东乡野生稻回交重组系的抗旱性评价体系

选用协青早B//东乡野生稻/协青早B回交重组系及其亲本共79份水稻材料,研究了水稻发芽期、苗期、孕穗期、成熟期的种子萌发抗旱指数等31个指标与东乡野生稻回交重组系抗旱性的关系.结果表明:15％ PEG-6000溶液处理的相对发芽势、20％ PEG-6000溶液处理的种子萌发抗旱指数和相对发芽势及水分胁迫后最长根长、苗高、根鲜质量、根干质量、根系相对含水量、萎蔫率、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、叶片相对含水量、卷叶级别、株高、单株分蘖数、单株有效穗数、穗实粒数、着粒密度、结实率、千粒重等21个指标的相对值与抗旱系数或抗旱指数的相关性显著.通过逐步回归分析筛选出9个抗旱性鉴定指标:20％ PEG-6000溶液处理的相对发芽势及水分胁迫后根干质量、根系相对含水量、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、单株有效穗、结实率和千粒重的相对值.根据这些指标和偏相关系数,建立了不同时期的抗旱性评价(D值)方程和评价体系,可对东乡野生稻回交重组系抗旱性进行较好的评价.     

浓硫酸处理对海滨木槿10个家系种子萌发的影响

以海滨木槿10个家系种子为材料,采用浓硫酸不同时间(0、10、15和20 min)处理,测定种子发芽率、发芽势、发芽指数及萌发过程中相对吸水率、可溶性糖、淀粉和α-淀粉酶含量,研究浓硫酸处理对海滨木槿种子萌发的影响以及不同家系间种子萌发差异.结果表明:浓硫酸处理显著提高了海滨木槿种子的发芽率、发芽指数和发芽势,缩短了发芽时间.浓硫酸处理15 min后,种子发芽率、发芽势和发芽指数分别为95.7％、91.3％和13.28,萌发时间最短,效果最佳.海滨木槿不同家系间种子发芽率、发芽势和发芽指数差异显著,最高发芽指数(15.13)是最低发芽指数(7.15)的2.12倍,最高发芽势(98.0％)是最低发芽势(55.5％)的1.77倍.浓硫酸处理可加快海滨木槿种子萌发代谢生理生化进程.相对吸水率、可溶性糖和α-淀粉酶均呈单峰曲线变化(先升后降),在萌发初期达到最大值;淀粉含量与种子发芽指数呈显著负相关.     

意大利苍耳二形性种子萌发、植株生长差异及生态适应性

意大利苍耳(Xanthium italicum)是一种具有二形性种子的一年生菊科植物,每个头状花序仅产生1粒上位种子和1粒下位种子.意大利苍耳种子产量高,对环境的适应能力强,能给农作物和生态环境造成严重危害.对意大利苍耳的种子萌发和植株生长特性进行了观测研究,探讨了其生态适应性.结果表明:(1)下位种子从播种到50%萌发需要13～15d,比上位种子早5～7d;(2)下位植株主茎第1～7片叶的发育中期单位时间内的叶面积增量、同期株高显著大于上位植株;然而上位植株主茎第9～13片叶的发育早、中期单位时间内的叶面积增量反而大于下位植株;上、下位植株主茎上第8、14片叶和第15片叶的各阶段单位时间内的叶面积增量没有差异;(3)下位植株的一级分枝数和二级分枝数显著多于上位植株.推断下位种子较上位种子具有更强的生存竞争能力,下位种子对意大利苍耳种群的延续、增长和扩散贡献更大;同时上位种子为种群的稳定延续提供了保障,这种二形性种子的形成是意大利苍耳的一种有效的生态对策.     

水稻耐盐相关动态QTL的加性和上位性与环境互作分析

钠离子(Na⁺)、钾离子(K⁺)含量和Na⁺/K⁺值是影响水稻耐盐性的关键指标。水稻的耐盐性由数量性状位点(QTL)控制,目前在水稻苗期已经鉴定了大量Na⁺、K⁺含量和Na⁺/K⁺的QTL,但在田间生长期鉴定的QTL数量较少。该研究以粳稻‘东农425’和‘长白10’杂交衍生的重组自交系(RIL)群体为材料,对田间试验条件下的盐胁迫和对照进行联合分析,在水稻不同发育时期鉴定Na⁺、K⁺含量和Na⁺/K⁺的发育动态QTL,并采用混合线性模型(MCIM)分析各QTL的加性(A)和上位性(AA)及其与环境的互作效应(QE)。结果表明：(1)盐胁迫条件下,亲本和RIL群体的茎Na⁺含量(SNC)、茎Na⁺/K⁺(SN/K)、叶Na⁺含量(LNC)和叶Na⁺/K⁺(LN/K)在各时期均高于对照,茎K⁺含量(SKC)和叶K⁺含量(LKC)均低于对照,对照条件下双亲性状在大多数时期均无显著差异;盐胁迫下两个亲本的多个性状在不同发育时期存在显著差异,其中,SNC和LKC在4个时期差异显著,SN/K和LN/K在3个时期差异显著,SKC和LNC在2个时期差异显著。(2)采用非条件和条件QTL作图方法,共检测到13个加性QTL和11对上位性QTL,其中包括14个非条件QTL和10个条件QTL;而13个加性QTL中有8个,11对上位性QTL中有7个具有环境互作效应。(3)qSKC5 1在水稻4个发育阶段均被检测到,其在调控水稻耐盐性中发挥着重要作用。SNC、SN/K和LN/K的所有QTL均检测到加性×环境互作效应,2对控制SNC的上位性QTL均检测到上位性×环境互作效应,说明这些性状的QTL对盐环境较为敏感。研究发现,田间生长条件下水稻Na⁺、K⁺含量和Na⁺/K⁺的QTL表达与发育时期密切相关;水稻田间生长条件下耐盐性的遗传非常复杂,在利用分子标记辅助选择(MAS)培育耐盐水稻新材料应该考虑上位性和环境互作效应。     

水稻生物学产量及其构成性状的QTL定位

QTL的加性效应、加性×加性上位性效应及它们与环境的互作效应是数量性状的重要遗传分量.利用IR64/Azucena的125个DH品系为群体,分析了水稻生物学产量及其两个构成性状干草产量和谷粒产量的遗传组成.用基于混合模型的复合区间作图(MCIM)方法进行QTL定位.检测到12个位点有加性主效应,27个位点涉及双位点互作,18个位点存在环境互作.结果表明水稻生物学产量和它的两个构成性状普遍存在上位性效应和QE互作效应.此外,还探讨了性状间相关的遗传基础.发现4个QTLs和一对上位性QTLs可能与生物学产量与干草产量之间的正相关有关.3个QTL可能与干草产量与谷粒产量之间的负相关有关.这些结果可能部分地解释了这3个性状相关的遗传原因.通过对水稻生物学产量及其两个构成性状所定位QTL的分析,加深了对数量性状QTL的认识.首先,QTL的上位性效应和QE互作效应是普遍存在的;其次,QTL的多效性或紧密连锁可能是遗传相关的原因,当QTL对两个性状作用的方向相同时可导致正向遗传相关,反之则为负向遗传相关,当有些QTL表现为同向作用而另一些QTL表现为反向作用时,则可削弱性状间的遗传相关性;第三,复合性状的QTL效应可分解为其组成性状的QTL效应,如果QTL对各组成性状的效应方向相反而相互抵消,可使复合性状的QTL效应不易被检测;第四,加性效应的QTL常参预构成上位性效应,而具有上位性效应的QTL并非都有加性主效应,表明忽略上位性的QTL定位方法会降低检测QTL的功效;最后,鉴别不同类型的QTL效应有利于指导育种实践,选择主效QTL适用于多环境,QE互作QTL适用于特定环境,对上位性QTL应强调选择基因组合而并非单个基因.     

水稻籼粳交DH群体苗期耐冷性基因的分子标记定位

水稻苗期低温冷害导致的烂秧现象是水稻生产中重要的限制因素之一。以一个水稻籼粳交(圭630／02428)DH群体为材料,在幼苗3叶1心时用10℃低温处理3d,随后恢复培养,以恢复培养5d后的秧苗成活率(％)为指标,鉴定该DH群体的苗期耐冷性。利用已构建的RFLP连锁图谱和基于混合线性模型的定位软件QTLMapper1.0对水稻苗期耐冷性进行QTL分析,检测到控制水稻苗期耐冷性的3个QTLs,分别位于第3、11、12染色体上,贡献率分别为7．9％、18．3％和24.4％,其增效等位基因均来自于亲本“02428”。同时检测到控制水稻苗期耐冷性的上位性互作位点8个,分散分布于第2、7、8、9、11染色体上,其中有2对互作的贡献率在15％左右,这2对互作的增效基因型均为来自2个亲本的重组基因型。苗期耐冷性在2个亲本间差异很大,在DH群体中呈现出连续变异,有明显的超亲分离。这些结果表明,水稻苗期耐冷性是受多基因控制的数量性状,基因的上位性互作是其重要的遗传基础之一。     

水稻苗期生长对缺磷响应的QTL定位(英文)

缺磷是抑制全球水稻产量主要因素之一。本研究利用Asomonori(粳型)/IR24(籼型)杂交重组自交株系,对5个水稻苗期性状(相对苗高、相对根长、相对根重、相对苗重以及相对总重)在缺磷条件下的响应QTL进行定位。共检测到20个水稻苗期生长对缺磷响应的QTL位点,分别位于第1(4QTLs)、第4(4QTLs)、第5(2QTLs)、第7、第8(4QTLs)、第9(2QTLs)、第11(2QTLs)和第12号染色体上,其中13个QTLs位于与C3029C、XNpb302、C621B、C621C、R2976和C1263分子标记紧密连锁的6个基因组区域上。另外,每个性状均能从双亲中检测到正负效应QTL位点,这些能解释重组自交系群体中出现超亲和连续分布的现象。本文主要报道了水稻第5、第7和第11染色体上存在水稻苗期生长对缺磷响应的QTL位点。研究表明,该结果及其中检测到的QTLs两侧的连锁分子标记可用于水稻苗期耐低磷性分子育种。     

水稻种子抗老化遗传分析

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板蓝根种子的吸水特性及发芽条件研究

采用室内测定方法,对板蓝根种子的吸水特性及不同处理下种子的发芽率、发芽势和相对活力指数等进行比较研究。结果表明,板蓝根种子具有快速吸水的生物学特性,分为快速吸水期、缓慢吸水期和缓慢吐水期三个阶段,入水后2 h的吸水量达最大吸水量的73.29%,为快速吸水阶段;温度对板蓝根种子的萌发影响较大,最适发芽温度为30℃。光照、发芽床和种子预处理对板蓝根种子的萌发无明显影响。这说明板蓝根种子的萌发主要取决于水分和温度。     

水稻发芽期和幼苗前期耐碱性的鉴定方法研究

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Identification of Quantitative Trait Loci for ABA Sensitivity at Seed Germination and Seedling Stages in Rice

Abscisic acid (ABA) is one of the important plant hormones, which plays a critical role in seed development and adaptation to abiotic stresses. The sensitivity of rice (Oryza sativa L.) to exogenous ABA at seed germination and seedling stages was investigated in the recombinant inbred line (RIL) population derived from a cross between irrigated rice Zhenshan 97 and upland rice IRAT109, using relative germination vigor (RGV), relative germination rate (RGR) and leaf rolling scores of spraying (LRS) or culturing (LRC) with ABA as sensitivity indexes. The phenotypic correlation analysis revealed that only RGV at germination stage was positively correlated to ABA sensitivity at seedling stage. QTL detection using composite interval mapping (CIM) and mixed linear model was conducted to dissect the genetic basis of ABA sensitivity, and the single-locus QTLS detected by both methods are in good agreement with each other. Five single QTLs and six pairs of epistatic QTLs were detected for ABA sensitivity at germination stage. Eight single QTLs and five pairs of epistatic QTLs were detected for ABA sensitivity at seedling stage. Two QTLs were common between LRS and LRC; and one common QTL was detected for RGV, LRS and LRC simultaneously. These results indicated that both single and epistatic loci were involved in the ABA sensitivity in rice, and the genetic basis of ABA sensitivity at seed germination and seedling stage was largely different.     

水稻耐储藏特性三年动态鉴定与QTL分析

种子耐储藏特性是粮食作物的特殊农艺性状之一, 耐储藏性能对种子生产和种质资源保存有重要意义。以粳型超级稻龙稻5 (LD5)和高产籼稻中优早8 (ZYZ8)杂交衍生的重组自交系(RILs)群体(共180个株系)为实验材料, 自然高温高湿条件下放置1年、2年和3年后, 对不同储藏时段种子发芽率进行比较, 并利用223个分子标记的遗传图谱进行动态QTL鉴定。结果表明, 不同储藏时段龙稻5的发芽率均显著低于中优早8, 株系间耐储性存在较大差异; 不同储藏时段发芽率显著相关, 相邻存储时段发芽率关系紧密。共检测到17个耐储性相关的QTLs, 3个老化时段分别检测到5、4和3个, 检测到5个动态条件QTLs, 单一QTL解释5.60%-32.76%的表型变异, 加性效应在-16.78%-16.95%范围内。主效QTL簇qSSC2、qSSC6、qSSC7和qSSC8能调控不同储藏时段的发芽率, qSSC6具有明显降低发芽率的效应。共检测到26对上位性互作位点, 主效QTL qSS1和qSS4参与上位性互作, 这表明上位性互作是调控耐储藏性状的重要遗传组成。研究结果为水稻(Oryza sativa)耐储性相关QTL的精细定位奠定基础, 同时丰富了耐储性分子标记辅助选择育种的基因资源。     

水稻耐储藏特性三年动态鉴定与QTL分析

种子耐储藏特性是粮食作物的特殊农艺性状之一, 耐储藏性能对种子生产和种质资源保存有重要意义。以粳型超级稻龙稻5 (LD5)和高产籼稻中优早8 (ZYZ8)杂交衍生的重组自交系(RILs)群体(共180个株系)为实验材料, 自然高温高湿条件下放置1年、2年和3年后, 对不同储藏时段种子发芽率进行比较, 并利用223个分子标记的遗传图谱进行动态QTL鉴定。结果表明, 不同储藏时段龙稻5的发芽率均显著低于中优早8, 株系间耐储性存在较大差异; 不同储藏时段发芽率显著相关, 相邻存储时段发芽率关系紧密。共检测到17个耐储性相关的QTLs, 3个老化时段分别检测到5、4和3个, 检测到5个动态条件QTLs, 单一QTL解释5.60%-32.76%的表型变异, 加性效应在-16.78%-16.95%范围内。主效QTL簇qSSC2、qSSC6、qSSC7和qSSC8能调控不同储藏时段的发芽率, qSSC6具有明显降低发芽率的效应。共检测到26对上位性互作位点, 主效QTL qSS1和qSS4参与上位性互作, 这表明上位性互作是调控耐储藏性状的重要遗传组成。研究结果为水稻(Oryza sativa)耐储性相关QTL的精细定位奠定基础, 同时丰富了耐储性分子标记辅助选择育种的基因资源。     

Dynamic Quantitative Trait Loci Analysis of Seed Reserve Utilization during Three Germination Stages in Rice

In this study, one rice population of recombinant inbred lines (RILs) was used to determine the genetic characteristics of seed reserve utilization during the early (day 6), middle (day 10) and late (day 14) germination stages. The seedling dry weight (SDW) and weight of the mobilized seed reserve (WMSR) were increased, while the seed reserve utilization efficiency (SRUE) decreased, during the process of seed germination. The SDW and WMSR were affected by the seed weight, while the SRUE was not affected by the seed weight. A total of twenty unconditional and twenty-one conditional additive QTLs and eight epistatic QTLs were identified at three germination stages, and the more QTLs were expressed at the late germination stage. Among them, twelve additive and three epistatic QTLs for SDW, eight additive and three epistatic QTLs for WMSR and thirteen additive and two epistatic QTLs for SRUE were identified, respectively. The phenotypic variation explained by each additive QTL, epistatic QTL and QTL × development interaction ranged from 6.10 to 23.91%, 1.79 to 6.88% and 0.22 to 2.86%, respectively. Two major additive QTLs qWMSR7.1 and qSRUE4.3 were identified, and each QTL could explain more than 20% of the total phenotypic variance. By comparing the chromosomal positions of these additive QTLs with those previously identified, eleven QTLs might represent novel genes. The best four cross combinations of each trait for the development of RIL populations were selected. The selected RILs and the identified QTLs might be applicable to improve rice seed reserve utilization by the marker-assisted selection approach.     

小麦幼苗耐热性的QTL定位分析

以小麦DH群体(‘旱选10号’ב鲁麦14’)为材料,在高温(热胁迫)及常温(对照)两种条件下考察小麦幼苗的根干重、苗干重、幼苗生物量、叶片叶绿素含量、叶绿素荧光参数及其耐热指数,并应用基于混合线性模型的复合区间作图法分析幼苗性状及其耐热指数QTL的数量、染色体分布及表达情况,以及QTL与环境的互作效应。结果显示:(1)亲本‘旱选10号’的耐热性明显优于‘鲁麦14’,且杂交后代的耐热性出现超亲分离。(2)控制幼苗耐热相关性状的QTL位点在染色体2D、6B、3A、4A、5A和7A上分布较多,而控制幼苗性状耐热指数的QTL在染色体6A、6B、3A、2D、5A和7A上分布较多,QTL位点在染色体上的分布有区域化的趋势。(3)控制幼苗性状的单个加性QTL和上位性QTL解释的表型变异分别平均为2.48%和2.65%;而控制耐热指数的单个加性QTL和上位性QTL解释的表型变异分别平均为8.84%和1.98%。(4)在热胁迫和对照条件下共检测到与幼苗性状及其耐热指数有关的加性效应QTL 13个和上位性效应QTL 28对,分布在除4D和6D以外的19条染色体上。研究表明,控制幼苗性状的QTL以上位性效应为主,而其耐热指数的QTL以加性效应为主。     

Dynamic Quantitative Trait Locus Analysis of Seed Vigor at Three Maturity Stages in Rice

Seed vigor is an important characteristic of seed quality. In this study, one rice population of recombinant inbred lines (RILs) was used to determine the genetic characteristics of seed vigor, including the germination potential, germination rate, germination index and time for 50% of germination, at 4 (early), 5 (middle) and 6 weeks (late) after heading in two years. A total of 24 additive and 9 epistatic quantitative trait loci (QTL) for seed vigor were identified using QTL Cartographer and QTLNetwork program respectively in 2012; while 32 simple sequence repeat (SSR) markers associated with seed vigor were detected using bulked segregant analysis (BSA) in 2013. The additive, epistatic and QTL × development interaction effects regulated the dry maturity developmental process to improve seed vigor in rice. The phenotypic variation explained by each additive, epistatic QTL and QTL × development interaction ranged from 5.86 to 40.67%, 4.64 to 11.28% and 0.01 to 1.17%, respectively. The QTLs were rarely co-localized among the different maturity stages; more QTLs were expressed at the early maturity stage followed by the late and middle stages. Twenty additive QTLs were stably expressed in two years which might play important roles in establishment of seed vigor in different environments. By comparing chromosomal positions of these stably expressed additive QTLs with those previously identified, the regions of QTL for seed vigor are likely to coincide with QTL for grain size, low temperature germinability and seed dormancy; while 5 additive QTL might represent novel genes. Using four selected RILs, three cross combinations of seed vigor for the development of RIL populations were predicted; 19 elite alleles could be pyramided by each combination.     

水稻种子活力QTL定位及上位性分析

利用1个粳／籼交来源(Lemont／Teqing)、包含264个重组自交系的作图群体,采用纸卷法在18℃培养箱中进行2次重复的发芽实验,考察了种子发芽7d、9d和1ld的发芽率,种子发芽15d后的芽长及干重等种子活力的相关性状。结合一张含有198个DNA标记的连锁图谱,用作图软件QTLMapper1．0定位与种子活力相关的QTL。共检测到13个主效应QTL,这些QTL对性状的贡献率为2．9％～12．7％,平均贡献率为6．2％。同时检测到18对贡献率≥5％的互作位点,其贡献率为5．1％～11．8％,平均贡献率为6．9％,比检测到的主效应QTL的平均贡献率稍大。种子活力相关性状的大多数主效应和互作QTL成串分布于少数几个染色体区段(Chromosome Regions,CRs),并且成串分布在同一染色体区段的QTL效应的方向总是一致,该结果与这些性状在表型上的正相关相一致。若将成串分布有3个及3个以上种子活力相关性状QTL的CRs视为与种子活力高度相关的CRs,则共检测到7个上述与种子活力高度相关的CRs,分别分布在水稻12条染色体中的7条染色体上。根据所含QTL的种类(主效应QTL或／和上位性QTL)可将这些CRs分成以下3种：1)M-CRs：只含有主效应QTL,如CR^sv-7;2)E-CRs：所含位点没有主效应,但与其他位点发生互作,如CR^sv-1、CR^sv-6和CR^sv-12;3)ME-CRs：既含有主效应QTL、也含有与其他位点产生互作的互作位点,如CR^sv-2、CR^sv-5和CR^sv-8。另外还发现,有的CR上的位点同时与多个不同CR上的位点互作,影响种子活力的相关性状。与前入的研究结果相比较,发现有些与种子活力高度相关的CR可在不同研究者所用的不同定位群体中被检测到,而有的CR只在特定的定位群体中被检测到。由此表明,水稻种子活力具有丰富的遗传多样性和复杂的遗传基础,其主效QTL和互作位点可能基于遗传背景的不同而相互转化。     

Identification of QTLs with Additive,Epistatic, and QTL × Seed Maturity Interaction Effects for Seed Vigor in Rice

Seed maturity is a critical process of seed vigor establishment. In this study, one rice population of recombinant inbred lines (RILs) was used to determine the genetic characteristics of seed vigor, including the germination potential (GP), germination rate (GR), germination index (GI), and time for 50 % of germination (T₅₀), at 4, 5, and 6 weeks after heading in 2 years. Significant differences of seed vigor were observed among two parents and RIL population; the heritability of four traits was more than 90 % at three maturity stages. A total of 19 additive and 2 epistatic quantitative trait loci (QTL) for seed vigor were identified using QTL Cartographer and QTLNetwork program, respectively, in 2012, while 16 simple sequence repeat (SSR) markers associated with seed vigor were detected using bulked segregant analysis (BSA) in 2013. The phenotypic variation explained by each additive, epistatic QTL, and QTL × seed maturity interaction ranged from 9.19 to 22.94 %, 7.23 to 7.75 %, and 0.05 to 0.63 %, respectively. Ten additive QTLs were stably expressed in 2 years which might play important roles in establishment of seed vigor in different environments. By comparing chromosomal positions of ten stably expressed additive QTLs with those previously identified, they might be true QTLs for seed vigor; the regions of QTLs for seed vigor are likely to coincide with QTLs for seed dormancy, seed reserve mobilization, low-temperature germinability, and seedling growth. Using four selected RILs, three cross-combinations were predicted to improve seed vigor; 9 to 10 elite alleles could be pyramided by each combination. The selected RILs and the identified QTLs might be applicable for the improvement of seed vigor by marker-assisted selection (MAS) in rice.     

水稻株高构成因素的QTL剖析

利用水稻籼粳杂交 (圭 6 30× 0 2 42 8) F1 的花药离体培养建立的一个含 81个 DH家系的作图群体 ,对水稻株高构成因素 (穗长、第 1节间长、……、第 5节间长 )进行基因定位。DH群体中株高构成因素均呈正态分布。相邻的构成因素间呈极显著的正相关 ,而相距较远的构成因素间的相关较弱或不显著。采用 QTL(Quantitative trait lo-cus)分析 ,定位了影响株高构成因素的 6个 QTL:qtl7同时影响穗长和第 1、2、3节间长 ,qtl1 和 qtl2 同时影响第 4和第 5节间长 ,qtl1 0 a和 qtl1 0 b仅影响第 1节间长 ,qtl3 仅影响第 3节间长。采用 QTL 互作分析 ,检测到 19对显著的互作 ,每个构成因素受 2个或 2个以上的 QTL 互作对的影响。并且还发现 ,同一个 QTL 互作对可能影响不同的性状 ,以及一个 QTL 可以分别与不同的 QTL 产生互作而影响同一个性状或影响不同的性状 ,但总的看来 ,加性效应是主要的。这些结果揭示了株高构成因素间相关的遗传基础 ,在水稻育种中运用这些 QTL 将有助于对株高 ,以及对穗长和上部节间长度进行精细的遗传调控。     

Dynamic quantitative trait locus analysis of seed dormancy at three development stages in rice

In this study, a rice population of recombinant inbred lines (RILs) was used to determine the genetic characteristics of seed dormancy (SD) at 4 (early), 5 (middle) and 6 (late) weeks after heading stages. Dynamic analysis showed that the indica IR28 variety tended to have deeper dormancy than the japonica Daguandao at the middle and late development stages. The level of SD decreased with the process of seed development. The significant interaction between heading date (HD) and SD occurred only in those seeds collected at the early development stage. A total of nine additive quantitative trait loci (QTLs) and eight epistatic QTLs for SD were identified at three seed development stages. Of them, one additive and four epistatic QTLs were identified for the early stage, six additive and one epistatic QTL for the middle stage and two additive and three epistatic QTLs for the late stage. The phenotypic variation explained by each additive and epistatic QTL ranged from 5.8 to 30.6 % and from 3.8 to 13.1 %, respectively. Compared with the additive QTLs, epistatic interactions were much more important for SD at the early and late development stages. Two major additive QTLs, qSD3.1 and qSD4.1, were identified; each QTL could explain more than 20 % of the total phenotypic variance and each dormancy-enhancing allele could decrease the germination percentage by about 10 %. By comparing the chromosomal positions of these additive QTLs with those previously identified, five additive QTLs, qSD1.2, qSD2.1, qSD3.2, qSD4.1 and qSD9.1, might represent novel genes. One QTL identified here, qHD1, and nine QTLs identified in previous studies for HD were co-located with our QTLs for SD, which indicated that the significant correlation between SD and HD might be due to the linkage of QTLs for SD and HD. Four RILs with deep dormancy at development stages but non-dormancy after post-ripening under different germination conditions were selected. Using the selected RILs, three cross combinations of SD for the development of RIL populations were predicted. The selected RILs and the identified QTLs might be applicable for the improvement of pre-harvest sprouting tolerance by marker-assisted selection in rice.