【作者】 蔡进进；

【导师】 孔令让； 王洪刚；

【作者基本信息】 山东农业大学 ， 作物遗传育种， 2011， 硕士

【摘要】 二倍体长穗偃麦草(Thinopyrum elongatum, 2n = 14),六倍体中间偃麦草(Thinopyrum intermedium, 2n = 42)和十倍体长穗偃麦草(Thinopyrum Ponticum, 2n = 70),是偃麦草属中主要的种,蕴含着丰富的优良基因。偃麦草属的7E染色体含有抗赤霉病、抗叶锈病、抗大麦黄矮病等优良基因,是进行小麦遗传改良的宝贵资源。本实验室利用具有不同优良性状特点的小麦-偃麦草异染色体系,通过细胞学、原位杂交和分子标记等方法,对外源染色体7E进行了综合鉴定和亲缘关系分析。获得以下主要研究结果:(1)利用基因组原位杂交(GISH)技术对4个小麦-偃麦草异代换系的基因组构成进行了分析。结果表明,小麦-中间偃麦草异代换系P29和小麦-十倍体长穗偃麦草异代换系(K11463)中的7E染色体供体同为J染色体;小麦-十倍体长穗偃麦草异代换系(K2620)中的7E染色体供体为St染色体;小麦-二倍体长穗偃麦草异代换系(7E/7D)中的7E染色体供体为Ea。(2)利用卡方检验,发现十倍体长穗偃麦草7E染色体图谱中有44个分子标记表现为偏分离,占总标记位点数的68.75%;并且,这些偏分离标记形成3个偏分离热区。但是,偏分离区域并不包含抗赤霉病和抗叶锈病基因连锁标记。这表明:7E染色体图谱具有准确性和可靠性;在分子标记辅助育种中,与抗赤霉病和抗叶锈病基因连锁的标记可被有效的利用。中间偃麦草的7E特异分子标记(32个)有4个与十倍体长穗偃麦草7E图谱上标记(64个)相同,说明它们之间有一定的亲缘关系。(3)结合原位杂交结果,普通细胞学镜检研究表明:K2620中含有的十倍体长穗偃麦草St染色体和异代换系7E/7D中的二倍体长穗偃麦草的Ea染色体的配对率达22%,说明St和Ea染色体具有部分同源关系。但是,K2620所携带的十倍体长穗偃麦草的St染色体和P29含有的中间偃麦草J染色体的配对率仅为5%,说明二者之间的亲缘关系较远。同样,K11463中含有的十倍体长穗偃麦草的J染色体和7E/7D中二倍体长穗偃麦草的Ea染色体的配对率为8%,说明其亲缘关系也较远。更多还原

【Abstract】 Species of Thinopyrum, including Th. intermedium, Th. elongatum and Th. Ponticum, posses a number of elite agronomic traits, and thus all of the three have been the most important perennial Triticeae germplasm sources for further wheat improvement. Chromosome 7E of Thinopyrum is crucial because it is the carrier of a number of genes including fusarium resistance, leaf rust resistance, stem rust resistance, and yellow dwarf virus resistance. In the present study, their homeologous relationship among different Thinopyrum chromosome 7E were identified and analyzed by methods of morphology, cytology and molecular biology. The main results were as follows:(1) Genomic in situ hybridization (GISH) was used to establish the genomic origins of the 4 alien chromosomes in substituted lines. Two substituted lines, P29 and K11463, had a pair of J-genome chromosomes. A pair of St chromosomes were detected in K2620. A pair of Ea chromosomes substituted a pair of wheat chromosomes in 7E/7D derived from Th. elongatum.(2) The segregation ratio of 64 molecular markers was investigated on the Th.ponticum chromosome 7E. Among them, 44 showed significant segregation distortion (P<0.05), and the preferential segregation pattern was in favor of chromosome K2620, which was derived from the male parent K2620. The distorted markers on the map of chromosome 7E were clustered as segregation distortion regions (SDR). However, such a segregation distortion pattern was not observed within the regions harboring the Lr19 and FhbLoP genes, suggesting that these closely-linked markers could be valuable for marker-assisted introgression of elite genes into our existing wheat cultivars.(3) Meiotic paring was also studied in 3 hybrid progenies. Since pairing between P29 with K2620 and 7E/7D chromosomes was generally low, it is suggested that the chromsomes are not closely related. By methods of GISH and cytology, K2620 and 7E/7D chromosomes are related homeologously.更多还原