The first intraspecific genetic linkage maps of wintersweet [Chimonanthus praecox (L.) Link] based on AFLP and ISSR markers

Wintersweet [Chimonanthus praecox (L.) Link] (n = 11), a dichogamous species, is a famous traditional fragrant flower plant in China. We used AFLPs and ISSR to construct a genetic linkage map on a pseudo-F₂ population of wintersweet derived from a cross between the individuals H4 and H29. A total of 370 polymorphism markers was generated from 12 AFLP primer combinations and 9 ISSR primers. Two separate female and male maps were constructed using 84 female-specific and 51 male-specific testcross markers, respectively. The maternal H4 map included 80 markers ordered in 12 linkage groups; while the paternal H29 map had 47 markers in 8 linkage groups. At a minimum logarithm of the odds (LOD) score of 3.0 and maximum map distance of 50 cM, the female map covered 2417.8 cM, with an average distance of 25.61 cM and maximum map distance of 48.2 cM between two loci. In contrast, the male map covered 1184.2 cM, with an average distance of 25.7 cM and maximum map distance of 49.0 cM between two loci. These genetic maps will serve as a framework for mapping QTLs and provide basic information for future molecular breeding studies.     

QTL analysis and regression model for estimating fruit setting in young Citrus trees based on molecular markers

This study was conducted to assess the genetic basis and develop a regression model for a QTL trait, fruit setting of a full sib population of 164 hybrids obtained between ‘Clementine’ mandarin (Citrus reticulata Blanco ‘Clementine) and ‘Orlando’ tangelo’ (Citrus paradisi Macf. ‘Duncan’ × C. reticulata Blanco ‘Dancy’). Fruit setting of a 164 full sib population field-planted in 2007 was evaluated by visual counting of fruits in 2008, 2009, and 2010. We estimated linkage groups and effects of QTLs by using MapQTL5. Based on interval mapping, seven linkage groups of the maternal and eight linkage groups of the paternal maps harboured QTLs of the fruits setting, covering a total 300 of 1744 cM Citrus map. Only three segments were associated with all three-year data (one in ‘Clementine’ and two in ‘Orlando’ map) spanning 60 cM of 1744 cM of Citrus linkage map. Twenty-seven (17%) and 13 (8%) hybrids consistently produced less than 5 fruits and the highest number of fruits (≥50) in their 2nd, 3rd, and 4th ages. Based on BACKWARD elimination procedure of PROC REG option nested in SAS program, regression models constructed for 2008, 2009, and 2010s fruit setting explained 35, 81, and 38% of the total phenotypic variation (R²) observed in the 164 full-sib hybrids, respectively (P ≤ 0.05). This study indicated that early fruit setting was a complex trait affected by many QTLs and the regression model developed in this study might be used to predict performances of hybrids with similar genetic background.     

黄瓜种子大小遗传分析与QTL 定位

 以种子大小差异显著的黄瓜野生变种‘PI183967’（Cucumis sativus var. hardwickii）和栽培 品种‘新泰密刺’选系‘931’为亲本,通过6 世代混合模型分析方法,研究种子长度和宽度的遗传规律, 并利用包含160 个株系的F9 代重组自交系群体,构建SSR 分子遗传图谱,完成种子长度、宽度及百粒质 量的QTL 染色体定位。结果表明：（1）种子长度与宽度在正、反交6 世代群体中均符合C–0 遗传模型 （加性-显性-上位性多基因遗传模型）,且以多基因加性效应为主。（2）构建的永久SSR 遗传图谱,包 含149 个SSR 标记,9 个连锁群,覆盖基因组长度389.2 cM,平均标记间距为2.61 cM。（3）2012 年春季 与2013 年春季共检测到14 个与种子长度、宽度和百粒质量相关的QTL,分布在Chr.2、Chr.3、Chr.4、 Chr.5、Chr.6 染色体上,LOD 值介于2.59 ~ 9.39 之间,可解释7.4% ~ 28.3%的表型变异率,贡献率 ≥ 10.0% 的QTL 位点6 个,占QTL 总数的42.9 %,可在两年中重复检测出的QTL 位点3 个,占QTL 总数的21.5%。     

利用重组自交系群体构建番茄AFLP 遗传连锁图谱

 以普通栽培番茄（Solanum lycopersicum）99165-30为母本,野生多毛番茄（Solanum habrochaites）LA1777为父本进行杂交,通过单粒传得到了含有80个F_5︰6家系的重组自交系分离群体,利用荧光AFLP分子标记技术构建番茄分子遗传连锁图谱。AFLP标记采用MseⅠ和EcoRⅠ两种内切酶及荧光标记（IRD-700或IRD-800）的E + 3和非荧光标记的M + 3引物组合进行选择性扩增,扩增结果经95 ℃预变性后在6%变性聚丙烯酰胺凝胶上电泳2.5 h,运用LICOR 公司的NEN Global Edition IR² DNA Analyzer（Model 5200 LI-COR Biosciences,Lincoln,NE）荧光扫描检测DNA多态性。对RILs群体中产生分离的274个AFLP标记运用JoinMap 3.0软件分析,得到一张番茄分子遗传连锁图谱,图谱总长度为662 cM,共包括18个主要连锁群,125个多态性分子标记。每条连锁群上的标记数在3 ~ 22个之间,连锁群的长度在14.0 ~ 58.0 cM的范围内,平均图距在 2.27 ~ 13.3 cM。总平均距离5.3 cM,本研究中构建的番茄永久遗传图谱,为番茄分子辅助育种及重要农艺性状的定位奠定了基础。     

利用辣椒种间F2和F2:3两个群体进行其主要农艺性状QTL分析

以一年生辣椒（Capsicum annuum）材料‘V06C1720’为母本,灌木辣椒（C. frutescens）材料‘H101’为父本,建立包含180个单株的种间F2作图群体,应用SSR和SRAP标记技术构建了共278个标记位点的17个连锁群遗传图谱,图谱全长1 282.10 cM,标记平均间距为4.61 cM。利用QTLNetwork 2.0软件和 F2、F2:3表型数据,对辣椒15个主要农艺性状进行了QTL分析,在第1、2、3、4、6、7、10、12、13、14、15和16连锁群上共检测到48个加性QTL和11对上位性QTL,可分别解释5.18% ~ 40.33%和4.09% ~ 13.56%的表型变异。变异率大于10.00%的主效加性QTL有33个,占总数的68.75%;来自灌木辣椒‘H101’的增效等位加性QTL位点有29个,占总数的60.42%。株高、主茎高、果长、果径、单果质量、果形和果实辣味等7个性状的9个加性QTL在两个群体中同时被检出,这些在不同环境及不同遗传背景下能够稳定存在的QTL可为辣椒农艺性状分子标记辅助选择育种、QTL精细定位及克隆提供有价值的参考。     

甜瓜重组自交系群体SSR遗传图谱构建及纯雌性基因定位

 以甜瓜（Cucumis melo L.）纯雌株厚皮甜瓜品系WI998为母本,雌雄异花同株薄皮甜瓜品系3-2-2为父本杂交,通过单粒传得到了含有185个F6︰7家系的重组自交系分离群体,构建SSR分子遗传图谱。1 219对SSR引物在亲本间有多态性的为215对,多态率17.6%,构建的图谱共包含210个SSR标记,分属18个连锁群,覆盖基因组长度为937.1 cM,标记间平均距离为4.4 cM。将与性别表达密切相关的纯雌性基因（g）定位到了第1连锁群上,其两侧标记为NR3和MU8294_1,与g基因的遗传间距分别为1.2 cM和2.6 cM。     

梨果实相关性状QTL定位分析

以‘红茄梨’（Pyrus communis L.‘Red Clapp Favorite’）和‘晚秀梨’（P. pyrifolia Nakai‘Mansoo’）杂交F₁代中已结果的81株单株为试材,利用81株单株的SSR分型数据进行连锁分析,构建了包含187个SSR标记,分布在18个连锁群上的遗传连锁图谱。图谱总长964.82 cM,标记平均间距5.16 cM,与之前利用该群体165株单株为材料构建的双亲整合图谱比较,86.59%的标记在连锁群中的排列顺序一致。利用MapQTL5.0软件,对果实表型性状进行QTL定位和分析,最终检测到与果实单果质量、纵径和横径连锁的4个QTL位点,都位于LG11,离最近分子标记的遗传距离为1.00 ~ 2.00 cM。进一步对检测出的果实大小QTL位点距离最近的标记基因型与表型比对分析,发现其符合度在72.5% ~ 82.5%。     

桃遗传图谱的构建及两个花性状的分子标记

 以桃‘红垂枝’与其近缘种山桃‘白花山碧桃’杂交的52株F1群体为试材,采用SSR、AFLP和SRAP分子标记进行遗传分析。筛选扩增稳定且多态性丰富的38对SSR引物、61对AFLP引物和38对SRAP引物进行群体分离分析,获得符合1:1分离的标记441个,亲本为双杂合位点的标记52个。应用Mapmaker分析软件将符合1:1分离的标记和雌蕊发育性状一起构建了包含11个连锁群的遗传图谱,该图谱共206个标记（18个 SSR,126个 AFLP、61个SRAP和1个形态学标记）,全长1193.2 cM。每个连锁群的平均长度为108.5 cM,标记间平均图距为5.8 cM。根据18个SSR标记与T×E参考图谱比对,本试验中的11个连锁群对应于参考图谱的G1至G8,标记的线性符合度较好。雌蕊发育性状标记定位在第1连锁群,对应于1号染色体。应用Mapmaker分析软件将亲本为双杂合位点标记和花单瓣/重瓣性状一起分析,获得1个新单瓣/重瓣基因的2个AFLP标记。     

辣椒种内遗传图谱的构建及主要农艺性状的QTL分析

以一年生辣椒（Capsicum annuum L.）‘Perennial’、‘83-58’为亲本构建的包含128个株系的F6代重组自交系为作图群体,构建了一个包含有18个连锁群的遗传图谱。该遗传图谱共有131个标记,其中SSR标记105个,CAPS标记23个,SCAR标记1个,果实辣味（pun）和果柄着生方向（up）2个形态标记。该图谱全长633.71 cM,标记间的平均距离为4.8 cM,连锁群的长度为7.07 ~ 75.16 cM,平均长度为35.21 cM,每个连锁群上的标记数为3 ~ 17个。对群体进行10个主要农艺性状调查,利用基于完备区间作图方法（Inclusive Composite Interval Mapping）的QTL IciMapping V3.2软件（http：//www. isbreeding. net/）选择加性效应模型ICIM-ADD进行QTL定位,在重组自交系（RIL）群体中共检测到株高、伸展度、始花节位、叶长、叶宽、侧枝长度、果形、果形指数、心室数和果实横径等10个性状的20个QTL位点。     

Molecular characterization and analysis of somaclonal variation in chrysanthemum cultivars using RAPD markers

Molecular characterization using RAPD analysis was carried out in eight cut flowers and two pot plant cultivars of chrysanthemum. Three of them (‘Refocus’, ‘Red Reagan’, and ‘Sheena Select’) were established in vitro and the occurrence of somaclonal variation was studied using the same molecular technique. Two induction media (MS + 0.1 mg l⁻¹ NAA + 0.1 mg l⁻¹ BA, and MS + 2.0 mg l⁻¹ IAA + 0.5 mg l⁻¹ Kinetin), and two proliferation media (MS + 0.1 mg l⁻¹ NAA + 0.2 mg l⁻¹ BA, and MS + 4.0 mg l⁻¹ IAA + 2.0 mg l⁻¹ Kinetin) were employed in order to evaluate the effect of the medium composition in the shoots’ stability. Likewise, the effect of the culture age was considered in assessing genetic stability. Monthly subcultures were carried out, identifying the origin and history of the shoots, throughout a nine-month proliferation period followed by acclimatization. Molecular markers were obtained in every subculture cycle and from the acclimatized plants. Only one shoot from the 7th subculture of the cultivar ‘Refocus’ showed a different band pattern. The use of RAPD for chrysanthemum cultivar characterization and somaclonal variation detection is discussed.     

二倍体马铃薯分子连锁图谱的构建

利用二倍体马铃薯亲本08675-21与09901-01及其125份杂交一代无性系进行AFLP分析, 按亲本来源构建与24条染色体对应的AFLP分子连锁图谱, 母本图谱含有75个标记, 覆盖基因组全长512cM, 平均图距为6.83 cM; 父本图谱含有95个标记, 覆盖基因组全长578 cM, 平均图距为6.08 cM。     

A SCAR marker linked to the N gene for resistance to root knot nematodes (Meloidogyne spp.) in pepper (Capsicum annuum L.)

The root-knot nematodes (Meloidogyne spp.) are important nematode pests and cause serious diseases in pepper in the world. No molecular markers linked to the nematodes resistance N gene have been reported. In this paper, ‘Carolina Wonder’ (Capsicum annuum L.), a sweet pepper line resistant to root-knot nematode with N gene, ‘20080-5-29’ (C. annuum L.), an inbred line susceptible to root-knot nematode with good horticultural characteristics, and their F₂ progeny with 320 individuals were used as materials. Evaluation of resistance and susceptibility of parental lines, F₁ and F₂ progeny inoculated with root-knot nematodes (Meloidogyne incognita) were carried out. ‘Bulked segregant analysis’ method was used to search for polymorphic markers from 512 pairs of AFLP primers. Based on the assessment of resistance and susceptibility and polymorphism of the AFLP marker in F₂ population, the genetic linkage distance between the AFLP marker and the N gene was estimated. One AFLP marker E39/M41-339 was obtained and transferred to a SCAR marker amplifying a 315 bp DNA fragment linked to the N resistant allele and a 331 bp fragment linked to the N⁺ susceptible allele. The distance between the molecular marker and the nematodes resistance N gene is 6.3 cM. This research delivered a valuable tool for the marker assisted selection of nematodes resistance in pepper.     

成熟黄瓜果皮红色性状的遗传分析及其基因定位

 以黄瓜（Cucumis sativus L.）成熟瓜红色果皮自交系‘NCG127’（P₁）和成熟瓜黄色果皮自交系‘9930’（P₂）为试验材料构建F₂遗传群体,对成熟瓜红色果皮R基因进行遗传分析和基因定位研究。结果表明,黄瓜成熟瓜红色果皮性状由显性单基因控制,红色对黄色为显性。以256株F₂分离群体为试材,应用群体分离分析（BSA）法筛选得到与R基因连锁的20个多态性SSR标记,构建了R基因的分子标记连锁图谱,将R基因定位到黄瓜4号染色体上,物理距离为213.4 kb的区段内,两侧翼标记为UW019319和UW019203,与R遗传距离分别为0.8 cM和0.7 cM。生物信息学分析表明,该区段存在30个预测候选基因。     

利用芥蓝×青花菜DH群体构建AFLP连锁图谱

 利用青花菜(Brassica oleracea var. italica) 与芥蓝(Brassica oleracea var. alboglabra) 杂交后代双单倍体(DH) 群体为材料, 通过AFLP技术构建了一个甘蓝类作物较高密度的遗传连锁图谱。该图谱包括9个主要连锁群及2个小连锁群, 总图距801.5 cM, 含337个AFLP标记, 标记间平均距离为3.6 cM,为甘蓝类作物基因定位、比较基因组学及重要经济性状QTL分析提供了一个框架图谱。     

大白菜SSR锚定标记分子遗传图谱的构建

为了将已有的大白菜分子遗传图谱和国际上A基因组参考图谱对应起来,利用国际上发表的大白菜和甘蓝型油菜A基因组特异SSR标记作为锚定标记,以100个DH株系组成的群体为作图群体进行了分子遗传图谱的构建研究。利用双亲和F1对230个SSR标记和8个STS标记进行了筛选,共获得67个多态性分子标记。在此基础上整合了已有的263个AFLP标记、150个RAPD标记、17个SSR标记、3个SCAR标记、14个同工酶标记和1个形态标记,最终构建了一张由10个连锁群组成,包含了497个标记的大白菜高密度分子遗传图谱。该图谱覆盖基因组长度1 086.7 cM,标记间平均图距2.19 cM。此图谱上包含了已在A基因组参考图谱上定位的34个SSR标记和2个STS标记,分布于10个连锁群上,由此可将该图谱按A基因组参考图谱的连锁群进行命名,即A1~A10,并与10条染色体对应起来,A1~A10分别对应3、6、2、8、5、4、7、9、1、10号染色体。     

Phylogenetic analysis and genetic mapping of Chinese Hedychium using SRAP markers

In the present study, using the SRAP markers, we analyzed the interspecific phylogenetic relationship of 22 species of Chinese Hedychium to find out fine mapping population. Using the same technique, maps of two species selected by morphological characters were constructed. Phylogenetic analysis showed that 22 species were grouped into three clusters. The mapping parents selected were in one cluster, with a similarity coefficient of 0.31, which is lower than the mean value of 22 species. Two maps with medium-density were constructed. The maternal parent contained 139 loci and spanned 917.1 cM. These loci were distributed in 18 linkage groups. The paternal parent contained 203 loci and spanned 1386.8 cM, which spread over 23 linkage groups. Unfortunately, the number of loci with a segregation ratio of 3:1 was not sufficient for us to link two maps together. For parental selection, we suggested that the phylogenetic relationship as well as complements of characters should be considered. Moreover, our study showed that two species with similarity around or higher than the mean level tend to produce fine mapping population in Hedychium.     

辣椒白粉病抗性QTL 定位分析

以辣椒（Capsicum annuum）白粉病抗、感病亲本H3 和83-60 构建的包含142 个重组自交系的RIL（H3×83-60） F8 群体为试验材料,基于亲本重测序数据设计KASPar 引物,构建了包含16 个连锁群的辣椒遗传连锁图谱,总图距1 356.5 cM,标记间平均图距为4.69 cM。基于2016 年和2017 年重组自交系群体白粉病发病表型数据,获得了PMR6.1、PMR9.1、 PMR11.1、PMR11.2 和PMR5.1 等5 个白粉病抗性QTL 位点,其中PMR6.1、PMR9.1 在两年中均被检测到,表型贡献率在 10.8%～21.4% 之间。通过辣椒白粉病抗性QTL 定位,开发与白粉病抗性基因连锁的SNP 分子标记,对于辣椒抗病辅助育 种有重要参考价值。     

金叶弯刺蔷薇×山刺玫遗传连锁图谱的初步构建

以金叶弯刺蔷薇(Rosa beggeriana‘Aurea’,叶色突变材料)和山刺玫(R.davurica)为杂交亲本建立F1群体,利用AFLP和SSR分子标记进行遗传连锁图谱构建。结果表明:124个AFLP标记、25个SSR标记及1个形态标记定位于父、母本遗传连锁图谱的13个连锁群上,其中92个分子标记定位于金叶弯刺蔷薇7个连锁群,遗传距离覆盖度为607.2 c M,金叶突变性状被定位于第4连锁群;57个分子标记定位于山刺玫6个连锁群,遗传距离覆盖度为437.1 c M。两类分子标记的总作图效率达到69.6%。发生偏分离的分子标记数量为44个,偏分离率为29.5%。     

大白菜永久高密度分子遗传图谱的构建

 以大白菜高抗TuMV白心株系91-112和高感TuMV桔红心株系T12-19为亲本建立的小孢子培养DH系作为图谱构建群体, 构建了包含10 个连锁群、406 个标记位点的分子连锁图谱, 图谱总长度826.3 cM, 标记间的平均图距为2.0 cM, 连锁群数目和染色体数相等。每个连锁群上的标记数在7～111个之间, 连锁群的长度在26.4～156.1 cM的范围内, 平均图距在1.0～3.8 cM之间。该连锁图谱包括246个AFLP标记、135个RAPD标记、11个SSR标记和12个同工酶标记、1个SCAR标记和1个形态标记。     

甜瓜果实相关性状QTL 分析

以WI998（厚皮网纹、纯雌株甜瓜品系）为母本,以3-2-2（薄皮、雌雄异花同株甜瓜品系）
为父本进行杂交,通过单粒传得到了含有124 个F_6：7 家系的重组自交系群体,构建遗传连锁图谱。在608
对SSR 引物中筛选出亲本间有多态性的引物150 对,多态率为24.67%;该图谱包含17 个连锁群,覆盖基
因组长度为1 246.67 cM,标记间的平均距离为9.59 cM。应用复合区间作图法对甜瓜单果质量（Fw）、果
实硬度（Ff）、果实长度（Fl）、果形指数（Fsi）及果肉厚度（Ft）等性状进行QTL 分析,共检测到15 个
QTL,分别分布在第1、4、5、6、8、10、13、14、15、17 连锁群上,其中8 个QTL 贡献率超过10%,
位于第13 连锁群的QTL Ff13.2 贡献率最大, 为26.45%。标记ECM87 与Fsi8.2 位于同一位点, 标记
CM33 与Fsi15.1 紧密连锁,遗传距离为0.6 cM。