imported rapesed contains an oil content of up to 43%-45%. At the same time, with China’s growing demand for vegetable oils, we need to import large quantities of oil seeds or vegetable oils to meet the gap for a long time. So, it is very important to increase the oil content in the rapeseed in our contry. In this study, the genetic models of oil content in rapeseed (Brassica napus L.) were analysized with six genetic populations (P1, P2, F1, B1, B2 and F2) of the cross CG38 (high oil content)×B25 (low oil content) by a mixed genetic model of major gene plus polygenes. In addition, using BC1 as amapping population, SSR、RAPD and SRAP were used to construct a molecular linkage map. Finally, we used QTL Icimapping v2.2 to identificate the QTL of oil content. The main results from the research were as follows:1. NIR Systems-5000 was used to test the six generations’oil content. The results showed that the average oil content of high oil content parent CG38 was 41.67%, and low oil content parent B25 was 30.02%, they have a difference of 11.65%, and showed significant difference in the traits of oil content. The oil content of F1 was 37.04% for average, it’s higher than P2, lower than P1, and it’s even higher that the midparent value 35.85%, skewed towards the high oil content parents P1. From that, we can see high oil content has some dominance effects with low oil content. Three separate generations of B1, B2, F2 showed a continuous distribution of the oil content, the mean of oil content in B1 was higher that that in B2.which indicated that the gene which controled the oil content have additive effects. In this research, none of the six generations showed the phenomenon of surplus.2. The genetic models of oil content in rapeseed (Brassica napus L.) were analysized with six genetic populations (P1, P2, F1,B1, B2 and F2)of the cross CG38XB25 by a mixed genetic model of major gene plus polygenes. The results showed that oil content in Brassica napus L. was controlled by one pair of additive-dominant major gene plus additive-dominant-epistatic polygenes (D-0). The genetic and environmental variances accounted for 75.84% and 24.16% of the phenotypic variance, respectively. It was indicated that both genetic and environmental factors played important roles in oil content in Brassica napus L. On an average, the inheritabilities of major gene and polygenes were 46.04% and 29.79%, respectively. It was demonstrated that oil content in Brassica napus L. was controled by both major gene and polygenes, and that the major gene played a greater role.3. In this study,218 plants from BC1 were used as a mapping population, and three kinds of molecular markers SSR、RAPD and SRAP were used to construct a genetic linkage map of Brassica napus L.. This genetic linkage map contained 20 linkage groups,136 marker loci including 67 SRAP,48 SSR and 21 RAPD loci. The total length of the genetic linkage map was 1725.00 cM, and the average distance between markers was 15.97cM.4. The QTL’s of oil content in Brassica napus L. were analyzed by QTL Icimapping v2.2. In the experimental materials, we identified two QTLs associated with oil content. qOCl was located on linkage group LG10, and the marker interval was SSRRa2-E03～EM15ME14. qOCl could explain 4.43% of the phenotypic variation of oil content Brassica napus L.. And the positive additive effect indicated qOC1 could increase the oil content. qOC2 was located on linkage group LG15, and the marker interval was EM5ME11b～EM12ME14. qOC2 could explain 18.68% of the phenotypic variation of oil content Brassica napus L.. And the negative additive effect indicated qOC2 could reduce the oil content.5. Genetic analysis showed a high heritability of oil content in rapeseed, so, in the breeding process, the high oil content traits selection in early generation was effective. And in this study, oil content was controlled by the major gene plus polygenes, the heritability of the major gene was 46.04% by average, additive effect was 2.3120, indicated that the parent of high oil content have a synergistic effect on the oil content. The oil content of B1, B2 and F2 were higher than the low oil content parent, and the mean of oil content of Bl(38.61%)was higher than that of B2(34.46), so during the high oil content breeding, the use of the major gene effect should be first considered. Therefore, in high oil content breeding, we should choose high oil content parents, and take the conventional breeding methods of hybrid and recurrent selection, combined with the methods of QTL localization to increase the frequency of allele to improve oil content trait in oil rape.更多还原