【作者】 李丹；

【导师】 万怡震；

【作者基本信息】 西北农林科技大学 ， 果树学， 2008， 硕士

【摘要】 2005年至2007年以石榴15个类型共73个品种为试材,利用9个枝叶性状、9个果实品质性状、裂果抗性、干腐病抗性、216个AFLP分子标记进行了遗传多样性分析和聚类分析,并利用果实品质性状和抗性性状对石榴品种资源进行了综合评价与优良品系筛选,主要研究结果如下:通过对石榴品种抗裂果性能的综合评价认为,不同石榴品种间抗裂果性能差异显著,选育不裂果和抗裂果品种是解决石榴裂果这一生产问题的有效途径之一。在本次试验的60个品种中,不裂果、抗裂果、轻度裂果、中度裂果和严重裂果品种个数分别为2个(占0.03%)、13个(占21.67%)、41个(占68.33%)、3个(占6.7%)、1个(占1.67%).石榴品种间干腐病抗性表现差异极显著。其中,高抗、抗病、感病和高感品种个数分别为4个(占5.49%)、29个(占39.74%)、37个(占50.69%)、3个(占4.11%)。石榴品种抗裂果性能和干腐病抗性的相关性不显著。‘三白甜’和‘天红蛋’两个石榴类型的裂果抗性与干腐病抗性表现为显著或极显著相关。因此,石榴抗病基因遗传背景复杂。对8个果实品质性状共进行28对相关性分析,结果表明,12对(41.86%)性状相关系数表现出显著或极显著相关。果型指数(纵径/横径)越大,果皮越薄,百粒重越大,果实可溶性糖、Vc含量越高,总酸含量越低,核硬度越软。因此,在生产中选择果型指数大(果型高桩),果皮薄,可溶性糖与Vc含量高,总酸含量低,核软等综合品质性状优良的石榴品种是切实可行的。通过对12个类型共67个品种8个果实品质性状的主成分分析,提出了石榴优种选择的5个重要主成分,这5个主成分代表了供试性状82.38%的综合信息。因此,应用此方法中的主成分作为石榴优种选择标准,较应用单一性状加权打分选择相比,可最大化的降低性状间的相关性对选择效果的影响,具有更高的准确性和科学性。通过综合分析各石榴品种的性状指标选择优质、抗裂、抗病优良品种,我们认为,‘净皮甜’类型中的‘临研23号’以及‘大红酸’类型(‘临研29号’、‘临研38号’)表现出优质、抗裂、抗病等综合优良性状,建议在生产中推广利用。从形态指标及抗性指标来看,石榴各品种在枝叶形态、果实品质、裂果抗性和干腐病抗性指标上均表现出了丰富的多样性。通过AFLP分子标记分析发现,平均多态性位点百分率为54.28%,表现出较高的多样性。通过枝叶形态指标、果实品质指标聚类分析来看,这些指标的聚类结果与生产上的品系归类不尽一致。分子水平的亲缘关系分析与采用形态指标进行的亲缘关系分析结果也有很大出入。本研究利用AFLP获得的分子亲缘关系图谱为石榴杂交亲本选配提供了理论依据。更多还原

【Abstract】 The genetic diversity analysis and cluster analysis were performed in 73 varieties of 15 types of pomegranate from 2005 to 2007, using 9 branch-leaf traits, 9 fruit quality traits, resistance to fruit cracking, resistance to dry rot as morphological markers, and 216 AFLP molecular markers. Fruit quality traits and resistance to fruit cracking, resistance to dry rot traits in pomegranate resources were used to comprehensively evaluate and to screen the superior cultivars for extension.The variance analysis of resistance to fruit cracking showed that the variance was significant among cultivars. To select the cultivars with highly resistance to fruit cracking was one of the efficient ways to decrease the fruit cracking seriously arising in the production. Among the 60 cultivars, the cultivars of immunity (CI = 0), of high resistance (CI = 0.1-5.0), of resistance (CI = 5.1-25.0), of susceptibility (CI = 25.1-50.0), and of high susceptibility (CI = 50.1-100.0) to fruit cracking, were 2 (0.03%), 13 (21.67%), 41 (68.33%), 3 (6.7%) and1 (1.67%), respectively.The variance analysis of resistance to dry rot showed that the variance was also significant among cultivars. Among them, the cultivars of immunity (CI = 0), of high resistance (CI = 0.1-5.0), of resistance (CI = 5.1-25.0), of susceptibility (CI = 25.1-50.0), and of high susceptibility (CI = 50.1-100.0) to dry rot, were 4 (5.49%), 29 (39.74%), 37 (50.69%) and 3 (4.11%), respectively.The analysis of correlation coefficient (r) of resistance between the fruit cracking and the dry rot in pomegranates showed that the r-value of all cultivars was insignificant, but the r-value of the cultivars in two types of‘Sanbaitian’and‘Tianhongdan’was significant or extremely significant, which indicates that resistance to two disease is complex.The analysis of 28 correlation coefficients (r) between 8 fruit quality traits showed that the 12 r-values (41.86%), between the traits of the fruit shape indexes (the ratio of vertical diameter to transverse diameter), the fruit skin thickness, the weights of 100 seeds, the soluble solid contents, Vc contents, total acidic acid contents in seed skin, and the hardness of the seed, were significant or extremely significant. Therefore, it is practicable to select the cultivars with the multiple superior traits for extension as the high fruit shape index, thin pericarp, the high contents of soluble solid and Vc, the low total acid contents, and the soft seeds.Principal components analysis (PCA) of 8 fruit quality traits in the 67 cultivars of 12 types showed that the five principal components were proposed for the superior variety selection in pomegranates, which contains 82.38% information of the eight traits. Therefore, these five principal components may be more accurate than the weighed scores from a few traits for the selection and breeding because PCA can minimize the effects of the correlation coefficients between the traits on the selection.After a comprehensive evaluation of 8 fruit traits, resistance to fruit cracking and to dry rot,‘Linyan-23’of the type‘Jingpitian’, and‘Linyan-29’and‘Linyan-38’of the type‘Dahongsuan’, exhibiting high fruit quality and high resistance, were suggested for extension in the pomegranate production.Diversity analysis using morphological traits as traits in leaves, branches, and fruits showed they presented highly polymorphism in pomegranate cultivars. Molecular diversity analysis showed that 54.28% AFLP loci exhibited high polymorphism.The grouping results of the cluster analysis using morphological traits in branches, leaves, and fruits, were inconsistent with those of the classification for the cultivar types used in the production. The clustering results using molecular markers were also much different as those using morphological traits. The cluster analysis using AFLP markers provided a theoretic base and a guide for the parent choosing and mating in the pomegranate breeding.更多还原