【作者】 祁玉洁；

【导师】 戚存扣；

【作者基本信息】 南京农业大学 ， 作物遗传育种， 2011， 硕士

【摘要】 植物远缘杂交是作物遗传改良的重要途径。埃塞俄比亚芥具有黄种皮、抗裂角、抗干旱等优异性状,通过远缘杂交将埃芥的优异农艺性状基因导入到甘蓝型油菜中,选育出黄种皮、抗逆性强的甘蓝型油菜品种是油菜育种研究的热点课题。本研究在已获得的甘蓝型油菜与埃塞俄比亚芥远缘杂种衍生后代多体附加系材料“Nj08-063”的基础上,通过细胞学方法、GISH技术和Southern blot等技术,对其进行细胞遗传和分子遗传学的研究,探究其基因组结构、组成及其与农艺、品质性状的关系,并筛选鉴定甘蓝型油菜附加系材料,为油菜重要农艺性状的基因定位、性状转移和种质创新提供基础材料。主要研究结果如下：1.植株形态观察和农艺性状考察：连续两个世代对Nj08-063植株的形态观察结果,群体单株间植株形态变异较大, Nj08-063群体中72.73%的植株矮化、分枝数差异大、某些植株花粉生活力差(最低39.92%-53.82%)、自交结实率低。群体单株种子间种皮颜色分离明显,有褐色、黄褐色、黄色种子;芥酸含量变异较大(0.47%-40.16%)。2.细胞学观察结果：Nj08-063植株和Nj08-063种子根尖细胞染色体数分别在2n=34-44和2n=34-41均有分布；根尖细胞染色体平均数为2n=37.66±2.56和37.68±±2.36。减数分裂中期Ⅰ(MI)染色体基本构型为(0-4)Ⅰ+(16-23)Ⅱ+(0-2)Ⅲ和(0-8)Ⅰ+(14-24)Ⅱ+(0-4)Ⅲ+(0-1)Ⅳ;此外,还观察到大量单价染色体(21.83%)、染色体桥(1.45%)、染色体落后(4.84%)、染色体分裂周期不同步(0.39%)及不均等分离(44.04%)等现象。表明Nj08-063是甘蓝型油菜多体附加系,在甘蓝型油菜基础染色体上附加了多条额外染色体。3. GISH、PCR和Southern blot分析：利用GISH、PCR和Southern blot技术对Nj08-063群体中形态特异、染色体数目异常(2n>38)的植株进行染色体组成分析。基因组原位杂交结果表明,在”Nj08-063”衍生后代群体植株染色体上未检测到明显的B组染色体杂交信号；采用Southern blot分析结果表明,杂交信号仅出现在含有芸薹属B组染色体的黑芥和埃塞俄比亚芥上,而在甘蓝型油菜和”Nj08-063”衍生后代群体中并未无杂交信号,表明”Nj08-063"植株中不含有B组染色体着丝粒区域特异性的重复序列。4.上述结果表明,虽然Nj08-063植株性状、种皮颜色和品质性状中携带’’Dodolla"的性状,并在基础染色体上附加了多条染色体,但原位杂交和分子生物学检测结果均表明”Nj08-063”附加染色体中可能不含有整条B组染色体。其附加的染色体可能源自基础染色体的复制,所获得的非整倍体材料可能是种内非整倍体。该结论有待进一步研究证明。更多还原

【Abstract】 Distant hybridization is an important approach for crop genetic improvements. Brassica carinata is characterized by several desirable agronomic characteristics, such as yellow seed-coat color, reducing pod shattering and tolerant to drought stress. Therefore transfer these positive traits to B. napus by distant hybridization is becoming more and more important on rapeseed breeding. The progenies of "Nj08-063", which derived from an inter-specific cross of Brassica napus and B. carinata, were studied by cytological genetic observation, GISH and Southern blot, in order to learn about the structure and composition of the genome and the relationship with the agronomical traits. The new germplasm created in this study could be used in rapeseed breeding and some other researches. Main results are as follows:1. Morphology and agronomic traits in the progenies of "Nj08-063":Morphology variations in progenies of "Nj08-063" were observed,72.73% plants were shorter than their parents; some of them had low fertility and resulting no or little seeds. The seed-coat color of the progenies of "Nj08-063" were various, include yellow, brown and black, and the erucic acid content in this population were ranged from 0.47% to 40.16%.2. The results of cytological genetic observation:The chromosome number in the populations of "Nj08-063" and progenies ranged from 2n=34 to 44 and 2n=34 to 41, and the average numbers were 37.66±2.56 and 37.68±2.36, respectively. The base chromosome configuration were (0-4)Ⅰ+(16-23)Ⅱ+(0-2)Ⅲand (0-8)Ⅰ+(14-24)Ⅱ+(0-4)111+(0-1)IV at the meiotic metaphaseⅠ. Abnormal chromosome behaviors such as univalent (21.83%) chromosome bridges(1.45%), lagging chromosomes(4.84%), meiotic cycle asynchrony (0.39%). chromosome unequal distribution at meiosis stage were often observed in the populations of Nj08-063. The Studying on the number chromosomes in "Nj08-063" showed that "Nj08-063" had more than 38 chromosomes, and were confirmed as multisomic addition line.3. GISH and Southern blot analyses:The results of GISH show that no bright signals were covered with B. nigra probe on the chromosomes of the progenies of "Nj08-063" Southern blot showed that the signal appeared on B. carinata and B. nigra, and no signal appeared on the B. napus and the progenies of "Nj08-063". These results indicated that no B genome specific sequence which localized in the centromeric region of each B genome chromosome was detected in the progenies of "Nj08-063".The results of above showed that the progenies of "Nj08-063" with some traits, such as agronomic traits, yellow-seeded and the higher levels of erucic acids, from B. carinata "dodolla’. Study on GISH and molecule identification in progenies of "Nj08-063" shows that there may be not have the entire B-genome in the progenies of the "Nj08-063". The progenies of "Nj08-063" had more than 38 chromosomes, suggested that the extra chromosome beyond the normal B. napus derived from the duplication of the genome of A and/or C. Further studies are needed to be done to confirm the result.更多还原