【作者】 刘振宇；

【导师】 舒庆尧； 汪庆；

【作者基本信息】 浙江大学 ， 农艺与种业（专业学位）， 2021， 硕士

【摘要】 水稻是我国重要的粮食作物,巨大的人口基数对水稻需求提出了极高的要求。杂交水稻的应用显著提高了我国水稻产量,在保障粮食安全中发挥重要作用。不育系的异交特性对杂交水稻制种产量影响很大,特别是柱头的外露特性和活力,选育高柱头外露率（stigma exsertion rate,SER）和柱头活力（stigma vitality,SV）的不育系是提高制种产量和质量的重要途径。在本研究中,首先观察了多个遗传群体柱头外露率的遗传分离,其次分析了一个高柱头外露率连锁的数量性状位点（QTL,Quantitative trait locus）qSER-3.1在水稻亲本材料中的分布及在分离群体中与柱头外露率的相关性。再者,利用两个具有相同qSER-3.1等位基因但柱头外露率相差极大的材料开展了柱头外露率的QTL定位。最后,探索建立了一种基于过氧化氢酶活性的水稻柱头活力测定方法,分析了水稻基因型的差异。主要研究结果如下:1.不同组合水稻F₁和F₂/DH₂群体柱头外露率的表现。为探明不同水稻材料杂交后代的柱头外露率表现,对3个高柱头外露材料[TS848（81.1%）,TS849（75.7%）,ZS616（98.3%）]与6个低柱头外露材料[C703（0%）、SD2620（10.7%）、1350（0%）、B732（0.6%）、TS846（0%）、锡稻1号（0%）]的9个F₁、F₂/DH₂群体柱头外露率进行分析,发现F₁植株的柱头外露率比低柱头外露率亲本高,但总体偏向低柱头外露率亲本;在哈勃616S/锡稻一号的F₂植株和TS849/TS846的DH₂群体中,柱头外露率为正态分布;TS848与TS846、B732的3个F₂/DH₂群体中柱头外露植株较少,柱头外露率分布向低值亲本集中。上述结果说明水稻柱头外露率有两种遗传分离模式,遗传机理较为复杂。2.水稻柱头外露率QTL qSER-3.1在不同育种亲本及一个F₂群体中的分布。qSER-3.1是一个本实验室鉴定出的柱头外露率QTL,但在不同品种中分布及其在定位群体外与柱头外露率之间的关系尚未明确。因此,首先对100个哈勃616S/锡稻1号的F₂单株进行柱头外露率和qSER-3.1分析,发现携带qSER-3.1-ZS等位基因的材料柱头外露率为72.6%±6.9%,变幅12.7%～89.7%;携带qSER-3.1-DS等位基因的材料柱头外露率为19.5%±9.9%,变幅0%～28.2%。其次对180份亲本材料的柱头外露率和qSER-3.1的基因型进行了分析,发现20份携带qSER-3.1-ZS等位基因,158份携带qSER-3.1-DS等位基因,前者的柱头外露率平均为47.7%,显著高于后者的3.1%。上述结果说明,携带qSER-3.1-ZS等位基因的材料柱头外露率显著高于携带qSER-3.1-DS等位基因的材料是一个普遍现象。3.控制TS849高柱头外露率QTL的定位。TS849为一份高柱头外露材料,但与低柱头外露材料TS846一样携带qSER-3.1-ZS等位基因,表明其携带可提高柱头外露率的其它QTL。共获得TS846/TS849的93个花培DH₂系,分析了其柱头外露率。选取其中极低柱头外露（<12.6%）和极高柱头外露材料（>74.2%）各10个系,形成2个不同的柱头外露基因池。对两个池开展了二代测序,采用SNP-index,鉴定出了4个柱头外露率QTL:qSER-8.1（Chr8:20.48-22.46Mb）、qSER-10.1（Chr10:14.91-19.25 Mb）、qSER-11.1（Chr11:20.03-23.38 Mb）、qSER-12.1（Chr12:24.06-25.12Mb）。其中qSER-8.1、qSER-10.1、qSER-12.1与已报道的柱头外露率QTL在相近区间,qSER-11.1是新发现的QTL。4.水稻柱头活力测定方法的创建及品种间差异分析。以往柱头活力主要通过杂交,根据结实率进行间接测定,存在诸多弊端。本研究通过对TS948、TS992、TS9211、DH9070、TS256、TS248共6种水稻材料开花后连续6天过氧化氢酶活性测定和开花后连续6天人工授粉的结实率分析,发现两种方法测得的柱头活力存在极显著相关,从而建立起了一种基于过氧化氢酶活性测定的柱头活力检测方法。以此方法进行品种间柱头活力差异分析,发现开花后柱头活力都逐渐下降,但紫色柱头材料的柱头活力下降速度慢于白色柱头材料,而且开花当日下午5:00喷施30mg/L赤霉素溶液可以延缓柱头活力的下降。本论文通过对水稻柱头外露率遗传与柱头活力基因型差异的研究,揭示了柱头外露率在不同群体中的遗传特点,验证了一个QTL qSER-3.1鉴定高柱头外露率水稻的有效性,定位了高柱头外露率材料TS849的柱头外露率QTL,创建了一种新的水稻柱头活力测定方法,对水稻不育系异交特性改良、提高杂交制种产量有着积极意义。更多还原

【Abstract】 Rice is an important food crop in China,our huge population calls for high demands on rice.The application of hybrid rice technology has significantly increased rice yield and has played an important role in ensuring food security.In hybrid seed production,the outcrossing characteristics of male sterile lines,especially stigma exsertion rate（SER）and stigma vitality,has a great impact on seed yield and quality.Male sterile lines with a high stigma exsertion rate and stigma vitality is a vital to improve yield and quality in hybrid seed production.In this study,firstly,we observed the genetic segregation of SER in several genetic populations.Secondly,we analyzed the distribution of the SER QTL--qSER-3.1 in rice breeding parent lines and a segregating population and its correlation with SER.Then,two rice lines with the same qSER-3.1 allele but having different SERs were used as parents to create a doubled haploid（DH）population and used for QTL mapping of SER.Finally,we explored and established a method for measuring rice stigma vitality based on catalase activity,after which we analyzed the variation of it in different rice genotypes.The main findings are as follows:1.The SER performance in F₁ and F₂/DH₂ populations of different rice lines.To clarify the rice SER performance of filial generation from diverse materials,we analyzed the SER of F₁ and F₂/DH₂ populations derived from crosses of 3 high SER lines[TS848（81.1%）,TS849（75.7%）,Hupper 616S（98.3%）]and 6 low SER lines[C703（0%）,SD2620（10.7%）,1350（0%）,B732（0.6%）,TS846（0%）and Xidao No.1（0%）].It was found that the SER of F₁ plants was higher than that of the parents with the low SER,but was more inclined to the parents with low SER.The SER of F₂ plants of Hupper 616S/Xidao No.1 and the F₂/DH₂ plants/lines of TS849 crossed to TS846and B732 showed normal distribution.However,there were only a few F₂ plants/DH₂lines derived from TS848 having a high SER,majority of its F₂ plants/DH₂ lines had very low SERs.The above results indicate that there are two different inherited separation pattern,the genetic mechanism of rice SER is complicated.2.The distribution of SER QTL qSER-3.1 in diverse parents and in a F₂ population.qSER-3.1 is a SER QTL identified by our team,but the distribution in diverse varieties and the relation with SER in other genetic populations remained unclear.Consequently,we analyzed the SER and qSER-3.1 genotype of 100 F₂ plants developed from cross of Hupper 616S/Xidao No.1 initially,it was found that the SER of lines carrying qSER-3.1-ZS allele was 72.6±6.9%（with the range 12.7～89.7%）,and 19.5±9.9%（with a range 0～28.2%）carrying the qSER-3.1-DS allele.Subsequently,the SER and genotype of qSER-3.1 of 180 parental lines were analyzed,it was found that 20 carried the qSER-3.1-ZS allele,158 carried the qSER-3.1-DS one.The former lines showed higher SERs（47.7%±18.7%）as compared to the latter ones（3.1%±10.3%）.The above results indicate it is universal that the SER of qSER-3.1-ZS lines is significantly higher than qSER-3.1-DS ones.3.Mapping of high SER QTLs in TS849.TS849 is a high SER material,but it carries the qSER-3.1-ZS allele the same as TS846,a line with low SER,which indicates that they may carry new QTLs other than qSER-3.1.A total 93 DH₂ lines were developed from the of TS846/TS849 F₁ plants and analyzed for SER.Out of them,10 lines with extremely low SER（<12.6%）and 10 with extremely high SER materials（>74.2%）were selected for the development of 2 sequencing pools,of which the genomes were sequenced using next generation sequencing.Four QTLs related to SER were identified through SNP-index:qSER-8.1（20.48-22.46 Mb of Chr 8）,qSER-10.1（14.91-19.25 Mb of Chr 10）,qSER-11.1（20.03-23.38 Mb of Chr 11）,qSER-12.1（24.06-25.12Mb of Chr12）.Among them,qSER-8.1,qSER-10.1,qSER-12.1 are overlapped with previously reported SER QTLs,while qSER-11.1 is a new one.4.Establishment of a method for measuring rice stigma vitality and its use for analysis of different rice varieties.The determination of rice stigma vitality by crossing and examination of seed set rate was a commonly used method,but it has several drawbacks.In this study,we analyzed the catalase activity and seed set rate after manual pollination of TS948,TS992,TS9211,DH9070,TS256 and TS248 for 6consecutive days after flowering,it was found that the correlation between the two methods is extremely significant,hence a method for measuring stigma vitality based on the determination of catalase activity was established.Using this method to analyze the difference in stigma vitality between varieties,it was found that the stigma vitality decreased gradually after flowering,but the stigma vitality of the purple stigma material decreased slower than that of the white stigma material.Spraying 30mg/L gibberellin at 5:00 pm on the flowering day can delay the decline of stigma vitality.In this thesis,through the study on the inheritance of stigma exsertion rate and genotypical variation of stigma vitality in rice,we revealed the genetic characteristics of SER in different populations,verified the validity of qSER-3.1 to breed rice with a high SER,identified new SERQTLs in TS849,and established a new method for measuring stigma vitality of rice,which together will have a positive impact on improving outcrossing characteristics of male sterile rice for improving yield in hybrid seed production.更多还原