老芒麦落粒机理初探及新种质创制

发布时间：2019-01-02 20:56

【摘要】：老芒麦(Elymus sibiricus L.)是一种多年生、冷季型、自花授粉的异源四倍体禾本科牧草,具有适口性好、粗蛋白含量高、适应性强等优良特性。我国老芒麦种质资源丰富,近年来老芒麦被广泛应用于青藏高原及中国北方地区退化草地改良和草地畜牧业发展。然而,老芒麦的落粒性对种子产量造成严重损失,制约着优质老芒麦的推广利用。目前,我国有8个老芒麦育成品种,但落粒依旧是其亟待解决的育种问题之一。为了进一步揭示老芒麦落粒机理并培育低落粒老芒麦优异新种质,本研究在老芒麦资源收集和评价基础上,从离层解剖结构、水解酶活性等方面研究了老芒麦落粒的组织学和生化机理,并利用杂交育种结合分子标记技术创制了老芒麦新种质,为老芒麦低落粒品种选育奠定基础。主要试验结果如下:1.对28份老芒麦种质落粒性和其他14个农艺性状进行观测,并利用隶属函数法对其农艺性状进行综合评价。结果表明:各供试老芒麦种质在盛花期后31d时落粒率显著增加并达最大值,在Zh N02、HZ03和LQ05群体内各单株间落粒率存在较大变异。两年观测数据表明XH09的落粒率最高,其次为XH03、LQ03和LQ04,落粒率最低的种质为Zh N03,MQ01次之。相关分析表明落粒率与旗叶宽和茎节数呈显著负相关,与倒二叶宽呈极显著负相关。其余各观测性状变异性分析表明,分蘖数在所有评价指标中变异性最大,变异系数为17.07%。15个农艺性状聚类结果和隶属函数分析结果均表明,Zh N03在28份种质中综合农艺性状最优。2.分别测定9份老芒麦栽培种和6份野生种质在小花梗断裂时承受的最大拉力即BTS(breaking tensile strength)值,并对其小花梗离区进行组织解剖学和细胞壁水解酶活性变化分析。结果表明:野生种质的落粒性比栽培品种高,其中PI655199平均BTS值最高(144.51 gf),而LQ04最低(47.17 gf);抽穗后14 d离区开始出现降解,高落粒种质离区降解程度高、断裂面表现光滑、离区木质素含量更低;纤维素酶和多聚半乳糖醛酸酶和老芒麦离区水解相关,但在老芒麦不同发育时期,这两种酶活性变化大。3.以在落粒性和其他农艺性状上存在显著差异的老芒麦为亲本进行杂交育种,通过9对EST-SSR分子标记对其F1真实性进行检测,同时对F1群体和亲本群体做群体结构和遗传多样性分析。结果表明:基于杂种和亲本DNA指纹图谱从5个不同的杂交组合中鉴定出15个真实的F1单株;老芒麦亲本和杂交种群体的平均多态性比率为70.51%。
[Abstract]:Laowangmai (Elymus sibiricus L.) It is a perennial, cold-season, self-pollinated allotetraploid gramineous forage with good palatability, high crude protein content and strong adaptability. China is rich in germplasm resources. In recent years Laomangmao has been widely used in the improvement of degraded grassland and the development of grassland animal husbandry in the Qinghai-Tibet Plateau and northern China. However, the seed drop of Agaricum sibiricum has a serious loss on seed yield, which restricts the popularization and utilization of high quality Avena sibiricum. At present, there are 8 varieties in China, but seed dropping is still one of the breeding problems to be solved. In order to further reveal the mechanism of grain falling and to cultivate new germplasm with low grain, this study was based on the collection and evaluation of germplasm resources and anatomical structure of the separated layer. In this paper, the histology and biochemical mechanism of seed dropping in Laowangmai were studied from the aspects of hydrolase activity, and a new germplasm was created by hybrid breeding combined with molecular marker technique, which laid a foundation for the breeding of low grain varieties of Laowangmai. The main results are as follows: 1. The granulation and other 14 agronomic characters of 28 germplasms of Laowangmao were observed and their agronomic characters were evaluated by membership function method. The results showed that the seed dropping rate of the germplasm increased significantly and reached the maximum value at 31 days after full flowering, and there was a great variation in the seed drop rate among the individual plants in the Zh N02 HZ03 and LQ05 populations. The results of two years observation showed that the seed drop rate of XH09 was the highest, and the lowest of XH03,LQ03 and LQ04, was Zh N03 MQ01. Correlation analysis showed that the seed drop rate was significantly negatively correlated with flag leaf width and stem node number, and with the upper second leaf width. The analysis of the other observed traits showed that the number of tillers was the most variable among all the evaluation indexes, and the coefficient of variation was 17.07.15 agronomic characters, and the results of cluster analysis and membership function analysis showed that the number of tillers was the highest in all the evaluation indexes. Zh N03 was the best in 28 germplasm. The maximum tensile force (BTS (breaking tensile strength) of 9 cultivated and 6 wild germplasms with small pedicel breakage was determined, and the tissue anatomy and cell wall hydrolase activity of 9 cultivars and 6 wild germplasm were analyzed. The results showed that the seed dropping ability of wild germplasm was higher than that of cultivated variety, and the average BTS value of PI655199 was the highest (144.51 gf),) and LQ04 was the lowest (47.17 gf);). On the 14th day after heading, degradation began to appear in the isolated area, the degradation degree of the high grain falling germplasm was high, the fracture surface was smooth, and the content of lignin in the isolated area was even lower. The activities of cellulase and polygalacturonase were correlated with the hydrolysis of Laowangmai in vitro, but the activity of these two enzymes varied greatly at different developmental stages. 3. Hybrid breeding was carried out with Laowangmai, which had significant differences in grain setting and other agronomic characters, and its F1 authenticity was detected by 9 pairs of EST-SSR molecular markers. At the same time, the population structure and genetic diversity of F1 population and parent population were analyzed. The results showed that 15 true F1 plants were identified from 5 different cross combinations based on DNA fingerprinting of hybrid and parent, and the average polymorphism ratio of parents and hybrids was 70.51%.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S54

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