【作者】 向勇；

【导师】 傅体华；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2009， 硕士

【摘要】 高产、抗倒伏一直是小麦育种的重要目标性状,而矮秆品种的优点就在于其具有较高的抗倒伏性、良好的肥水反应以及高的收获指数,矮秆已成为世界范围内小麦高产、超高产育种的主要目标性状。但矮秆基因单一化现象十分严重,不断寻找鉴定利用新的矮秆种质资源是克服这一弊端的重要途径。中间偃麦草（Elytrigia intermedium）是禾本科小麦族偃麦草属的优良物种,具有根系发达、再生力强、抗旱、抗寒、耐贫瘠、大穗多花等优良特点,它易与小麦杂交,是偃麦草属中最先与小麦杂交成功,并为小麦育种提供许多有益基因的物种之一。本研究采用形态学、细胞遗传学和原位杂交相结合的方法,对普通小麦与八倍体小偃麦的一个后代矮秆株系08-725进行了鉴定;同时针对矮秆小麦的特性,对其做了与赤霉酸（GA₃）的反应鉴定。实验结果如下:1.株系08-725能够正常的发育和结实,各个单株表现为较为一致的矮化特性,株高明显低于其亲本川麦107,株系中有可能存在一个影响株高的基因。2.细胞学鉴定结果,根尖细胞和花粉母细胞减数分裂中期Ⅰ染色体的数目为2n=42,花粉母细胞减数分裂中期Ⅰ染色体构型2n=20.52Ⅱ+0.27Ⅰ+0.14Ⅲ+0.07Ⅳ,株系08-725基本上趋于稳定。存在少量的单价体、三价体和四价体,并且在花粉母细胞减数分裂后期Ⅰ发现有落后染色体及染色体桥形成。结合根尖染色体的数目与结构分析,可以初步的判断该材料可能属于小麦-中间偃麦草的易位。3.基因组原位杂交结果显示,08-725的42条染色体中有两条染色体的一臂呈现黄绿色（杂交信号）,而另一臂和其余40条呈现红色,未见任何杂交信号。证实08-725通过易位导入了中间偃麦草的片段,而且结合矮杆性状推测,该片段基因可能携带有一个具有很强降秆能力的矮杆因子。4.与赤霉酸反应结果。在幼苗形态上:08-725和农林10号的各个处理与对照之间无显著差异,都表现为矮壮、绿、叶子不发生披垂,披垂型仅仅发生在经过赤霉酸处理的川麦107的幼苗上面。t检验结果表明:08-725经过赤霉酸处理结果与农林10号相类似,第一叶长和胚芽鞘长与对照相比较,相差很小,远远低于显著水平。鉴定结果08-725对赤霉酸反应为不敏感型。更多还原

【Abstract】 The high-yield and lodging resistance have been the important target traits in the wheat breeding.All the lodging resistance,good response to fertilizer and high harvest index are the advantage of the dwarf varieties.The dwarf varieties have been the main target traits in the high-yield wheat and super-high-yield breeding of the wheat.However, the simple phenomenon of the dwarf genes is very serious.The important way to solve this shortcoming is constantly searching for identification of the new dwarf germplasm resources to use.Thinopyrum intermedium,one of species in Thinopyrum of Triticeae, has excellent characteristics,such as drought resistance,cold resistance,tolerance to bad environments,big spike and multi-spikelet.It is easy to cross with wheat,and many desirable genes in Th.intermedium have been transferred into wheat.In this experiment,the morphology,cytogenetics and situ hybridization method were used to identify a wheat dwarf line 08-725 which derived from the progenies of common wheat and Th.intermedium.The reaction of 08-725 with GA3 was also carried out.The results were as follows:1.Line 08-725 could be normal growth and grain.The most important characteristic of the line is far shorter than the height of its wheat parent Chuanmai 107 which inferred that a gene or chromosome fragment could be existed to reduce the plant height in line 08-725.2.The number of chromosomes with root tip of line 08-725 was counted.The results indicated that the chromosome number were 2n = 42.3.The chromosome pairing configuration of line 08-725 was 2n=20.52Ⅱ+0.27Ⅰ+0.14Ⅲ+0.07Ⅳthrough pollen mother cell meiosisⅠchecked.The result demonstrated that line 08-725 might be cytologically stable.However,there were still a small number of univalent,trivalent and quadrivalent,and log chromosomes and chromosomal bridge were also observed in PMC AI Combination of root tip chromosome number and structure analysis,wheat - Thinopyrum intermedium translocation or chromosome structure modification might be occurred in line 08-725. 4.Genomic in situ hybridization results showed that one arm of the 2 chromosomes showed yellow-green（hybridization signal）,while the other arms showed red hybridization signal among the 42 chromosomes.It is apprarently that line 08-725 is a fragment translocation between wheat and E.intermedium chromosomes,and the fragment translocation might be carried one dwarf gene which has strongly reduced the plant height.5.The results of gibberellic acid reaction indicated that the first leaf length and coleoptile length had little difficences,but no significant differences were found in wheat variety Nonglin 10 and line 08-725.However,drooping on leaves of Chuanmai 107 was observed when the seedling of Chuanmai 107 was treated by different GA3 solutions,and significant differenc was recorded by t-test.Those results suggested that gene to reduce plant height in line 08-725 might not be sensitive to the GA₃,and it might be the pleiotropic role of the dwarf gene.更多还原