【作者】 杨旺兴；

【导师】 祁建民； 许旭明；

【作者基本信息】 福建农林大学 ， 生物工程， 2010， 硕士

【摘要】 水稻籼、粳两个亚种间的遗传距离较大,其杂交后代有着较大的变异和显著的超亲优势,充分利用亚种间或亚种内不同生态型间的杂种优势已成为当今育种的主要途径之一。对水稻籼粳亚种进行多样性及杂种优势分析研究,对合理利用亚种间杂种优势具有重要的理论与实践意义。本研究以39份籼粳衍生系和17份籼、粳稻亲本为材料,采用表型性状和SSR分子标记两种聚类分析方法,对试验材料进行类群划分、比较研究和遗传多样性分析,探讨水稻籼粳亚种的遗传多样性及其籼粳分类属性。同时,选取其中12个有代表性籼粳交材料与8个生产上应用广泛的两系、三系不育系配组,利用SSR标记分析亲本间的遗传多样性与亲缘关系,计算所配组合亲本间的遗传距离,进而分析遗传距离与其杂种优势表现之间的相关性。以期为育种亲本的选择,减少配组的盲目性,提高籼粳交杂种优势利用的有效性,以及改善杂交水稻育种工作效率等方面提供借鉴意义。主要研究结果如下：1、表型聚类分析结果表明,尽管该聚类不能准确反映所有材料之间的亲缘关系,但能准确揭示亲本材料间在形态上的差异,并较准确的将优势类群聚在一起,对于研究不同材料的杂种优势配组具有重要参考价值。试验中发现,表型聚类的第3类群为优势类群,可以重点把握并进行广泛配组,其第1亚群为籼型和偏籼型亲本材料,它们一般有较好的配合力,选用不育系配组均能产生优势组合；其第2亚群为籼粳中间型材料,既具有一般籼稻特征,又有一定粳稻特性,有较好的特殊配合力,选用分蘖力较好、株型较矮、亲和力较好的籼型、粳型不育系配组,更容易出现强优势组合。2、SSR分子标记聚类分析结果表明,该聚类分类结果与表型聚类结果较吻合,通过查阅供试材料系谱,比较分子聚类结果,可以看出它能从分子水平上反映各品种间的差异,并能较准确地了解供试材料的亲缘关系,说明SSR分子聚类可以用于未知材料亲缘关系以及优势类群的划分。3、SSR分子标记遗传多样性分析表明,在Nei基因多样性指数、Shannon多样性指数及多态信息含量指数(PIC)方面,籼粳交品系最大值均大于亲本,其Nei基因多样性指数最大值为0.819,亲本为0.796；籼粳交品系Shannon多样性指数最大值为1.856,亲本为1.677；籼粳交品系多态信息含量(PIC)最大值为0.796,亲本为0.766；说明经过多年世代更替选择,籼粳交品系存在比亲本更丰富的等位基因变异。4、本研究提出两种DNA水平上籼粳分类的划分标准：①85%分类标准：粳(85%-100%)、偏粳(50%-85%)、偏籼(15%-50%)、籼(0%-15%)。②70%分类标准：粳(70%-100%)、偏粳(30%-70%)、偏籼(15%-30%)、籼(0%-15%)。从试验分析可以看出,两种分子标记分类方法与程式分类法相关性均表现显著,85%分类标准与程氏形态指数分类方法极显著相关(r=0.96**),70%分类标准与程式形态指数分类方法显著相关(r=0.89*),说明两种分子标记分类方法均能有效划分品种的籼粳分类,相对于后者,前者更适合。从亲本与籼粳交品系角度来分析,85%分类标准在亲本及籼粳交品系分类上均小于70%分类标准(与形态指数分类相比),亲本不一致性分别为5.88%、11.76%,籼粳交品系不一致性分别为20.51%、25.64%。可以看出籼粳交品系的形态分类与DNA分类不一致性明显高于亲本的；同时,籼粳交品系的形态指数总积分与粳稻的基因频率相关程度(r=0.65**)低于亲本的形态指数总积分与粳稻的基因频率相关程度(r=0.89**),再次验证了判断籼粳交品系分类的复杂性,说明籼粳交品系的籼粳地位较难确定,它们大部分为中间型,介于籼稻与粳稻之间,其兼具有籼稻与粳稻的特征特性。因此,笔者认为,在籼粳交品系分类上,应以形态指数分类为主,分子标记分类为辅；在籼稻或粳稻分类上,应以分子标记分类为主,形态指数分类为辅。5、籼粳交品系配组的杂种优势分析表明,明恢系列籼粳交品系具有以下特点：株高为明显的正向优势,变异幅度较小,96个组合中仅1个组合表现为负向优势；穗长表现为正向超亲优势,变异幅度较小；千粒重表现为一定的正向中亲优势,变异幅度也不大；每穗实粒数和结实率表现出较强的正向优势,籼粳亚种杂交后代结实率低下的难题已基本克服,但其变幅均相对较大,说明明恢系列籼粳交品系杂种后代间表现还是有一定的差异；有效穗数表现为负向中亲优势,说明籼粳交品系杂种F1在分蘖方面相对较弱,有待提高。可以看出,虽然明恢系列籼粳交品系杂种F,在有效穗数、每穗实粒数和千粒重间表现相对不平衡,个别主要产量性状要素正向杂种优势不明显,但由于配组父母本亲本之间性状互补,因而所选组合也表现出较强的产量优势。6、分子遗传距离与杂种优势分析结果表明,96个组合在0.2547-0.5660遗传距离范围内,遗传距离对F1结实率、千粒重的杂种优势影响很小,可以忽略不计,对有效穗数的杂种优势有一定影响,也未达到显著水平,且相关系数很小(r=011,r=0.14),但在株高、穗长、每穗总粒数、每穗实粒数、单株产量等方面,株高中亲优势与超亲优势与遗传距离表现出极显著相关(r=0.44**、r=0.45**),穗长中亲优势与超亲优势与遗传距离呈极显著正相关(r=0.39**、r=0.29**),每穗总粒数中亲优势与超亲优势与遗传距离呈极显著正相关(r=0.30**、r=0.32**),每穗实粒数中亲优势与遗传距离呈显著相关(r=0.23*),超亲优势与遗传极显著正相关(r=0.37**),单株产量中亲优势与遗传距离呈显著相关(r=0.23*),超亲优势与遗传极显著正相关(r=0.34**)。由此可以说明,在0.2547-0.5660遗传范围内,遗传距离能反映单株产量大小,并且,在保证大田亩有效穗数,结实不受低温或恶劣条件影响,下,可以利用SSR标记分析亲本遗传距离进行杂种优势预测。更多还原

【Abstract】 The genetic distance of indica and japonica subspecies of rice is larger, and the progenies of inter-subspecies hybrid have great genetic variation and transgressive heterosis. So to make full use of the different ecotype heterosis in inter-and intra-subspecies has been to become one of the main ways in hybrid rice breeding today. Study on analysis of diversity and heterosis is of important theoretical and practical significance for rational utilization of the heterosis between rice subspecies.Therefore, with 39 derivative lines of indica-japonica hybrid rice and 17 indica and japonica parents as materials, the heterotic grouping, the comparative study and the genetic diversity analysis were researched, and the genetic diversity and indica-japonica categorical attributes of indica and japonica subspecies of rice were also discussed in this paper, by the cluster analysis of phenotypic traits and SSR molecular markers.Meanwhile, using 12 representative rice of indica-japonica cross and 8 widely applied two-and three-line male sterile in production as parents, hybrid rice combinations were established and the genetic distance was calculated by the molecular genetic diversity analyzed by SSR molecular markers, then the correlation between the genetic distance and their heterosis performance was analyzed. The aim was to provide reference meaning for parent selection in breeding, reducing blindness of combining, improving validity of the heterosis of indica-japonica cross, enhancing the work efficiency in hybrid rice breeding and so on several aspects. The main results were as follows:1、The results showed that, though the cluster analysis of phenotypic traits failed to accurately reflect the relationship among the materials, it could more accurately reveal the phenotypic differences and cluster dominant groups. It was of important reference value for the combination of heterosis in different materials. In this test, we found that the third group was the dominant group in the cluster of phenotypic traits, and should be emphatically studied and extensively combined in breeding. The first subgroup in the third group was indica and indica-clinous rice and had good combining ability. The heterosis combinations could be established using the sterile lines and the first subgroup as parents. The second subgroup in the third group was intermediate type of indica-japonica rice and had the characteristics of indica and japonica rice, good combining ability. The strong heterotic combinations could be easily established using the sterile lines of good tillering ability, dwarf plant type, good compatibility and the second subgroup as parents.2、And the results showed that, the result of the cluster analysis of SSR molecular markers was similar with the one of the cluster analysis of phenotypic traits. The differences could be reflected among the strain at the molecular level, and the relationship could be more accurately revealed among the materials, by comparing of the result of the molecular cluster with the pedigree of the test materials. It showed that the cluster analysis of SSR molecular markers could be used to group for the relationship and the heterotic for unknown materials.3、The results showed that, the maximum values of Nei gene diversity index, Shannon diversity index and polymorphism information content (PIC) of strain of indica-japonica cross were all more than the parents’values. The maximum value of Nei gene diversity index of strain of indica-japonica cross was 0.819 and the one of their parents’was 0.796. The maximum value of Shannon diversity index of strain of indica-japonica cross was 1.856 and the one of their parents’ was 1.677. The maximum value of polymorphism information content (PIC) of strain of indica-japonica cross was 0.796 and the one of their parents’was 0.766. It indicated that, there was more abundant allelic variations in strain of indica-japonica cross than that of their parents by generation selection of many years.4、Two division standards were proposed to classify indica and japonica rice in DNA level in this paper. The classification method of standard of 85% DNA japonica components, mainly divided strain of indica-japonica cross into four groups:japonica rice (85%-100%), japonica-clinous rice (50%-85%), indica-clinous rice (15%-50%) and indica rice (0%-15%). And the classification method of standard of 70% DNA japonica components, mainly divided strain of indica-japonica cross into four groups:japonica rice (70%-100%), japonica-clinous rice (30%-70%), indica-clinous rice (15%-30%) and indica rice (0%-15%).From the experimental analysis we could see that the correlations of the two classification methods’and Cheng’s classification method’s displayed remarkably. The highly significant correlation between the classification method of standard of 85% DNA japonica components and Cheng’s morphological classification method (r=0.96**) was observed. And the significant correlation were found between the classification method of standard of 70% DNA japonica components and Cheng’s morphological classification method (r=0.89*). It indicated that, the two classification methods effectively classified strain of indica-japonica cross, and compared with the latter, the former was more suitable for classifying. Starting from the angle of the parents and the strain of indica-japonica cross, the inconsistency values of the classification method of standard of 85% DNA japonica components were all less than the one of the classification method of standard of 70% DNA japonica components as compared with the morphological classification method. The inconsistency values of the parents were 5.88% and 11.76% respectively, and the one of the strain of indica-japonica cross were 20.51% and 25.64% respectively.The inconsistency values of the two methods, the morphological classification method and the classification method of DNA molecular markers, for classifying strain of indica-japonica cross was obviously higher than that of the parents. At the same time, the total score of the morphological index of the strain of indica-japonica cross was lower than that of the parents, and the correlation degree of gene frequency for japonica (r=0.65**) was lower than that of the parents (r=0.89**). It verified complexity of classification of strain of indica-japonica cross again. For strain of indica-japonica cross, it was comparatively difficult in determining the position of indica and japonica because most of strain of indica-japonica cross were intermediate type, lay between indica and japonica, and possessed characteristics of indica and japonica.So it is considered that, for strain of indica-japonica cross, it should be advocated the dominant role of the classification method of the morphological index and the subsidiary role of the classification method of the molecular markers, and in the meantime for indica and japonica, it should be advocated the dominant role of the classification method of the molecular markers and the subsidiary role of the classification method of the morphological index.5、The analysis of heterosis for combinations of strain of indica-japonica cross showed that, the characteristics of MingHui series strain of indica-japonica cross were as follows:The plant height showed obvious positive heterosis with less variation range, only 1 combination expressed negative heterosis in the 96 combinations. The panicle length showed positive transgressive heterosis with less variation range. The 1000-grain weight showed positive mid-parent heterosis with little variation range. The grain number per panicle and the seed setting rate showed positive heterosis with relatively larger variation range, and the problem of the low seed setting rate for the progenies of inter-subspecies cross basically overcome. Certain-difference existed in the progenies of inter-subspecies cross in the MingHui series stains. The effective panicle number showed negative mid-parent heterosis, and this showed that the tillering ability was relatively weaker in the Fl progenies of inter-subspecies cross and should be improved.lt could be seen that, the unbalance existed in the effective panicle number, the grain number per panicle and the 1000-grain weight in the F1 progenies of inter-subspecies cross in the MingHui series stains, and individual main yield characters showed no obvious positive heterosis, but there were strong yield heterosis in the the choised combinations because complementarity of characters existed in their parents.6、The results of analysis on correlation between heterosis and the genetic distance based on simple sequence repeat markers indicated, the parental of 96 F1 hybrid at the genetic distance for 0.2547-0.5660, the correlation between heterosis of F1 seed setting rate,1000-grain weight and GD has negligible effect, the correlation between heterosis of effective panicles and GD has no significant correlation (r=011. r=0.14), However the correlation between heterosis of plant height and GD appeared to be significant at P<0.01 (r=0.44**、r=0.45**), the correlation between heterosis of panicle length and GD appeared to be significant at P<0.01 (r=0.39**、r=0.29**), the correlation between heterosis of total spikelets per panicle and GD appeared to be significant at P<0.01 (r=0.30**、r=0.32**), the correlation between mid-parent heterosis of spikelets per panicle and GD appeared to be significant at P<0.05(r=0.23*), and the heterobeltiosis appeared to be significant at P<0.01 (r=37**), the correlation between Yield per plant of spikelets per panicle and GD appeared to be significant at P<0.05 (r=0.23*), and the heterobeltiosis appeared to be significant at P<0.01 (r=34**). Therefore, at the parental genetic distance of 96 F1 hybrid for 0.2547-0.5660,the yield per plant can be predicted on simple sequence repeat markers, In ensuring the panicles per mu and setting rate to be stable。更多还原