国外松种间杂交后代生长和形态性状变异及相关性分析

利用随机区组设计营建的试验林资料,对6种树龄5年的国外松杂种后代生长和形态性状变异及其相关进行了分析,结果显示:国外松种间杂交后代不同物种,同一物种的不同家系,同一家系内的不同单株均表现出丰富的多样性,单株材积和树干通直度的变异系数达30%~50%;而其它形态、生长性状变异系数为2%~30%。这些杂交种丰富的生长和形态变异为多目标选择奠定了基础。以湿地松(Pinus elliottii Engelman var.elliottii)为母本的杂交松针叶长度变短,同时湿地松×洪都拉斯加勒比松(P.caribaea Morelet var.hondurensis(Senecl.)Barrett et Golfari)还表现出良好的干形性状(通直度好,分枝角小等)。以火炬松(P.taeda L.)为母本的杂交松对针叶的改良效果不明显,但是火炬松×洪都拉斯加勒比松单株平均材积大、干形通直、分枝角小、侧枝细,说明这个杂交类型具有生长快、树形紧凑等优良特性。相关分析显示生长快、针叶短、分枝角度小、树干通直度好这几个性状可以同步改良。研究认为国外松种间杂交后代生长性状不低于母本,在形态性状上湿地松×洪都拉斯加勒比松与母本相比针叶较稀疏,针叶长度较短,分枝角较小,因此比母本更能抵抗雨雪冰冻等自然灾害,这对于我国南方湿地松抗逆性育种具有重要的意义。     

萧氏松茎象危害与松树松脂量关系研究初报

萧氏松茎象HylobitelusxiaoiZhang是近年来暴发性松树害虫 ,主要危害 3种松树 :湿地松 (PinuselliottiiEngelm)、火炬松 (P .taeda)、马尾松 (P .massoniaanaLamb) ,其中以湿地松受害最为严重。为明确萧氏松茎象的危害与松脂流量的关系 ,作者对萧氏松茎象危害前后 3种松树 (湿地松、马尾松、火炬松 )松脂流量变化进行了研究。结果显示 ,在松树受害植株和未受害植株间松脂总流量间存在一定差异 ,其中以马尾松松脂流量变化最大 ,对受害株和未受害株松脂流量t-测验 ,差异达到显著水平 ;而湿地松和火炬松松脂总流量在受害植株和未受害植株间没有显著差异。对上述 3种松树松脂流量随时序动态变化的分析显示 ,松脂流量在 1年中以 5月到 6月之间为松脂流量高峰期 ,此后逐渐下降 ,到 3月中旬以后松脂流量又开始上升。就松脂流量时序动态而言 ,萧氏松茎象为害对马尾松松脂流量影响最大 ,对其它2个松树影响不明显。另外 ,不同松树树种在松脂流量及其时序动态上也存在一定差异 ,其中以马尾松脂流量较高。     

湿地松×洪都拉斯加勒比松遗传多样性的ISSR分析（英文）

杂交育种是产生遗传变异、表型变异及选择新变异的重要方法。然而系统发育不清晰,选择较近的亲缘关系亲本用于杂交子代往往表现出较低的遗传多样性。为探究湿地松、洪都拉斯加勒比松种间杂交后代遗传多样性水平,对8个湿地松×洪都拉斯加勒比松家系进行ISSR分析。利用10条引物共产生60个表达清晰可用于分析的标记,其中48个标记表现为多态性,占总标记数的80%;湿加松各个家系多态位点百分率在5%～23.33%之间;各个家系基因多样性指数在0.015 2～0.087 2之间,Shannon指数的范围在0.021 6～0.129 4之间(家系水平为0.293 4)。8个家系间的基因分化系数Gst为0.743 5,即总的遗传变异中有74.35%的变异存在于家系间,家系内的遗传变异占总遗传变异的25.65%。采用UPGMA法对湿加松的8个家系进行了聚类分析,确定了各个家系之间的遗传亲缘关系。8个家系间的基因流N_m为0.172 5,表明基因流处于较低水平。     

国外松种间杂交后代生长和形态性状变异及相关性分析简

利用随机区组设计营建的试验林资料,对6种树龄5年的国外松杂种后代生长和形态性状变异及其相关进行了分析,结果显示：国外松种间杂交后代不同物种,同一物种的不同家系,同一家系内的不同单株均表现出丰富的多样性,单株材积和树干通直度的变异系数达30%~50%;而其它形态、生长性状变异系数为2%~30%。这些杂交种丰富的生长和形态变异为多目标选择奠定了基础。以湿地松（Pinus elliottii Engelman var. elliottii）为母本的杂交松针叶长度变短,同时湿地松×洪都拉斯加勒比松（P.caribaea Morelet var. hondurensis(Senecl.) Barrett et Golfari）还表现出良好的干形性状（通直度好,分枝角小等）。以火炬松（P.taeda L.）为母本的杂交松对针叶的改良效果不明显,但是火炬松×洪都拉斯加勒比松单株平均材积大、干形通直、分枝角小、侧枝细,说明这个杂交类型具有生长快、树形紧凑等优良特性。相关分析显示生长快、针叶短、分枝角度小、树干通直度好这几个性状可以同步改良。研究认为国外松种间杂交后代生长性状不低于母本,在形态性状上湿地松×洪都拉斯加勒比松与母本相比针叶较稀疏,针叶长度较短,分枝角较小,因此比母本更能抵抗雨雪冰冻等自然灾害,这对于我国南方湿地松抗逆性育种具有重要的意义。     

干旱胁迫下水曲柳×大叶白蜡F1的光合特性研究

以水曲柳与大叶白蜡杂交F1为试材并对部分花粉进行了高压静电场处理,探讨干旱胁迫对种间杂交F1生长量、光合特性和叶绿素含量等指标的影响。结果表明:(1)干旱胁迫处理的F1在净光合速率、气孔导度、蒸腾速率的降低幅度分别比母本(水曲柳自由授粉子代M7S和M8S)平均低5.1%、27.55%和12.05%,F1的叶绿素含量降低幅度比M7S和M8S降低幅度小并且复水后F1叶绿素回复能力也较强。(2)母本效应对F1表现出明显的影响。(3)高压静电场处理花粉提高了杂交子代对干旱胁迫的适应能力,有效抑制了受胁迫植株的净光合速率、气孔导度和蒸腾速率的降低,但静电场处理F1在解除胁迫后叶绿素含量及光合恢复能力方面存在差异。(4)杂交组合M8A4T和M7A2T的抗旱优势比较明显,杂交组合M8A2T对抗旱性比较敏感但也具有很强的恢复力。该研究初步明确了水曲柳×大叶白蜡杂交各组合F1对干旱胁迫的光合特性的生理响应,为干旱半干旱地区选育优良树种奠定了基础。     

湿地松×洪都拉斯加勒比松遗传多样性的ISSR分析

杂交育种是产生遗传变异、表型变异及选择新变异的重要方法。然而系统发育不清晰,选择较近的亲缘关系亲本用于杂交子代往往表现出较低的遗传多样性。为探究湿地松、洪都拉斯加勒比松种间杂交后代遗传多样性水平,对8个湿地松×洪都拉斯加勒比松家系进行ISSR分析。利用10条引物共产生60个表达清晰可用于分析的标记,其中48个标记表现为多态性,占总标记数的80%; 湿加松各个家系多态位点百分率在5%～23.33%之间; 各个家系基因多样性指数在 0.015 2～0.087 2之间,Shannon指数的范围在 0.021 6～0.129 4之间(家系水平为 0.293 4)。8个家系间的基因分化系数G_st为0.743 5,即总的遗传变异中有74.35%的变异存在于家系间,家系内的遗传变异占总遗传变异的25.65%。采用UPGMA法对湿加松的8个家系进行了聚类分析,确定了各个家系之间的遗传亲缘关系。8个家系间的基因流N_m为 0.172 5,表明基因流处于较低水平。     

草木灰对四种松属种子发芽和幼苗生长的影响

火干扰不仅影响森林生态系统的结构与功能,而且影响群落更新与演替。为了研究草木灰对4种松属种子萌芽和幼苗生长的影响,在湖南省株洲市黄丰桥林场采集马尾松、云南松、湿地松和火炬松种子,以马尾松次生林火烧迹地的草木灰为基质,设置对照和3个草木灰处理,进行播种试验及生长观测。结果表明:(1)草木灰处理下4个物种的种子发芽率比对照试验低,并呈现随草木灰含量的增加而降低的趋势,低草木灰含量处理马尾松种子发芽率不及对照一半,中、高草木灰含量处理发芽率更低;云南松、湿地松和火炬松种子发芽率规律类似于马尾松,而高草木灰含量处理发芽率为0。(2)培养皿播种平均发芽时间比花盆播种长,无论草木灰处理还是培养条件(培养皿或花盆),马尾松和云南松种子平均发芽时间比湿地松和火炬松短。(3)4个物种种子播种14周后,对照试验中马尾松和云南松幼苗死亡率最低,而火炬松和湿地松幼苗死亡率相对增加。(4)播种14周后不同试验处理4个物种幼苗生长差异不明显。火炬松、湿地松、云南松和马尾松幼苗的单株平均干重分别达0.038、0.031、0.027、0.024 g。各物种叶干重按降序排列依次是火炬松(0.026 g)湿地松(0.019 g)云南松(0.017 g)马尾松(0.016 g),根和茎的干重比重相当,约占对应物种幼苗叶干重的三分之一。研究表明以草木灰为培养基质,马尾松和云南松种子的发芽率较高,平均发芽时间较短,更适合作为火烧迹地植被恢复先锋树种,为火干扰后选择人工促进天然更新树种提供参考。     

棉花种间杂交技术创新及育种程序的建立

创立的棉属种间杂交新方案对克服杂交不孕及F1不育性取得重大进展;获得了栽培种间(4n与2n)70个组合及陆地棉与14个野生棉种间大批量的高代种质资源,并已育成8个新品种,4个来自陆地棉×中棉,另外4个来自陆地棉与4种野生棉的杂种,为我国首次育成,其中石远321(冀棉24)为近年来国家区试中增产幅度最大的新品种,3年累计推广933.3×10³ hm².建成了有效的种间杂交育种体系.     

合成甘蓝型油菜中双隐性雄性核不育材料的发现及遗传规律分析

从甘蓝型油菜与白菜型油菜的种间杂交获得的甘蓝型油菜(Brassica napus)中发现了雄性不育单株,兄妹交株系和不育株与甘蓝型油菜常规杂交F1和F2株系的育性分离分析表明,该不育材料属于双隐性雄性核不育类型.利用育性分离株系的可育株自交和可育株与不育株间兄妹交等方法筛选出7个纯合可育株系,等位测验表明这7个纯合可育株系(B1～B7)中存在两种基因型:Ms1Ms1ms2ms2和ms1ms1Ms2MS2.该材料对油菜核不育基因定位和杂种优势利用研究有重要意义.     

马尾松-木荷不同比例混交林种内和种间竞争强度

分析不同比例组成的马尾松(Pinus massoniana)-木荷(Schima superba)混交林树木间的竞争关系,可为营造种间关系协调的马尾松混交林提供参考依据.以马尾松-木荷混交林为研究对象,根据其混交比例分别类型Ⅰ(对照,10马)、类型Ⅱ(8马2木)、类型Ⅲ(7马3木)、类型Ⅳ(6马4木)4种类型设置标准地...     

Two new spontaneous hybrids of American hard pines from Pinus sect. Trifoliae (Pinaceae) found in the unique Russian Sochi Arboretum

In the 1990s, an extraordinarily abundant live collection of the genus Pinus, including 49 species, 4 subspecies, and 7 interspecific hybrids, found in the Sochi Arboretum in Russia on the northeast coast of the Black Sea, was taxonomically revised. Among these taxa, two previously unknown interspecific hybrids of American hard pine species from P. sect. Trifoliae had arisen spontaneously in culture. These are described here as the new hybrid species Pinus × transamericana (P. muricata × P. rigida) and Pinus × critchfieldii (P. patula × P. taeda). All known natural or artificial interspecific hybrids within P. sect. Trifoliae are listed, and hybridization between American hard pine species is discussed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Somatic embryogenesis of Pinus rigida?×?P. taeda and the relationship between the initiation of embryogenic tissue and zygotic embryo development

The pitch-loblolly pine hybrid (Pinus rigida × P. taeda) has useful characteristics of the parents, but its exploitation is hindered by restrictions of conventional breeding and propagation methods. This study was undertaken to establish an effective in vitro system for propagating pitch-loblolly hybrid pine through somatic embryogenesis and to unravel the relationship between the efficiency of embryogenic tissue initiation and zygotic embryo development. To initiate embryogenic tissue, megagametophytes of developing seeds were used as explants. Seeds were collected weekly, examined, and tested during June and July 2004. The medium and seed collection date were the most important factors for the successful somatic embryogenesis of P. rigida × P. taeda. Five embryogenic lines were obtained using a modified P. taeda basal medium, and the highest initiation rate was 0.55%, for seeds collected in 2 weeks, between July 3 and 16. Histological observation revealed that zygotic embryos of those seeds were mostly at the proembryonic stage or in transition to precotyledonary stages. For the successful maturation of somatic embryos, abscisic acid and gellan gum were needed in the medium. The results show that, although further tests and development are required, somatic embryogenesis could provide a viable option for propagating P. rigida × P. taeda hybrids.     

Genomic consequences of interspecific Pinus spp. hybridization

Strong karotypic orthoselection does not fully account for genome size variation in pines. Adult F1 interspecific pine hybrids are fertile and the genomic consequences of hybridization can be studied using haploid female megagametophytes. Greater variation in genome size was hypothesized to occur in hybrids compared to their parental species and the variation was thought to be positively related to the phylogenetic distance between the parental species. Nuclear 1C DNA content of megagametophytes from four sets of fertile Pinus spp. F1 hybrids and their parents was determined using a laser flow cytometer. Fertile F1 hybrids included two sets of hard pine hybrid Pinus elliottii Engelm. x P. caribaea var. hondurensis Morelet and two Asian x New World soft pine hybrids P. wallichiana A.B. Jacks. x P. strobus L. (hybrid is known as P. x schwerinii ) and P. lambertiana Dougl. x P. armandii Franchlet. Fertile, adult F1 produce haploid megagametophytes with nuclear DNA contents comparable to the parents or parental species. One genomic consequence of hybridization in pines is stability in nuclear DNA content. Hybrid genomes neither increased or decreased DNA content regardless of the phylogenetic distance between parents. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 503–508.     

Co-invading ectomycorrhizal fungal succession in pine-invaded mountain grasslands

Ectomycorrhizal (EM) fungal communities that associate with invading pines (Pinus spp.) are expected to be poor in species diversity. However, long-term successional trajectories and the persistence of dispersal limitations of EM fungi in the exotic range are not well understood. We sampled the roots and surrounding soil of Pinus elliottii and P. taeda trees invading mountain grasslands of Argentina. We also sampled the EM fungal spore bank in grassland soil near (∼150 m) and far (∼850 m) from the original pine plantations. We found 86 different co-invasive EM fungal OTUs. Differential dispersal capacities among EM fungi were detected in the spore bank of grassland soil, but not under mature pines. After thirty years of invasion, the age, but not the degree of spatial isolation of pine individuals affected the EM fungal composition. We showed how EM fungal succession occurs during pine invasions, which may have clear consequences for ecosystem functioning of co-invaded sites.     

Phenotypic analysis of first-year traits in a pseudo-backcross {(slash x loblolly) x slash} and the open-pollinated families of the pure-species progenitors

A single test, including one pseudo-backcross (Pinus elliottii x Pinus taeda) x P. elliottii and open-pollinated families of the pure species progenitors, was established in North Central Florida in December 2007 to study the transfer of the fast-growing characteristics from a P. taeda L. (loblolly pine) parent into the P. elliottii Engelm. (slash pine) background. Several traits were measured in the first growing season: height growth, phenology, tip moth incidence, stem traits, crown architectural and needle traits. Heterosis was evaluated for each trait using analyses of variance by fitting a linear mixed model. All traits were significantly (p value < 0.05) different among families while the significance for heterosis varied by trait. Positive heterosis was found for average rate of shoot elongation (ASRE), total growth (TG), total height and number of needles per fascicle while the opposite was true for base diameter, top diameter, fascicle length, fascicle diameter, crown projected area and phenological traits (cessation, duration and day to reach 50% of the height). Average performance (i.e., no heterosis) was found for initiation of growth, number of branches, number of nodes, tip moth incidence, sheath length and specific leaf area. The analyses indicated that introgression of loblolly pine alleles into slash pine was effective and novel trait combinations were achieved. The pseudo-backcross had larger variation in early height growth than the slash pine families and was taller than all open-pollinated families at the end of the first season. Tip moth incidence was much lower than the loblolly pine family.     

Transpecific microsatellites for hard pines

Microsatellites are difficult to recover from large plant genomes so cross-specific utilisation is an important source of markers. Fifty microsatellites were tested for cross-specific amplification and polymorphism to two New World hard pine species, slash pine (Pinus elliottii var. elliottii) and Caribbean pine (P. caribaea var. hondurensis). Twenty-nine (58%) markers amplified in both hard pine species, and 23 of these 29 were polymorphic. Soft pine (subgenus Strobus) microsatellite markers did amplify, but none were polymorphic. Pinus elliottii var. elliottii and P. caribaea var. hondurensis showed mutational changes in the flanking regions and the repeat motif that were informative for Pinus spp. phylogenetic relationships. Most allele length variation could be attributed to variability in repeat unit number. There was no evidence for ascertainment bias.     

Detection of hybridization between two loach species (<Emphasis Type="Italic">Paramisgurnus dabryanus</Emphasis> and <Emphasis Type="Italic">Misgurnus anguillicaudatus</Emphasis>) in wild populations

Artificial interspecific hybrids between large scale loach P. dabryanus and tetraploid pond loach M. anguillicaudatus (Cobitidae, Cypriniformes) are viable. To detect the occurrence of possible natural hybridization, genetic analyses by using microsatellite markers were performed for natural populations of large scale loach and pond loach, the reciprocal laboratory hybrids, and “supposed hybrids” with ambiguous morphology. The fertility of the artificial hybrids was also tested. At one diagnostic microsatellite (Mac50), one out of 20 “supposed hybrids” was identified to be F₁ hybrid between the two loach species because it had the same genotype as that of the laboratory hybrids. The triploid hybrids between the two species were confirmed to be female-sterile. The results show that rare hybridization has occurred between diploid large scale loach and tetraploid pond loach in nature although it may have little effect in genetic introgression. This study is helpful for fish conservation and encourages further investigation on natural hybridization and introgression of loaches.