粳稻粒形性状的数量性状基因座检测

 【目的】通过对粳稻粒形性状的QTL检测,为粳稻粒形性状相关QTL的精细定位和分子标记辅助选择育种提供理论依据。【方法】利用大粒粳稻DL115与小粒粳稻XL005杂交获得的F2代200个个体为作图群体,在北京进行稻谷粒长、粒宽、粒厚、长宽比、千粒重等粒形性状的鉴定。采用复合区间作图法,利用SSR标记对上述粒形性状进行数量性状基因座检测。【结果】上述粒形性状在F2群体均呈正态连续分布,表现为由多基因控制的数量性状。共检测到与粒形性状相关的QTL 16个,分布于第2、3、5和12染色体上。其中qGL3a、qGW2、qGW5、qGT2、qRLW2、qRLW3、qGWT2和qGWT3对表型变异的贡献率分别为15.42%、40.89%、13.54%、33.43%、13.82%、13.61%、12.51%和10.1%,为主效QTL。其中,qGW2、qGT2、qRLW2和qGWT2均位于第2染色体上的RM12776－RM324 区间。在所检测到的16个QTL中,4个QTL的增效等位基因来源于小粒亲本XL005,而其余QTL的增效等位基因均来源于大粒亲本DL115。基因作用方式主要表现为加性或部分显性。【结论】粳稻粒形性状是由多基因控制的数量性状。第2染色体RM12776－RM324区间是分别与粒宽、粒厚、长宽比和千粒重相关的4个主效QTL的共同标记区间,与其相邻的2个标记（RM12776和RM324）应在分子标记辅助选择育种中探讨其利用价值。大粒亲本对稻谷粒长、粒宽、粒厚和千粒重等性状的增效作用显著。     

水稻粒厚主效位点qGT8精细定位和候选基因分析

【目的】在已鉴定的稻谷粒长、粒宽和粒厚QTL的基础上,对控制粒厚的主效QTL进行精细定位和候选基因分析,以解析川106B（C-106B）细长粒形的遗传基础,为进一步通过分子技术改良其产量水平提供科学依据。【方法】以细长粒形的优质籼稻保持系川106B与籽粒较宽厚的籼稻保持系川345B（C-345B）杂交,构建包含182个单株的F2群体,采用QTL Catographer v2.5软件基于复合区间作图法发掘与稻谷粒形性状相关的QTL;进一步从BC₃F₂群体筛选隐性单株（稻谷厚度较薄）对粒厚主效QTL（qGT8）进行精细定位,并对候选基因进行测序和荧光定量PCR分析。分别构建qGT8位点携带川106B等位基因的近等基因系（NIL-gt8^C-106B）和携带川345B等位基因的近等基因系（NIL-GT8^C-345B）并调查其稻米外观品质及产量性状。【结果】川106B和川345B的粒长、粒宽和粒厚表型存在显著差异。利用F₂群体检测到2个粒长QTL、3个粒宽QTL和3个粒厚QTL,其中,位于第7染色体区间RM21892-RM3589的粒长主效QTL（qGL7）可解释粒长变异的68.23%,川106B等位基因在该位点可增加粒长0.47 mm。控制稻谷粒宽和粒厚的主效QTL（qGW8和qGT8）位于第8染色体上相同区间RM6070-RM447,分别解释相应表型变异的26.48%和34.89%,增加粒宽或粒厚的等位基因均来自于川345B。利用1 732个BC₃F₂隐性单株,将粒厚主效位点qGT8精细定位在标记SG930和SG950间的11.2 kb区段,该区段仅包含1个注释基因LOC_os08g41940（OsSPL16）。对该基因测序分析发现,川106B和川345B在起始密码子ATG上游2 kb区段存在7个差异位点,在编码区有5个多态性位点,其中,川106B在第3外显子插入2 bp（c.1006_1007 插入CT）引起移码突变,且位于qGT8的OsmiR156结合位点,推测为川106B籽粒厚度变薄、宽度变细的关键位点。实时荧光定量PCR分析发现,qGT8在幼穗中表达量较高,且在川106B和川345B中的表达方式相似,表达量在1-8 cm长幼穗发育时期随幼穗发育逐渐增加,8 cm时达到最高,之后随幼穗发育逐渐降低,但2个亲本在各时期的表达水平存在差异。近等基因系NIL-GT8^C-345B的粒厚、粒宽、千粒重、单株产量和垩白粒率显著高于NIL-gt8^C-106B,而粒长、透明度、株高、单株有效穗数、穗长、每穗实粒数、结实率和播抽期与NIL-gt8^C-106B相当。【结论】控制粒长的主效QTL（qGL7）位于第7染色体区间RM21892-RM3589,控制粒宽和粒厚的主效QTL位于第8染色体的相同区间RM6070-RM447。粒厚主效QTL（qGT8）被精细定位在仅包含GW8的片段上,是控制粒形和产量的关键基因,但在近等基因系中高粒重与高垩白紧密连锁,表明该位点存在高产与外观品质改良的矛盾。     

水、旱稻氮高效QTL定位及其表达的遗传背景效应研究

【目的】挖掘不同来源水、旱稻亲本的氮高效优良等位变异,研究氮高效QTL表达的遗传背景效应,为水稻氮高效QTL的精细定位和分子标记辅助选择育种提供理论依据。【方法】以旱稻IAPAR-9分别与水稻辽盐241和秋光杂交而创制的2个F7粳粳交重组自交系群体为试验材料,进行了水稻全生育期氮素利用率及其相关性状的QTL定位分析。【结果】在"IAPAR-9/辽盐241"重组自交系群体中检测出31个氮素利用率相关性状的QTL,分布于除第6、第7和第10染色体外的9条染色体上,氮素利用率相关QTL成簇分布区间有9个;在"IAPAR-9/秋光"重组自交系群体中检测出33个氮素利用率相关性状的QTL,分布于除第4和第10染色体外的10条染色体上,氮素利用率相关QTL成簇分布区间有7个。【结论】氮素利用率相关性状QTL的表达,受遗传背景影响较大。2个群体均检测到的氮素利用率相关性状QTL的成簇分布区间,即第2染色体上的RM3421—RM5404区间以及第8染色体上RM8264所在的相邻区间,可能对水稻氮高效分子标记辅助选择育种有重要利用价值。     

水稻第6染色体短臂产量性状QTL簇的分解

【目的】将水稻第6染色体短臂上产量性状QTL分解到更小的区间中。【方法】从珍汕97B/密阳46重组自交系群体筛选到针对第6染色体短臂RM587-RM19784区间的剩余杂合体,衍生了一个由221个株系组成的F2:3群体,种植于海南和浙江两地,考察每株穗数、每穗实粒数、每穗总粒数、千粒重、结实率和单株产量,建立SSR标记连锁图,应用Windows QTL Cartographer 2.5检测QTL。【结果】在所分析的6个性状中,除穗数外在第6染色体短臂上的目标区间均检测到QTL,分别座落于目标区域中3个以上的不同区间中,单个QTL对群体性状表型变异的贡献率为6.3%～35.2%;控制产量构成因子的QTL基本以加性作用为主,但3个单株产量QTL的显性度分别为1.65、0.84和0.42。【结论】目标区间存在3个以上的产量性状QTL,且同一区间控制不同性状的QTL、不同区间控制同一个性状的QTL在遗传作用模式、效应方向和效应大小上存在一定差异。     

水稻遗传图谱构建及粒形相关性状的QTL定位

[目的]构建水稻遗传连锁图谱,并对水稻粒形相关性状进行QTL分析,为水稻高效育种提供理论依据和育种材料.[方法]对具有极端粒形差异的两份水稻材料K1561和G1025进行杂交、自交获得F2分离群体,通过软件Map-maker/Exp 3.0构建水稻遗传连锁图谱,并利用软件QTLNetwork-2.0对2011年F2群体、2012年F2∶3家系群体的粒形相关性状数据进行相关性状的QTL定位.[结果]两个亲本的粒形性状指标差异明显,以千粒重相差最大;F2、F2∶3两个群体的相关粒形指标基本上呈连续分布状态且分布频率范围广.与F2单株相比,F2∶3家系的千粒重、粒长和粒宽的平均值更偏向于大粒亲本K1561.构建了含161对SSR标记的水稻遗传连锁图谱;共检测到18个粒形相关性状的QTL,分别分布于第1、2、3、7、9和12染色体上.其中,控制千粒重、粒长、粒宽和长宽比的QTL分别有7、5、5和1个,除qGL/GW12外,其他增效等位基因均来源于大粒亲本K1561.两个群体均能检测到的QTL有8个,分别为qTGW3、qTGW7、qTGW9.2、qTGW12、qG L1、qGL9、qGW12和qGL/GW12,其平均加性遗传力为6.04％、12.59％、6.29％、22.08％、4.86％、15.39％、22.12％和10.83％.[结论]定位获得3个效应值较大的新QTL位点qTGW12、qGL9和qGW12,为进一步定位并克隆这些粒形相关基因、阐明水稻产量和品质的控制机理提供了较好的遗传材料.     

水稻粒形性状的QTL分析

为了促进水稻粒形性状分子标记辅助选择育种研究,以籼稻二九南和粳稻龙稻5号杂交衍生的重组自交系群体为材料,对粒长、粒宽和粒厚3个粒形性状进行数量性状基因定位(Quantitative trait loci,QTL)分析。结果表明:采用完备区间作图法(ICIM),共检测到7个控制粒形性状的QTL,包括3个粒宽QTL,4个粒厚QTL,它们分布于第2、3、5、11和12号染色体上,其中4个主效QTL包括1个控制粒宽的qGW5a和3个控制粒厚的qGT2a、qGT11a以及qGT12a,但未检测到控制粒长的QTL位点。进一步分析表明,3个控制粒宽性状的QTL能解释28.44%的表型贡献率,单个表型贡献率为6.61%~13.81%;而4个控制粒厚性状的QTL能解释17.53%的表型贡献率,单个表型贡献率为7.32%~15.30%。     

Association mapping of quantitative trait loci for yield-related agronomic traits in rice(Oryza sativa L.)

High yield in rice mainly depends on large grain weight, ideal plant architecture and proper flowering time adapting to various geographic regions. To help achieve higher yield, phenotype variations of heading date(HD), plant architecture and grain shape in a panel of 416 rice accessions were investigated in this study. A total of 143 markers including 100 simple sequence repeat(SSR) markers and 43 gene-tagged markers were employed in association mapping to detect quantitative trait loci(QTL) responsible for these variations. Among the 7 subpopulations, POP5 in japonica group showed the largest values of HD and grain width(GW), but the smallest values of grain length(GL) and grain length to width ratio(GLW). Among the six indica groups, POP7 had the largest values of HD, GL, GLW, and 1 000-grain weight(TGW). A total of 27 QTLs were detected underlying these phenotypic variations in single year, while 12 of them could be detected in 2006 and 2007. GS3 marker was closely associated with GL, GW and GLW, and widely distributed in different groups. The starch synthesis related gene markers, SSI, SSIIa, SBE1, AGPL4, and ISA1, were linked to plant height(PH), panicle length(PL), flag leaf length(FLL), GW, and GLW. The SSR markers, RM267, RM340 and RM346, were linked to at least two traits. Therefore, these new markers will probably be used to improve rice grain yield or plant architecture when performing marker-assisted selection of proper alleles.     

Identification of long-grain chromosome segment substitution line Z744 and QTL analysis for agronomic traits in rice

Length of grain affects the appearance, quality, and yield of rice. A rice long-grain chromosome segment substitution line Z744, with Nipponbare as the recipient parent and Xihui 18 as the donor parent, was identified. Z744 contains a total of six substitution segments distributed on chromosomes(Chrs.) 1, 2, 6, 7, and 12, with an average substitution length of 2.72 Mb. The grain length, ratio of length to width, and 1 000-grain weight of Z744 were significantly higher than those in Nipponbare. The plant height, panicle number, and seed-set ratio in Z744 were significantly lower than those in Nipponbare, but they were still 78.7 cm, 13.5 per plant, and 86.49%, respectively. Furthermore, eight QTLs of different traits were identified in the secondary F2 population, constructed by Nipponbare and Z744 hybridization. The grain weight of Z744 was controlled by two synergistic QTLs(qGWT1 and q GWT7) and two subtractive QTLs(qGWT2 and qGWT6), respectively. The increase in the grain weight of Z744 was caused mainly by the increase in grain length. Two QTLs were detected, qGL1 and qGL7-3, which accounted for 25.54 and 15.58% of phenotypic variation, respectively. A Chi-square test showed that the long-grain number and the short-grain number were in accordance with the 3:1 separation ratio, which indicates that the long grain is dominant over the short-grain and Z744 was controlled mainly by the principal effect qGL1. These results offered a good basis for further fine mapping of qGL1 and further dissection of other QTLs into single-segment substitution lines.     

Validation of qGSIO,a quantitative trait locus for grain size on the long arm of chromosome 10 in rice (Oryza sativa L.)

Grain size is a major determinant of grain weight and a trait having important impact on grain quality in rice.The objective of this study is to detect QTLs for grain size in rice and identify important QTLs that have not been well characterized before.The QTL mapping was first performed using three recombinant inbred line populations derived from indica rice crosses Teqing/IRBB lines,Zhenshan 97/Milyang 46,Xieqingzao/Milyang 46.Fourteen QTLs for grain length and 10 QTLs for grain width were detected,including seven shared by two populations and 17 found in one population.Three of the seven common QTLs were found to coincide in position with those that have been cloned and the four others remained to be clarified.One of them,qGS10 located in the interval RM6100-RM228 on the long arm of chromosome 10,was validated using F_(2:3) populations and near isogenic lines derived from residual heterozygotes for the interval RM6100-RM228.The QTL was found to have a considerable effect on grain size and grain weight,and a small effect on grain number.This region was also previously detected for quality traits in rice in a number of studies,providing a good candidate for functional analysis and breeding utilization.     

利用染色体片段置换系定位水稻粒型QTL

水稻粒型是衡量稻米外观品质的重要指标之一,鉴定和定位水稻粒型QTL对开展水稻粒型分子育种具有重要意义.本研究以8个染色体片段置换系为材料,选用分布水稻12条染色体上的153个SSR标记检测染色体片段置换系的置换片段,采用代换作图法对控制水稻粒型的3个主效QTL进行定位.结果表明:153个SSR标记中有104个标记在亲本间具有多态性,多态率为68.0%;8个染色体片段置换系在第3和第5染色体分别有6个和2个置换片段,置换片段长度分别为14.8 cM、16.6 cM、 15.5 cM、18.9 cM、29.1 cM、35.0 cM、17.9 cM 和17.0 cM,平均长度为20.6 cM;8个置换片段上共鉴定出3个粒型QTL,控制粒长的qGL-3-1 和qGL-3-2分别被界定在水稻第3染色体RM5551与RM6832及RM6832与RM3513之间,遗传距离分别为14.8 cM和5.3 cM的范围内,控制粒宽的qGW-5被界定在水稻第5染色体RM267与RM169之间遗传距离约11.7 cM的范围内.利用染色体片段置换系能准确地定位水稻粒型QTL,qGL-3-1、qGL-3-2和qGW-5的鉴定和初步定位为其进一步精细定位及分子标记辅助选择奠定了基础.     

Dissection of QTLs for Yield Traits on the Short Arm of Rice Chromosome 6

This study was undertaken to dissect quantitative trait loci （QTLs） controlling yield traits on the short arm of rice chromosome 6. A residual heterozygous line that carries a heterozygous segment extending from RM587 to RM19784 on the short arm of rice chromosome 6 was selected from an F7 population of the indica rice cross Zhenshan 97B/Milyang 46. An F2：3 population consisting of 221 lines was derived and grown in two trial sites. Six yield traits including number of panicles per plant, number of filled grains per panicle, total number of spikelets per panicle, spikelet fertility, 1 000-grain weight, and grain yield per plant were measured. An SSR marker linkage map was constructed and employed to determine QTLs for yield traits with Windows QTL Cartographer 2.5. QTLs were detected in the target interval for all the traits analyzed except NP, with phenotypic variance explained by a single QTL ranging between 6.3% and 35.2%. Most of the QTLs for yield components acted as additive QTLs, while the three QTLs for grain yield had dominance degrees of 1.65, 0.84, and -0.42, respectively. It was indicated that three or more QTLs for yield traits were located in the target region. The genetic action mode, the direction of the QTL effect, and the magnitude of the QTL effect varied among different QTLs for a given trait, and among QTLs for different traits that were located in the same interval.     

TD70/Kasalath RIL群体定位水稻穗部主要性状的QTL(英文)

利用穗部性状存在明显差异的粳稻TD70和籼稻品种Kasalath杂交,经单粒传法获得的240个重组自交系(RIL)为作图群体,分别于2010和2011年对穗长每穗总粒数和着粒密度进行鉴定,用完备区间作图法,以均匀分布于12条染色体的141个SSR标记对粒型性状进行QTL检测结果表明,共检测到3个性状的QTL23个,其中控制穗长的5个QTL每穗总粒数的8个QTL着粒密度的10个QTL,分布在第2、3、4、6、7、8、9和10染色体上,LOD值范围为2.5~9.3,单个QTL的贡献率介于4.0%~20.8%之间第2染色体的RM5699-RM424第3染色体的RM489-RM1278第4染色体的RM3367-RM1018和第6染色体的RM3343-RM412区间,都检测到同时影响每穗总粒数着粒密度的QTL,2年均被检测到的QTL共有6个QTL,分别是控制穗长的qPL3每穗总粒数的qTSP4、qTSP6-2、qTSP7着粒密度的qGD3-2、qGD7其中qPL3qTSP6-2qGD3-2和qGD7为主效QTL除穗长性状5个位点均有报道外,其余2个性状中均发现新的位点,共有16个QTL可能是新的位点,单个QTL贡献率为4.0%~9.5%本研究为进一步精细定位或克隆这些粒型QTL奠定了基础。     

Quantitative Trait Loci for Panicle Size and Grain Yield Detected in Interval RM111-RM19 784 on the Short Arm of Rice Chromosome 6

A rice residual heterozygous line （RHL） carrying a heterozygous segment extending from RM111 to RM19784 on the short arm of rice chromosome 6 was selected from a RHL-derived population used previously. The resultant F2：3 population was used to detect quantitative trait loci （QTLs） for three yield traits, the number of spikelets per panicle （NSP）, the number of grains per panicle （NGP） and grain yield per plant （GY）. Two QTLs for NSP, one QTL for NGP and one QTL for GY were detected, all of which were partially dominant and had the enhancing alleles from the maternal line Zhenshan 97B. Analysis based on the genotypic groups of the markers closely linked to the two QTLs for NSP indicated that they did not interact with each other. Two F2 populations and two near isogenic line （NIL） sets segregating in two sub-regions of interval RM111-RM19784 were developed. The two QTLs for NSP were validated, of which one had major effect and was co-segregated with heading date gene Hdl, and the other had smaller effect and was located in an upper region linked to Hdl. The two regions also showed significant effects on the number of filled grain and grain yield, although the effect on the number of filled grain was less consistent.     

QTL mapping of grain appearance quality traits and grain weight using a recombinant inbred population in rice(Oryza sativa L.)

Grain appearance quality traits,measured as grain length(GL),grain width(GW),length to width ratio(LWR),grain thickness(GT) and the percentage of grain with chalkiness(PGWC),as well as 1 000-grain weight(TGW),are very important factors that contribute to rice grain quality and yield.To detect quantitative trait loci(QTLs) affecting these traits,we developed a set of recombinant inbred lines(RILs) derived from Gang46B(G46B) and K1075,a G46 B introgression line with lower PGWC.Based on a linkage map containing 33 simple sequence repeat(SSR) markers,a total of 15 additive QTLs governing six measured traits were identified on 4 chromosomes across two environments.Of these,the five major QTLs which controlled GW,LWR,GT,PGWC,and TGW,each explaining up to 44.30,55.29,62.30,30.94,and 28.78%of the variation,respectively,were found in the same interval of RM18004-RM18068 on chromosome 5.The G46 B alleles contributed to the increase in GW,GT and PGWC at all loci,as well as the increase in TGW at its major QTL locus.Significant interactions between additive QTL and the environment were found at most loci,in which the largest,accounting for15.06%of variation,was observed between qPGWC-5 and the environment.A total of 15 epistasis QTLs were detected for all the traits,and GL,GW and PGWC had significant epistasis QTLs based on environment interactions with minor effects.These results are valuable for future map-based cloning of the QTLs and the collaborative improvement of G46 B in grain appearance quality and yield.     

Detection of QTLs for Important Agronomic Traits and Analysis of Their Stabilities Using SSSLs in Rice

Single segment substitution lines （SSSLs） each with a single chromosome segment from a donor under the same genetic background as the recipient were developed in rice by advanced backcrossing and molecular marker-assisted selection. Using the SSSLs, the QTLs for the important agronomic traits in rice would be detected under different environmental conditions. Detection of the QTLs controlling 22 important traits in rice was done with 32 SSSLs by the randomized block design in 2-4 cropping seasons. 59 QTLs were detected and distributed on chromosomes 1, 2, 3, 4, 6, 7, 8, 10, and 11, of which 18 QTLs were detected more than twice. Only 30.5% of the QTLs were detected repeatedly in different cropping seasons. Most of the QTLs of important agronomic traits were of little additive effects and instability. The QTLs controlling the traits, such as grain weight, grain length, ratio of grain length to width, and heading date were relatively stable. The stable QTLs usually had larger additive effects and were less affected by environment. The QTLs for the important agronomic traits were detected using the SSSLs in rice with high resolution under different environmental conditions. The instability of the QTLs may be the basis of the variation of rice plants during growth and development. It would be the genetic basis for improving yield and quality in rice cultivars by farming methods.     

水稻芽期耐冷性QTL的分子定位

 以籼粳交密阳23号/吉冷1号的F2：3 代200个家系作为作图群体，构建了一张含有97个微卫星 （SSR）标记的分子连锁图谱。在5℃低温条件下，对F3家系进行芽期耐冷性鉴定，并利用SSR标记进行了芽期耐冷性数量性状位点（QTL）分析。研究结果表明，芽期耐冷性在F3家系群中呈单峰连续分布，表现为由多基因控制的数量性状；共检测到与芽期耐冷性有关的QTL 3个，分别位于第2、4 和7染色体上，对表型变异的贡献率范围为11.5%～20.5%。其中，位于第4染色体RM273～RM303的qCTBP4对表型变异的贡献率最大。     

籼稻不同定位群体的抽穗期和株高QTL比较研究

 【目的】通过分析控制不同定位群体水稻抽穗期、株高和产量性状表现的QTL,挖掘同时控制株高与产量性状且对抽穗期影响小的QTL区间,为水稻高产育种提供参考。【方法】以杂交稻恢复系密阳46作为共同父本,分别与保持系协青早B和珍汕97B配组,构建2个籼籼交重组自交系群体,在同一地点多年种植,对不同群体抽穗期和株高相关的QTL定位结果进行比较。【结果】共定位到12个抽穗期QTL和11个株高QTL,其中2个抽穗期QTL在2个群体中都能检测到,分别位于第6染色体短臂和第7染色体长臂近着丝粒区域。通过与前期相同群体产量性状QTL定位结果比较,发现6个多效性区间,其中,1个同时控制抽穗期、株高和产量性状,3个同时控制抽穗期和产量性状,2个同时控制株高和产量性状。【结论】相对于共同的父本密阳46,水稻矮败型保持系协青早B与野败型保持系珍汕97B对抽穗期和株高的遗传控制存在较大差异,并以株高更为明显。第2染色体长臂RM6—RM240的QTL作用较稳定,对株高和产量性状作用方向一致,且对抽穗期无显著影响,对于通过“矮中求高”实现水稻高产育种具有重要的应用价值。     

华南杂交稻亲本米质性状配合力的SSR标记鉴定

[目的]筛选与华南地区杂交稻亲本米质性状配合力连锁的分子标记,为华南地区杂交稻亲本米质改良和选配提供理论指导.[方法]利用SSR标记技术,结合不完全双列杂交法,对华南地区18个杂交稻亲本配制的61个F1进行亲本米质性状相关性及配合力分子标记鉴定.[结果]从糙米率、米粒长和米粒长宽比3个性状来看,不育系和恢复系对F1的相关系数相近;垩白粒率、垩白度、碱消值和直链淀粉含量等性状,恢复系与F1的相关系数则显著大于不育系,同时双亲间遗传距离与F1的相关系数也相对较高.经标记筛选获得了与这些性状极显著相关的17个亲本SSR分子标记,其中,直链淀粉含量6个,即RM5、RM250、RM274、RM549、RM336和RM427;碱消值5个,即RM236、RM18、RM274、RM336和RM427;垩白粒率两个,即RM5和RM276;糙米率、精米率、垩白度及胶稠度各1个,依次为RM274、RM246、RM276、RM549.[结论]筛选的SSR标记可以直接用于华南杂交稻的米质预测及亲本配合力分子辅助育种改良.     

基于SSSL的水稻重要性状QTL的鉴定及稳定性分析

【目的】单片段代换系（SSSL）是通过高代回交和分子标记辅助选择构建的，只含有来自供体亲本的一个染色体片段，遗传背景与受体亲本相同的品系。本研究的目的是利用SSSL检测不同环境条件下水稻重要性状的QTL。【方法】以32个SSSL为材料，随机区组试验设计，在2～4个季节中对水稻22个重要性状的QTL进行分析。【结果】共鉴定出59个QTL，分布于第1、2、3、4、6、7、8、10和11号染色体上。其中的18个QTL能够在2次以上重复检出，稳定性较好的QTL占检出QTL的30.5%，大多数农艺性状的QTL效应较小、稳定性较差。不同的性状，QTL稳定性不同，千粒重、粒长、谷粒长宽比、抽穗天数等性状的QTL较稳定。稳定性好的QTL，不仅具有较大的加性效应，而且受环境影响较小。【结论】利用单片段代换系可以有效地对水稻重要性状的QTL进行多年多季的稳定性分析。水稻大多数重要农艺性状QTL的不稳定性，反映了水稻生长发育过程的可塑性，可能是通过栽培措施使水稻品种获得高产优质的重要遗传基础。     

利用2个相关群体定位和比较水稻株高与抽穗期QTL

利用一个共同亲本构建的2个重组自交系群体对控制水稻株高和抽穗期进行基因定位和比较分析。结果表明:2个群体共定位到11个控制抽穗期的数量性状位点(QTLs)和11个株高QTLs。控制抽穗期的主效QTL在珍汕97/南洋占群体内位于第7染色体RM500-RM445标记之间;在珍汕97/德陇208群体内定位于第7染色体RMRG4499-RM445标记之间。而控制株高的主效QTL在2个群体中分别定位于第1染色体RM472-RM104之间和第7染色体MRG4499-RM445之间。比较定位结果发现,抽穗期主效QTL在2个群体内都被定位于第7染色体中部位置并且有共同标记RM445,很有可能是同一个基因。说明抽穗期是由主效QTL控制的数量性状,遗传稳定。株高主效QTL在珍汕97/南洋占群体内被定位于第1染色体接近末端标记RM104附近。在珍汕97/德陇208群体内则定位于第7染色体,与该群体控制抽穗期QTL共享RM445标记。