【作者】 蒋开锋；

【导师】 吴先军； 汪旭东； 郑家奎；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2007， 博士

【摘要】 培育高产稳产、对环境钝感的优质杂交稻新组合已成为当前水稻育种的最重要的目标;近年高温造成水稻结实率显著下降而导致产量的严重损失,水稻耐热性的改良也日益迫切。本文用我省育成的5个代表性优质不育系组配的24个不完全双列杂交组合,通过四川有生态代表性的四个试点试验,在消除以往同类研究存在的环境效应和基因与环境互作效应影响的基础上,系统地研究了杂交稻产量性状、品质性状及其稳定性的遗传与相关性,其中:品质性状的稳定性与其他性状的相关性研究结果为首次报道,并探讨了我省培育高产稳产、对环境钝感的优质杂交稻组合的可能技术途径。用中优早8号/丰锦杂交后代的168个籼粳交重组自交系群体和157个SSR分子标记构建的遗传连锁图谱,以自然常温和高温结实率的差值作为耐热指数,采用复合区间作图法,对抽穗扬花期的耐热性进行了QTL分析,在第2、3、5连锁群上检测到3个新的耐热QTLs。根据Wx~a和Wx~b的序列差异,建立了两个新的STS标记,开展了不育系直链淀粉含量分子标记辅助育种研究,育成的一个优质不育系通过省级鉴定,并组配出3个组合参加各级区试。旨在为我省高产稳产、对环境钝感的优质杂交稻新组合选育、耐热性遗传改良提供理论参考和奠定技术基础。主要研究结果如下:1.杂交稻产量和品质性状的遗传和相关研究1.1供试组合比汕优63增产的组合数(30.43%)较少、增幅不大(0.66～4.05%),主要原因在于不育系的配合力较低、杂交稻组合的结实率低;垩白粒率高、垩白度大和整精米率较低是杂交稻品质存在的主要问题。1.2产量和粒长、粒宽、长宽比、垩白粒率、垩白度、糙米率、精米率、整精米率、直链淀粉含量、胶稠度和碱消值的基因型效应、试点效应均达到1%显著水平,除碱消值外的其余性状,基因型与试点的互作效应也达到1%显著水平。表明产量和品质性状的遗传改良和稳定性评价都很重要。1.3双亲配合力改良和组合的选配,对杂交稻的产量提高和除碱消值外的品质改善都有显著效果。产量以恢复系改良的作用最大(相对重要性62%,下同),依次是不育系配合力改良(24%)和组合的评价筛选(14%);品质以不育系改良的作用最大,但不同指标各部分的相对重要性不同,改良的策略也应不同。1.4品质性状中垩白粒率、垩白度的稳定性最差,整精米率、胶稠度和直链淀粉含量的稳定性较差,长宽比和糙米率等稳定性高;宜宾点对垩白粒率和垩白度、南充点对直链淀粉含量、作物所点对整精米率和胶稠度的鉴别力最强。1.5品质性状间的相关分析表明,所有品质指标完美结合有一定难度。外观、加工和食味品质内的品质指标间,都存在有利于彼此促进、共同协调改良的显著或极显著相关性;增大粒长和长宽比有利于外观和食味品质改善,但不利于整精米率提高;直链淀粉含量提高有利于提高整精米率。1.6产量性状与品质性状的相关分析表明,优质与高产结合有一定难度,主要表现在高产需增加单穗重,单穗重提高不利于外观品质改良、而有利于整精米率提高;穗数型的产量性状构成对整精米率提高不利,而有利于其它品质性状的改良。1.7品质性状与其稳定性相关分析表明,单一品质性状的稳定性参数与其表型值之间的相关均未达显著水平,培育对环境钝感的优质稻是可能的;各品质指标间,垩白度大的糙米率和精米率的稳定性差,增加垩白粒率和垩白度的稳定性有利于提高整精米率,增强低垩白粒率和小垩白度稳定性的间接选择,对改善外观品质和加工品质都有重要作用。1.8丰产性与稳产性之间的相关,丰产性和稳产性分别与各品质性状稳定性之间的相关,各品质性状稳定性之间的相关,均不显著,表明丰产性、稳产性和综合稻米品质的稳定性可能较好的结合。2.水稻抽穗期耐热性的QTL分析2.1检测到qhts-2、qhts-3、qhts-5 3个加性效应显著的耐热性QTLs,分别位于第2、3、5连锁群上。单变异的贡献率为6.59%～10.72%,联合贡献率为28.01%;位于第3染色体的qhts-3的效应最大,贡献率达10.72%,基因作用方式为加性;位于第5染色体的qhts-5的效应次之,贡献率为10.70%,基因作用方式主要为超显性;位于第2染色体的qhts-2的效应最小,贡献率为6.59%,基因作用方式主要为超显性。其中,qhts-2和qhts-5是首次在第2和第5连锁群上检测到的两个耐热QTLs;qhts-3与已报道的第3连锁群位于RZ892和RG100区间的唯一1个耐热QTL,位置不同,是一个新的耐热QTL。1.2程式指数与常温结实率、高温结实率及耐热指数的相关均不显著,表明该RIL群体的偏粳分离对耐热性指数不存在影响;常温结实率与高温结实率和耐热指数呈极显著正相关,高温结实率与耐热指数呈极显著负相关,表明常温条件高结实率的材料,在高温条件下通常结实率也较高,耐热性选择应在常温和高温条件下对高结实率性状同时进行。3.直链淀粉含量的分子标记辅助选择3.1建立了两个STS显性标记Wi10-1和Wi10-2,分别特异性识别非糯稻Wx等位基因Wx~b和Wx~a。3.2两个标记与直链淀粉含量的相关系数高达0.905,能准确识别Wx~bWx~b和Wx~aWx~a。3.3应用建立的新标记,对不育系选育过程中的低世代不育株和保持系单株进行辅助选择,育成的优质不育系泸香618A通过了四川省技术鉴定,并组配出3个优质杂交稻组合参加各级区试。更多还原

【Abstract】 Now,cultivation of the good quality and new rice(Oryza sativa L.) hybrid combinations,which are insensitive to environment with high and steady yield,has been the most important goal for rice breeding.Improvement of heat tolerance of rice is getting more and more stringent,as seed setting rate decreasing remarkably caused by high temperature resulted in serious lost of rice yield in recent years.In this paper,in order to avoid influences from environment and interactive effect of environment and genotype,the inheritance of grain yield and quality traits,the correlation and the stability among these traits were studied systematically by utilization of the data come from the experiment in 4 ecological trial places representing different environment in Sichuan Province,and 24 diallel crossing combinations derived from 5 cytoplasm male sterile lines and 3 restorer lines of good rice quality besides zhenshan97A and Minghui63.Among the total,the research results of stability of the quality characters,correlation of the quality characters and other characters were reported for the first time,and the possible technical routes for breeding good quality hybrid rice combinations that are insensitive to environment with high and steady yields in our province were discussed.The genetic linkage map including 157 SSR markers was constructed with a recombinant inbred line(RIL) population consists of 168 lines from a cross of Oryza sativa indica Zhongyouzao No.8 and Oryza sativa japonica Fengjin,and the quantitative traits loci(QTL) analysis on heat tolerance in earing period was done by using composite interval graphic method and the difference of seed setting rate between normal and high temperature as heat resistance index.Three new heat tolerance QTLs were detected in the second,third,fifth linkage groups,respectively. According to the reported sequence difference between waxy gene Wx~a and Wx~b of non-glutinous rice,two pairs of dominant sequence tag site(STS) molecular markers were designed to distinguish Wx~a from Wx~b based on the special site between the two genotypes, moreover,the two markers were used for study on improving quality of cytoplasm male sterile line by marker-assisted selection method,and a high-quality sterile line passed the Province-level assessment,and 3 combinations participated in region test trials.The purpose for this study is to provide theoretical references and technical foundations for the breeding of the good quality and new hybrid combinations,which are insensitive to environment with the high and steady yield and the rice genetic improvement of heat resistance.The main findings are as follow:1.Genetic and correlation researches of yield and quality traits of hybrid rice1.1 The main reasons for less combination numbers(30.43%) and lower increasing range (0.66～4.05%) in grain yield than Shanyou63 were lower seed-setting rate of experimental combinations and lower general combining ability of cytoplasm male sterile lines. Comparing the national standard for good quality rice with the index of experimental combinations,the key problems were higher chalky grain rate bigger chalky degree and lower head rice rate.1.2 Genotype effect and trial effect of rice yield,grain length,grain width,ratio of grain length and width,chalky grain rate,chalky degree,brown rice rate,milling rice rate,head rice rate,amylose content,gel consistency and gelatinization temperature were significant at 1%level,the interactive effects between genotype and site for all traits except GT were significant at 1%level too,which implied that the genetic improvement and stability evaluation of rice yield and quality characters are both important.1.3 Both improvement of combination ability of parents and aplegamy of combinations have significant effects on higher yield and quality characters except gelatinization temperature.Improvement of restorer lines play the most important role in yield(62% relative importance),the next is combination of sterile lines(24%),evaluation and screening of combinations(14%).The sterile lines play the most important role in quality improvement,but relative importance is different for different rice breeding targets,and the strategies of rice improvements should be different too.1.4 Of all the quality characters,chalky grain rate and chalky degree were of lowest stability,head rice rate,gel consistency and amylose content were of lower stability,but grain length and width ratio,brown rice rate and other traits were of higher stability. Among 4 trial sites,there was the best discriminating ability for chalky grain rate and chalky degree in Yibin,amylose content in Nanchong,head rice rate and gelatinization temperature in Chengdu of Sichuan Province,respectively.1.5 The correlation analysis among rice quality characters indicates that it is hard to combine all the quality characters perfectly.There are facilitative significant or extremely significant correlations among appearance characters,processing and flavor characters;and to increase grain length or grain length and width ratio are good for the improvement of the appearance and flavor characters,but not good for promoting the head rice rate and milling rice rate.The increasing of amylose content is facilitative to the addition of the head rice rate.1.6 The correlation analysis between the rice yield character and quality character indicates that it is not easy to combine high quality and high yield.The main reason is that high yield needs more single-ear weight which is harm to the appearance quality but good to the head rice rate.The yield character constitution of ear number type is harm to the head rice rate but good to other quality character improvements.1.7 The correlation analysis between rice quality and its stability indicates that there is no significant correlation between stable index of single quality character and its phenotypic value,so it is possible to breed varieties of high-quality rice insensitive to environment. High chalky degree is harm to stability of the brown rice rate and milling rice rate,and promoting the stability of the chalky grain rate and chalky degree are positive to the head rice rate.The indirect selection of stability of low chalky grain rate and low chalky degree are important for the improvement of the appearance and processing characters.1.8 All of the correlation coefficient among rice yield,its stability and stability of every quality trait were not significant;which implied it was possible to combine high yield with stability of yield and the quality traits.2.QTL analysis of rice heat tolerance in heading period2.1 By composite interval mapping method of software windows QTL Cartographer 2.0,it was determined that three heat tolerance QTLs qhts-2,qhts-3 and qhts-5 with significant additive effects located in the second,third,fifth linkage groups respectively,the rang of contribution rate was from 6.59%to 10.72%,the co-contribution rate was 28.01%.The action manner for qhts-3 was mainly additive effect;qhts-2 and qhts-5 were mainly over-dominant effects.The heat tolerance QTL qhts-2 and qhts-5 detected in the second and fifth linkage groups were reported for the first time.The qhts-3 is a new QTL,which location is different from the only heat tolerance QTL previously reported between markers RZ892 and RG100 in the third linkage groups.2.2 The correlation between the Cheng’s index and heat tolerance index,spikelet fertility of the RIL population under natural field and high temperature environment was not significant,repetitively,which implied that the RIL population of japonicalinous distribution didn’t impact on QTL mapping.The extremely significant positive correlation between spikelet fertility under natural field and high temperature environment,and between heat tolerance index and spikelet fertility under natural field and high temperature environment respectively,but extremely significant negative correlation between rate of high temperature seed setting and the heat tolerance index,implied that it was very necessary for selection of heat tolerance material to be conducted under normal and high temperature environment.3.Molecular marker assisted selection of amylose content in rice3.1 Two sequence tag site(STS) dominant markers Wi10-1 and Wi10-2 specially identifying non- glutinous rice Wx allele genes Wx~b and Wx~a were constructed.3.2 The two molecular markers,the correlation coefficient between which and amylase content is up to 0.905,can accurately identify Wx~bWx~b and Wx~aWx~a.3.3 The designed two markers were used to breed cytoplasm male sterile line of hybrid rice by marker-assisted selection for Wx allele genes Wx~b during lower generation’s period of maintainer and cytoplasm male sterile line.A new cytoplasm male sterile line Luxiang 618A with good quality was bred and has passed technical identification in Sichuan Province in 2006;moreover,three good quality combinations derived from Luxiang 618A have taken part in national or provincial rice region experiment.更多还原