云南大理茶与福鼎大白茶种间杂交幼胚的组织培养及亲子鉴定

为解决茶树种间杂交不亲和及F1代生长发育困难等问题,在云南大理茶[Camellia taliensis(W.W.Smish)Melchior]与福鼎大白茶(C. Sinensis'Fuding Dabaicha')间进行了种间杂交试验,随机选取9个F1代杂种幼胚进行了组织培养,其余杂种田间播种,获得福鼎大白茶(♀)×云南大理茶(♂)杂交组合的3个幼胚组培苗株系,而播种的萌芽率为零.应用简单重复区间序列(ISSR)分子标记技术对F1代组培苗进行了亲子鉴定,其中15个随机引物在第1株杂交后代(F1-1)中共扩增出283条ISSR谱带,包括能在双亲中检出的275条和F1-1自身的特异带8条.在第2株杂交后代(F1-2)中有282条谱带能在双亲中检出,在第3株杂交后代(F1-3)中有288条谱带能在双亲中检出.卡平方检验表明,在F1-1、F1-2及F1-3中扩增出的谱带数与亲本中各对应位点所显示的谱带数之间没有显著差异.ISSR鉴定结果证实了杂种的真实性.     

美味猕猴桃海沃德与毛花猕猴桃种间杂交及优株的选育

对美味猕猴桃海沃德(2n=6x=174)和毛花猕猴桃(2n=2x=58)进行种间杂交的试验结果表明,两种间杂交有一定程度的亲和性,杂种F1实生苗的形态特征,除个别性状倾向双亲一方外,其余均介于双亲之间,其中花瓣颜色尤为明显:全部杂种雌株的花为白色,与母本的相同,雄株有白色、桃红色和桃、白两色相间的3种类型。从杂种胚培养的实生苗中选出一株优良雌株,染色体数接近4倍体;过氧化物同工酶谱介于双亲之间。并就杂交双亲的倍性和其杂交亲和程度进行了讨论。     

柑橘种间体细胞杂种植株遗传变异研究

对6年生哈姆体甜橙 粗柠檬和4年生伏令夏橙 宜昌橙种间体细胞杂种遗传变异进行了研究。体细胞杂种气孔较大,密度较小,染色体数为四倍体（2n=4x=36)。POX、PPO、GOT和SOD4种同工酶图谱上,体细胞杂种为双亲酶带之和,RAPD分析显示,体细胞杂种含有双亲的谱带,同一融合组合不同单株在叶形指数、气孔特征、染色体数目,同工酶和RAPD图谱上表现一致。     

‘红江橙’天然多倍体的45S rDNA荧光原位杂交分析

 以实生筛选获得的红江橙三倍体和四倍体植株及其二倍体对照为试验材料,利用荧光原位杂交（Fluorescence In situ hybridization,FISH）技术分析了不同倍性红江橙体细胞染色体上45S rDNA的分布。结果表明,红江橙二倍体体细胞中期染色体中存在3个45S rDNA杂交位点,分别位于第1对染色体的核仁组成区和第8号染色体的整个随体上;三倍体体细胞中期染色体中存在4个杂交位点,其中有三个与二倍体基本相同,另外的一个位于第3号染色体的核仁组成区;四倍体体细胞中期染色体中存在6个杂交位点,分布的位置及区域和信号的强弱均与二倍体基本相同。供试材料体细胞间期核与中期染色体中的杂交信号数及强弱程度基本相似。通过分析,提出红江橙三倍体的形成与2n雌配子的形成有关,伴随有外源基因组的重组;四倍体可能产生于珠心系细胞的直接加倍,并且伴随有染色体的断裂和易位。     

柑桔体细胞杂种的花粉育性及其遗传稳定性

对原生质体融合产生的５个已开花的体细胞杂种的花粉育性观察表明，它们的花粉染色活力在０－９０．１８％之间。其中４个体细胞杂种的花粉育性介于双亲之间，偏向高值亲本；种间异源四倍体体细胞杂种产生７．１８％－１８．５９％的小花粉，这类花粉只有正常花粉粒的１／３左右大小、内空。脐橙与红桔的体细胞杂种不产生花粉。墨西哥来檬与伏令夏橙的体细胞杂种花粉育性稳定，年份间无显著差异；粗柠檬与哈姆林甜橙的体细胞杂种无性繁殖后代之间，花粉育性无显著差异。     

澳洲指橘与粗柠檬体细胞杂种倍性FCM分析及其花粉活力检测

利用流式细胞仪对5株澳洲指橘(Microcitrus papuana Swingle,2n=2x=18)与粗柠檬(Citrus jambhiri Osbeck,2n=2x=18)属间体细胞杂种进行倍性分析,以已知倍性的二倍体粗柠檬植株的峰对应荧光值(FL)50作为对照,5棵再生植株的FL值分别为51、51、47、52、48,表明这些体细胞杂种植株均为二倍体。同时,实验结果还表明,HR(HighResolution)试剂盒中的核提取液HR-A和染色液HR-B的最佳处理时间分别是5min和2min。体细胞杂种于2002年3月首次开花,对其花粉活力进行分析,结果表明体细胞杂种的花粉活力为50％～90％。     

柑桔体细胞杂种扦插繁殖及其有关性状研究

对３个由原生质体融合产生的柑桔体细胞杂种繁殖特性的研究表明，金柑与甜橙属间体细胞杂种扦插生根成活率较低。甜橙＋宜昌橙以及甜橙＋粗柠檬种间体细胞杂种扦插萌发和生根能力与权及粗柠檬没有显著差异；插条发根平均为２．０条和１．８条，一年生植株根系总长分别为１２２．２ｃｍ和８０．７ｃｍ，与积和粗柠檬均无显著差异；粗柠檬＋甜橙杂种的须根数为３９条，株－１，与权（５４．５条·株－１）差异显著，而宜昌橙＋甜橙种间杂种（４７．７条·株－１）与积差异不显著；体细胞杂种的抗寒性有介于双亲之间的趋势     

RAPD分子标记在果蔬研究中的应用

随机扩增多态性DNA(Random AmplifiedPolymorphism DNA,RAPD),是Williams等于1990年发展起来的以PCR为基础的新型分子标记技术。基本原理是:利用一系列(通常数百个)不同碱基序列的随机引物(8～10bp)对基因组DNA进行PCR扩增,通过凝胶电泳分析扩增产物DNA片段的多态性。其中,每个扩增片段代表基因组上的一个位点,这些扩增片段多态性反映了基因组相应区域DNA多态性。RAPD所用一系列引物DNA序列各不相同,每一特定引物,在基因组DNA上都有其特定的结合位点;如果基因组在这些区域发生DNA片段插入、缺失或碱基突变,特定结合位点的…     

‘满天红’ב红香酥’杂种鉴定及遗传变异Genic-SSR分析

【目的】对授粉时未做去雄处理的‘满天红’ב红香酥’组合进行杂种鉴定和遗传变异分析,排除非双亲杂种单株,为利用该组合进行连锁分析奠定基础。【方法】用9对从转录组数据开发的在双亲间表现多态性的genic-SSR引物和1对自交不亲和基因检测引物对‘满天红’ב红香酥’组合所有单株进行杂种鉴定、标记偏分离分析和群体聚类分析。【结果】348个杂交单株中,有339株同时拥有母本和父本来源的特征片段,真正为‘满天红’和‘红香酥’的杂种,其余9株在部分位点未见父本条带,排除为双亲杂种的可能。卡方检验发现6个位点符合孟德尔分离定律,4个出现偏分离现象。双亲和339个真正杂种后代经遗传聚类分析分为3组:一组包含77个后代,与‘满天红’聚在一起;另一组包含183个后代,与‘红香酥’聚到一起。另有79个后代,单独聚在一起。【结论】利用Genic-SSR分析成功地对‘满天红’ב红香酥’组合梨杂种后代进行了鉴定,表明外来花粉污染是造成杂交群体中非双亲杂种污染的主要原因,产生自交后代污染的概率较低,聚类分析表明S-RNAse和部分SSR位点在该杂交群体中发生偏分离,半数以上的单株与父本‘红香酥’聚为一类。     

SSR标记鉴定甜瓜品种‘红月亮’种子纯度

为明确甜瓜品种‘红月亮’F1代的种子纯度,通过提取甜瓜‘红月亮’子叶DNA,利用SSR(Simple Sequence Repeats)分子标记对甜瓜品种红月亮F1代种子DNA进行了PCR扩增、检测与分析。结果表明,在20个SSR引物组合对亲本及F1代筛选中,共有6对引物组合具有多态性,多态率30%。选择CMBR026用于‘红月亮’F1代种子纯度鉴定,使用该标记共检测118株,其中2株为自交株,种子纯度为98.3%;试验用的‘红月亮’种子田间鉴定纯度为99.5%,鉴定结果一致。SSR分子标记方法更能准确鉴别出‘红月亮’中的不纯株,且大大缩短纯度鉴定周期。     

柑桔同源及异源四倍体花粉育性研究

对８个柑桔同源四倍体及通过原生质体融合得到的２个异源四倍体的花粉育性和花粉粒大小进行了测定。结果显示，同源四倍体柑桔花粉育性平均为３６％，约为二倍体（６２％）的６０％。‘伏今夏’甜橙由于是异质结合的染色体易位突变体，其同源四倍体花粉育性比二倍体（２３％）高出５０％。权（Ｐｏｎｃｉｒｕｓｔｒｉｆｏｌｉａｔａ）与甜橙（Ｃｉｔｒｕｓｓｉｎｅｎｓｉｓ）属间以及来檬（Ｃ．ａｕｒａｎｔｉｆｏｌｉａ）与甜橙种间四倍体体细胞杂种花粉育性介于其双亲之间，花粉育性分别为各自高值亲本的９９％和７５％。同源及异源四倍体花粉粒体积平均为二倍体的２倍或双亲之和。本结果说明，柑桔体细胞杂种可作为杂交亲本进一步被利用。     

Evaluation of ‘Hamlin’ sweet orange + ‘Montenegrina’ mandarin somatic hybrid for tolerance to Xanthomonas axonopodis pv. citri and Xylella fastidiosa

Asiatic citrus canker (ACC), caused by Xanthomonas axonopodis Starr & Garces pv. citri (Hasse) Vauterin et al., and citrus variegated chlorosis (CVC), caused by Xylella fastidiosa Wells et al., are considered the main diseases affecting sweet orange scion varieties in Brazil. Among commercial varieties, mandarins and tangerines are recognized as tolerant to these pathogens. We report herein the production of ‘Hamlin’ sweet orange (Citrus sinensis L. Osbeck) + ‘Montenegrina’ mandarin (Citrus deliciosa Ten.) allotetraploid somatic hybrid plants by protoplast fusion with improved disease tolerance that could be used as a donor of resistance genes in interploid hybridisation. Somatic hybridisation was confirmed by leaf morphology, flow cytometry and RAPD analyses. The somatic hybrid was propagated by grafting and cultivated in a screenhouse for tolerance assays. For X. axonopodis pv. citri assays, buds were collected from both ‘Hamlin’ sweet orange and the somatic hybrid and grafted onto ‘Cleopatra’ mandarin (Citrus reshni hort. ex Tanaka). As a negative control, buds from ‘Mexerica Tardia’ mandarin (C. deliciosa) were collected and grafted onto ‘Cleopatra’ mandarin. Two-month old plants with at least one young vegetative flush were individually spray-inoculated with a 10⁶ CFU mL⁻¹X. axonopodis pv. citri suspension and incubated in a growth chamber, at 27 °C, under 16-h photoperiod. The somatic hybrid showed a statistically significant reduction in susceptibility to ACC 30 days after inoculation. Compared to ‘Hamlin’ sweet orange, disease severity was reduced by 70%, with similar tolerance to that of the mandarin negative control. For X. fastidiosa assays, buds were collected from the somatic hybrid and its parental plants and grafted onto ‘Rangpur’ lime (Citrus limonia Osbeck). The developed plants were needle-inoculated with a X. fastidiosa suspension (8.7 × 10¹⁰ CFU mL⁻¹) into the new growth flush stem. Bacterial population was quantified both at 4 (at the inoculation point) and 8 months (50 cm above the inoculation point) after inoculation. The first evaluation detected X. fastidiosa in 63% of ‘Hamlin’ sweet orange and ‘Hamlin’ + ‘Montenegrina’ mandarin samples. In the second evaluation, X. fastidiosa was detected in 47.4% of ‘Hamlin’ sweet orange and 10.5% of ‘Hamlin’ + ‘Montenegrina’ somatic hybrid samples, suggesting that bacterial movement was restricted in the somatic hybrid. X. fastidiosa was not detected in both evaluations in samples collected from leaves of ‘Montenegrina’ mandarin. These results indicate that the ‘Hamlin’ sweet orange + ‘Montenegrina’ mandarin somatic hybrid has potential for improved disease tolerance that should enhance its value regarding future use in citrus breeding programs.     

蕉柑起源与分类地位的研究

从植物学形态特征、孢粉学、核型、过氧化物酶（ＰＯＸ）同工酶等方面综合比较分析了蕉柑与两个甜橙品种（雪柑、柳橙）、两个桔类品种（红桔、碰柑）的异同。结果表明，蕉柑的多数性状表现为橙、桔的中间状态，有些性状表现倾向甜橙或桔类。多项遗传指标分析说明，蕉柑系起源于甜检和桔类的杂种，并为蕉柑的分类地位提供了科学证据。     

沙田柚（2x）× 柑橘异源体细胞杂种NS（4x）的三倍体后代遗传分析

 用两对SSR 引物TAA1 和TAA3 对以二倍体沙田柚为母本,体细胞杂种NS（Nova 橘柚 + Succari 甜橙）为父本,通过有性杂交和胚挽救获得的79 株三倍体后代群体的带型和分离情况进行了分析。结果发现TAA1 引物和TAA3 引物在后代群体中分别扩增出5 种带型和4 种带型,子代带型分别符合4︰1︰1︰5︰1 和2︰2︰1︰1 的分离比例,与根据孟德尔遗传规律推导的双二倍体的分离比例相吻合,初步表明柑橘异源四倍体体细胞杂种减数分裂行为类似于双二倍体。     

Evaluation of citrus somatic hybrids for tolerance to Phytophthora nicotianae and citrus tristeza virus

Somatic hybridization is a biotechnology tool that can be used in citrus breeding programs to produce somatic hybrids with the complete genetic combination of both parents. The goal of this work was to test the reaction of citrus somatic hybrids that may be useful as rootstocks to trunk and root infections caused by Phytophthora nicotianae van Breda de Haan (P. parasitica Dastur) and to citrus tristeza virus (CTV). The somatic hybrids evaluated were ‘Caipira’ sweet orange (Citrus sinensis L. Osbeck) + ‘Rangpur’ lime (C. limonia Osbeck), ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin (C. reshni hort. ex Tanaka), ‘Caipira’ sweet orange + ‘Volkamer’ lemon (C. volkameriana V. Ten. & Pasq.), ‘Caipira’ sweet orange + rough lemon (C. jambhiri Lush.), ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange (C. aurantium L.), ‘Rangpur’ lime + ‘Sunki’ mandarin (C. sunki (Hayata) hort. ex Tanaka), ‘Ruby Blood’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, and ‘Valencia’ sweet orange + Fortunella obovata hort. ex Tanaka. For P. nicotianae trunk and root infection assays, plants of the somatic hybrids, obtained from 9-month semi-hardwood cuttings, were evaluated and compared with diploid citrus rootstock cultivars after mycelia inoculation in the trunk or spore infestation in the substrate, respectively. ‘Cleopatra’ mandarin + sour orange, ‘Rangpur’ lime + ‘Sunki’ mandarin, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon had less trunk rot occurrence, whereas the somatic hybrids ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange, ‘Caipira’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Rangpur’ lime were tolerant to root rot. For CTV assays, plants of the somatic hybrids along with tolerant and intolerant rootstocks were budded with a mild strain CTV-infected or healthy ‘Valencia’ sweet orange budwood. Differences in average scion shoot length indicated that the hybrids ‘Cleopatra’ mandarin + sour orange and ‘Valencia’ sweet orange + Fortunella obovata were intolerant to CTV.     

Embryogenesis in vitro of several Citrus species and cultivars

Summary

A number of experiments were performed to obtain somatic embryos and embryogenie cell lines from several species and cultivars of citrus by in vitro ovule culture. The source of ovules (pre-anthesis and post-anthesis), incubation conditions (light and darkness) and several modifications of the culture medium were evaluated. All the species and cultivars assayed produced somatic embryos and “pseudobulbi”, but production of friable embryogenie callus was species dependent. The small proliferation of callus and globular bodies recovered from the primary cultures were suitable for recovering embryogenie callus lines by periodical subculturing into fresh medium. After several monthly subcultures discarding embryos and “pseudobulbi”, cell lines virtually devoid of organized structures were obtained from three cultivars of sweet orange, sour orange and Cleopatra mandarin. In all these species, embryogenesis was restored spontaneously and/or by substitution of sucrose by maltose or lactose in the culture medium. The embryos germinated and produced phenotypically normal plants.     

Somaclonal variation with early juice-sac granulation obtained by inter-specific protoplast fusion in citrus

Summary

Six plants with an early juice–sac granulation trait derived from inter-specific protoplast fusions between embryogenic calli of ‘Bonanza’ navel orange (Citrus sinensis [L.] Osbeck) and mesophyll protoplasts of ‘Dahongpao Red’ tangerine (C. reticulata Blanco) were analysed by flow cytometry and by using molecular markers, including simple sequence repeats (SSR) and restriction fragment length polymorphism (RFLP). The results indicated that all six plants were diploids and had inherited their nuclear DNA from the embryogenic callus parent ‘Bonanza’ navel orange. However, an analysis of morphological and fruit characteristics, and measurements of components of the cell walls in the juice-sacs, showed that they were not true-to-type for ‘Bonanza’ navel orange, especially for fruit traits such as juice-sac granulation and navel structure. These results confirmed that these plants were not hybrids, and were more likely to be somaclonal variants that arose during the regeneration of the navel orange protoplasts. These plants will provide material for studying the mechanism of granulation in juice-sacs, a common phenomenon during the storage of pummelo and other citrus fruits.     

两种柑橘线粒体DNA的获得与AFLP分析

为了研究柑橘种属间线粒体基因组的遗传多样性以及温州蜜柑胞质雄性不育的分子基础，采用了两个柑橘品种‘国庆1号’温州蜜柑和无核‘冰糖橙’的胚性愈伤组织作为提取线粒体的材料。不连续蔗糖梯度超速离心法纯化线粒体。提取的线粒体完整，具很强的荧光活性。mtDNA片段在20kb左右，且无降解。叶绿体探针rubisco L、核探针45 s rRNA Southem blotting没有检测到叶绿体DNA与核DNA，而线粒体探针apt6杂交获得一条5kb大小的带，说明用此提取方法可获得无污染的mtDNA。4对AFLP引物共得到98条带，其中14条带有多态性。