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为了将四倍体球茎大麦(H.bulbosum)的有用性状导入二倍体栽培大麦(H.rulgare),将二者进行杂交,并通过胚培养技术获得了11个有生活能力的三倍体F_1植株。杂种减数分裂染色体配对中形成三价体的平均频率为1.3/每花粉母细胞,最多为5/每花粉母细胞。三倍体F_1与二倍体亲本大麦回交,获得了9个BC_1植株。其中3株具有H.bulbosum的DNA或抗病性。用Bam HIDNA水解的基因组进行Southern印迹时,种的特异性611-bpDNA探针pSc119.2(位于H.bulbosum染色体组的端粒上)清晰地检测出在BC_1-5植株中有5个H.bulbosum的DNA片段,其长度分别为2.1、2.4、3.4、4.0和4.8kb。通过N-带染色发现BC_1-5植株亦含有染色体3与染色体4的异源染色体交换。用pSc119.2进行原位杂交检测到两条易位染色体之一的端粒区具有H.bulbosum序列。另外两个BC_1植株(BC_1-1和BC_1-2)抗两个白粉病菌系,而栽培大麦亲本对这些菌系则为感染。由BC_1-2所得的79株BC_2中有32株抗病,47株感病,符合1:1的分离比例,表明抗性是由1个显性基因控制的。正反交结果表明,与抗病性有关的配子选择具有倾向性。通过DNA多聚酶链式反应(PCR)以10碱基随机引物对抗白粉病植株BC_1-2加以鉴别时,发现其中亦具有长短为1kb的H.bulbosumDNA片段。从79个BC_2植株中随机取样43株,其中有/无1kb H.bulbosum DNA片段的植株分别为23株和20株,符合1:1的分离比例,表明PCR产物来源于1个单基因位点。对17个抗病植株和17个感病植株各自的混合DNA的PCR分析以及43个单株的特性分离结果,都表明1kb DNA片段及抗病性是彼此独立遗传的。所获后代在作物育种上可供作重要的抗源。
In order to introduce the useful trait of H. bulbbosum into H.rulgare, the two were crossed and the viable triploid F_1 Plant. The average frequency of triad formation in hybrid meiotic chromosome pairing is 1.3 per pollen mother cell, up to 5 per pollen mother cell. Triploid F_1 was backcrossed with diploid parent barley and 9 BC_1 plants were obtained. Three of them had H.bulbosum DNA or disease resistance. When Southern blots were made with the Bam HIDNA-hydrolyzed genome, the species-specific 611-bp DNA probe pSc119.2 (located on the telomere of the H. bulbosum genome) clearly detected 5 H in BC_1-5 plants. The bulbosum DNA fragments were 2.1, 2.4, 3.4, 4.0 and 4.8 kb in length, respectively. It was found by N-band staining that BC1-5 plants also contain heterologous chromosome exchange between chromosome 3 and chromosome 4. In situ hybridization with pSc119.2 detected a telomeric region of one of the two translocations with the H. bulbosum sequence. The other two BC1 plants (BC_1-1 and BC_1-2) were resistant to two powdery mildew strains, whereas cultivated barley parents were infected by these strains. Of the 79 BC2s obtained from BC_1-2, 32 were resistant to disease and 47 were susceptible to the disease, which corresponded to a 1: 1 segregation ratio, indicating that resistance is controlled by a dominant gene. The results of reciprocal cross show that the selection of gametes related to disease resistance has a tendency. When DNA polymerase chain reaction (PCR) was used to identify the powdery mildew plant BC_1-2 with a random primer of 10 bases, it was found that there was also H.bulbosumDNA fragment of 1kb in length. A total of 43 plants were randomly sampled from 79 BC_2 plants. Among them, 23 and 20 plants with / without 1 kb H.bulbosum DNA fragment, respectively, were consistent with the ratio of 1: 1, indicating that the PCR products were derived from one single locus . PCR analysis of the mixed DNA of 17 resistant plants and 17 susceptible plants, and characterization of 43 individual plants, all showed that the 1 kb DNA fragment and disease resistance were inherited independently of each other. The descendants can be used as important source of resistance in crop breeding.