利用等位酶对油松无性系种子进行父本分析

利用水平淀粉凝胶电泳8种酶10个位点34个等位基因,对辽宁兴城油松无性系种子园中17个无性系20个单株的200粒种子作了父本分析。无性系雄花量的多少与授粉果率并不成正比;不同无性系对花粉的接受存在一定的选择性,分析试样单株与周围的无性系并没有构成固定的授粉组合,说明授粉期风向等气象因子,无性系的雌雄花器的构造,受精等对受粉的成败都有作用,种子园结实初期自交现象并不明显,在分析试样中只有16＃,17＃,19＃无性系存在自交现象;种子园内花偻的有效传播一般在半径30m范围内,同时,分析了种子园子代的等位酶变异和空间遗传结构,从另一侧面反映出采种母树周围花粉分布比较均匀,并说明散粉期间风向等气象因子对授粉成败影响较大。     

空间条件对几种粮食作物的同工酶和细胞学特性的影响

搭载１９８７年发射的两颗返地卫星（８月５—１０日和９月９—１７日）的几种小麦、大麦种子,经回收后初步研究表明：（１）对发芽率的影响：空间处理的种子,其发芽率与对照无差别;（２）对茎及生育期的影响：空间处理的种子长成的幼苗比对照强壮,植株高度有些品种明显的矮于对照。生育期有不同程度延长;（３）对染色体结构的影响：花粉母细胞减数分裂观察表明搭载卫星的种子当代可诱导出比地面更多的染色体桥、落后染色体及染色体数目异于正常体细胞数目的现象。小麦品种Ｃｏｃｏｒｉｔ—７１经空间处理后花粉母细胞的染色体数目异常可高达２０．５１％,而地面对照组其花粉母细胞基本正常（２ｎ＝２８）;（４）对同工酶的影响：经空间处理的小麦种子酯酶、过氧化物酶的同工酶谱带空间处理的比地面对照减少。由此可见,空间处理可诱导纯合植物种子发生变异,为农作物育种创造一个新途径。     

森林低温霜冻灾害干扰研究综述

在全球变暖的背景下,森林低温霜冻灾害的发生并没有减少趋势,低温霜冻灾害的发生可能对林木的组织或整个幼树、幼苗产生致命伤害,进而成为林木生长发育,天然或人工更新的一个主要限制因子。森林低温霜冻灾害的发生和危害程度取决于林木生长复杂多变的物理环境和树木的耐冻性,前者又受大尺度环流形势及局地尺度小气候特征的影响。借助于3S技术建立复杂地形下低温和光照的空间分布模型,并结合林木的耐冻性,构建低温霜冻危害评估的概率模型,将有助于提高霜冻灾害的监测和危害评估水平。森林低温霜冻的防御应考虑将物理与生物防霜方法相结合,前者通过建防护林和采取合适的采伐措施,来改善林内地表的辐射平衡;后者则通过生物技术手段来增强林木的耐冻性。需结合霜冻灾害的监测和危害评估模型,对各种不同防霜措施的防霜效果进行定量评估。     

植物交配系统的进化、资源分配对策与遗传多样性

影响植物自交率进化的选择力量主要体现在两个方面：当外来花粉量不足时,自交可以提高植物的结实率,即雌性适合度（繁殖保障）;而如果进行自交的花粉比异交花粉更易获得使胚珠受精的机会,那么自交也可以提高植物的雄性适合度（自动选择优势）。但是,鉴别什么时候是繁殖保障、什么时候是自动选择优势导致了自交的进化却是极其困难的。花粉贴现降低了自交植物通过异交花粉途径获得的适合度,即减弱了自动选择优势,而近交衰退既减少了自动选择优势也减少了繁殖保障给自交者带来的利益。具有不同交配系统的植物种群将具有不同的资源分配对策。理论研究已经说明,自交率增加将减少植物对雄性功能的资源分配比例,但将使繁殖分配加大,而且在一定条件下交配系统的改变甚至可以导致植物生活史发生剧烈变化,即从多年生变为一年生。文献中支持自交减少植物雄性投入的证据有很多,但是对繁殖分配与自交率的关系目前还没有系统的研究。资源分配理论可以解释植物繁育系统的多样性,尤其是能够说明为什么大多数植物都是雌雄同体的。自交对植物种群遗传结构的影响是减少种群内的遗传变异,增加种群间的遗传分化。长期以来人们一直猜测,自交者可能会丢掉一些长期进化的潜能,目前这个假说得到了一些支持。     

植物交酸系统的进化、资源分配对策与遗传多样性

影响植物自交率进化的选择力量主要体现在两个方面：当外来花粉量不足时,自交可以提高植物的结实率,即雌性适合度（繁殖保障）;而如果进行自交的花粉比异交花粉更易获得使胚珠受精的机会,那么自交也可以提高植物的雄性适合度（自动选择优势）。但是,鉴别什么时候是繁殖保障、什么时候是自动选择优势导致了自交的进化却是极其困难的。花粉贴现降低了自交植物通过异交花粉途径获得的适合度,即减弱了自动选择优势,而近交衰退既减少了自动选择优势也减少了繁残给自交者带来的利益。具有不同交配系统的植物种群将具有不同的资源分配对策。理论研究已经说明,自交率增加将减少植物对雄性功能的资源分配比例,但将使繁殖分配加大,而且在一定条件下交配系统在改变甚至可以导致植物生活史发生剧烈变化,即从多年生变为一年生。文献中支持自交减少植物雄性投入的证据有很多,但是对繁殖分配与自交率的关系目前还没有系统的研究,资源分配理论可以解释植物繁育系统的多样性,尤其是能够3说明为什么大多数植物都是雌雄同体的,自交对植物种群遗传结构的影响是减少种群内的遗传变异,增加种群间的遗传分化,长期以来人们一直猜测,自交者可能会丢掉一些长期进化的潜能,目前这个假说得到了一些支持。     

杉木种子园种子产量及其主导影响因子的分析

 为研究我国杉木种子园产量的主导影响因子及影响效应,调查收集了安徽西田、福建洋口和官庄、广东小坑4个林场杉木（Cunninghamia lanceolata）种子园历年种子产量及与种子生产年份对应的有关气象资料,以开花受粉、幼果发育各个不同时期的20个气象因子与种子产量进行逐步回归分析,探讨我国杉木种子园产量的大小年现象及周期特征。研究结果表明,杉木种子园投产初期大小年现象不显著,投产中、后期大小年现象出现的年度及周期特征完全一致,种子大小年周期一般为2～3年。在同一地区气候条件相似的情况下,即使立地条件、     

二维码在林木种子园信息化管理中的应用

利用二维码制作简单、成本低廉、信息存储容量大、容错性强、安全性高、识别速度快等优点,本研究将其应用于林木种子园各功能区信息化管理建设中。根据种子园各功能区的特点,在不同的功能区采用二维码记录不同的信息,更利于管理和区分,进而提升种子园科技管理含量,提高种子园管理效率,使种子园管理更加规范、迅捷、系统和全面。并且利用二维码技术,更有利于种源追溯和管理,进而提升良种的价值。本研究有助于今后林木种子园长远的发展和未来信息化管理的建设,同时也将为林木领域信息化管理提供新思路。     

凉水自然保护区阔叶红松林林分空间结构特征及其与影响因子关系简

根据凉水自然保护区28块典型阔叶红松林样地的5个林分空间结构参数和18个影响因子数据,采用典范对应分析（CCA）方法,对凉水自然保护区阔叶红松林林分空间结构与影响因子间关系进行分析。研究结果表明：（1）研究区域阔叶红松林整体具有较好的林分空间结构,其水平分布格局主要表现为随机分布,树木生长整体处于中庸状态,林木的整体混交程度较高;（2）林分空间结构的CCA排序较好的揭示了该区林分空间结构与影响因子的关系;CCA第一排序轴反映了林龄、坡度、阔叶比和坡向的变化,第二排序轴反映了坡向、土壤有机质和平均胸径的变化,上述6因子的组合是决定林分空间结构特征的主要影响因子;（3）影响林分空间结构的变量中,地形、土壤和林分因子共解释了林分空间结构变化的59.20%,其中纯地形因子占30.68%,纯林分因子占19.01%,纯土壤因子占8.21%,未能解释部分为40.80%。     

不同脱水处理对桔梗花粉离体萌发及贮藏性能的影响

对桔梗花粉离体萌发条件进行了筛选,并采用花粉离体萌发法测定了不同干燥方式和贮藏时间处理对桔梗花粉生活力的影响;同时采用人工授粉的方法研究了不同处理后桔梗花粉授粉结实能力的变化。结果表明：（1）30℃培养1.5h是桔梗花粉离体萌发和花粉管生长的最佳培养条件。（2）不同干燥方式、不同干燥时间处理后桔梗花粉萌发率和花粉管长度均有所下降,但下降幅度不同,其中以干燥箱45℃烘干处理1.5h~2h下降最少,其花粉耐藏性也有明显提高。（3）不同干燥方式处理桔梗花粉后其授粉结籽率的变化明显不同,阴置2h处理的花粉结籽率最低,而干燥器内放置6h、日晒2h和烘干1.5h处理后花粉结籽率略有变化;干燥处理后随贮藏时间的增加,其授粉结籽率均呈下降趋势,但45℃烘干1.5h处理的花粉结籽率下降速度最慢,其授粉结籽能力可保持5d左右。     

樟子松无性系生长性状与结实量变异研究

为选育高产、优质的樟子松种质资源,本研究以吉林省白城市林木种子园的304个樟子松无性系为材料,对其生长性状（树高、地径、胸径、3 m处直径、冠幅、分枝角度和侧枝粗度）和结实性状（2015、2016和2017年的结实量）进行调查分析。方差分析结果表明除冠幅外无性系间各性状差异均达极显著水平（P<0.01）;各指标表型变异系数的变化范围为3.79%~65.22%,重复力变化范围为0.24~0.70;相关性分析结果表明除侧枝粗度与3 m处直径相关未达到显著水平外,树高、胸径、地径、冠幅与侧枝粗度间相关均达极显著水平,不同树龄的结实量与大部分生长性状相关未达显著水平。依据生长性状,以5%的入选率对无性系进行综合评价,15个无性系入选,入选无性系在树高、地径、胸径、3 m处直径、分枝角度和侧枝粗度等指标的遗传增益分别为5.47%、4.48%、15.18%、11.78%、2.38%和6.66%;依据3年结实量,以5%的入选率对无性系进行综合评价,15个无性系入选,入选无性系在2015年、2016年和2017年的平均结实量的遗传增益分别为2.89%、46.32%和13.88%。该研究为樟子松种子园优良无性系的选择提供材料,也为吉林西部樟子松良种选育提供基础。     

Gene flow and mating system in five <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> D. Don seed orchards as revealed by analysis of microsatellite markers

We investigated gene flow in five Cryptomeria japonica D. Don seed orchards of two different types (common and miniature) at widely spaced locations using microsatellite markers. The quality of a seed crop is determined by many factors, including pollen contamination from outside sources, self-fertilization, and the proportion of contributions from constituent clones. Contamination rates were found to vary among ramets both within seed orchards (10.0–76.7% in the most variable seed orchard) and among seed orchards (35.0–65.8% on average). Among ramets, there were significant negative correlations between pollen contamination rate and their distance from the orchard edge; among seed orchards, there were significant positive correlations between the pollen contamination rate and the C. japonica forest area nearby. Some proportion of the pollen (10.7% of total contamination) also migrated from parts of the orchards that had not been treated with gibberellin to induce flowering. Self-fertilization rates varied among seed orchards (1.4–4.4% on average), and there were significant positive correlations between self-fertilization rate and the number of ramets per clone in both types of seed orchard. Contributions as pollen donors differed significantly among clones in all seed orchards. The distance between planted ramets, flowering phenology, and relative pollen fecundity may also have contributed to observed differences in paternal contribution. The influence of these factors on genetic potential did not differ greatly between the two types of orchards. This work was supported by grants from the Pioneer Special Studies Program of the Japanese Ministry of Agriculture, Fishery, and Forestry; the Program for Promotion of Basic Research Activities for Innovative Biosciences; and research fellowships from the Japan Society for the Promotion of Science for Young Scientists.     

Prediction of genetic gain and gene diversity in seed orchard crops under alternative management strategies

Genetic gain and the gene diversity of seed crops from clonal seed orchards were formulated considering genetic selection, fertility variation and pollen contamination, and compared for five different management strategies. Genetic response was studied as a function of orchard management tactics. Management variables included the proportion of clones left after genetic thinning and/or selective seed harvesting. Formulae were derived to calculate gene diversity (expressed as group coancestry or status number) based on the sex ratio in an orchard population. The influence of having different sets of clones serving as seed parents, or pollen parents, or as both, was analysed. In addition, the impact on genetic gain and the gene diversity of seed crops was studied quantitatively as a function of the quantity and quality of gene flow from outside the orchard. The negative impact of fertility variation among orchard genotypes on the gene diversity of the seed crop was quantified. Numerical examples were given to illustrate the impact of orchard management alternatives on genetic gain and gene diversity. The formulae and results of this study can be used for identifying favourable alternatives for the management of seed orchards. Received: 16 December 2000 / Accepted: 13 March 2001     

Mating dynamics of Scots pine in isolation tents

Seed orchards are forest tree production populations for supplying the forest industry with consistent and abundant seed crops of superior genetic quality. However, genetic quality can be severely affected by non-random mating among parents and the occurrence of background pollination. This study analyzed mating structure and background pollination in six large isolation tents established in a clonal Scots pine seed orchard in northern Sweden. The isolation tents were intended to form a physical barrier against background pollen and induce earlier flowering relative to the surrounding trees. We scored flowering phenology inside and outside the tents and tracked airborne pollen density inside and outside the seed orchard in three consecutive pollination seasons. We genotyped 5683 offspring collected from the tents and open controls using nine microsatellite loci, and assigned paternity using simple exclusion method. We found that tent trees shed pollen and exhibited maximum female receptivity approximately 1 week earlier than trees in open control. The majority of matings in tents (78.3 %) occurred at distances within two trees apart (about 5 m). Self-fertilization was relatively high (average 21.8 %) in tents without supplemental pollination (SP), but it was substantially reduced in tents with SP (average 7.7 %). Pollen contamination was low in open controls (4.8–7.1 %), and all tents remained entirely free of foreign pollen. Our study demonstrates that tent isolation is effective in blocking pollen immigration and in manipulating flowering phenology. When complimented with supplemental pollination, it could become a useful seed orchard management practice to optimize the gain and diversity of seed orchard crops.     

Effects of male fecundity, interindividual distance and anisotropic pollen dispersal on mating success in a Scots pine (Pinus sylvestris) seed orchard

Quantifying the effect of pollen dispersal and flowering traits on mating success is essential for understanding evolutionary responses to changing environments and establishing strategies for forest tree breeding. This study examined, quantitatively, the effects of male fecundity, interindividual distance and anisotropic pollen dispersal on the mating success of Scots pine (Pinus sylvestris), utilizing a well-mapped Scots pine seed orchard. Paternity analysis of 1021 seeds sampled from 87 trees representing 28 clones showed that 53% of the seeds had at least one potential pollen parent within the orchard. Pronounced variation in paternal contribution was observed among clones. Variations in pollen production explained up to 78% of the variation in mating success, which was 11.2 times greater for clones producing the largest amount of pollen than for clones producing the least pollen. Mating success also varied with intertree distance and direction, which explained up to 28% of the variance. Fertilization between neighboring trees 2.3 m apart was 2.4 times more frequent than between trees 4.6 m apart, and up to 12.4 times higher for trees downwind of the presumed prevailing wind direction than for upwind trees. The effective number of pollen donors recorded in the seed orchard (12.2) was smaller than the theoretical expectation (19.7). Based on the empirical observations, a mating model that best describes the gene dispersal pattern in clonal seed orchards was constructed.     

Stability in and correlation between factors influencing genetic quality of seed lots in seed orchard of Pinus tabuliformis Carr. over a 12-year span

Coniferous seed orchards require a long period from initial seed harvest to stable seed production. Differential reproductive success and asynchrony are among the main factors for orchard crops year-to-year variation in terms of parental gametic contribution and ultimately the genetic gain. It is fundamental in both making predictions about the genetic composition of the seed crop and decisions about orchard roguing and improved seed orchard establishment. In this paper, a primary Chinese pine seed orchard with 49 clones is investigated for stability, variation and correlation analysis of factors which influence genetic quality of the seed lots from initial seed harvest to the stable seed production over a 12 years span. Results indicated that the reproductive synchrony index of pollen shedding has shown to be higher than that of the strobili receptivity, and both can be drastically influenced by the ambient climate factors. Reproductive synchrony index of the clones has certain relative stability and it could be used as an indication of the seed orchard status during maturity stage; clones in the studied orchard have shown extreme differences in terms of the gametic and genetic contribution to the seed crop at the orchard's early production phase specifically when they severe as either female or male parents. Those differences are closely related to clonal sex tendency at the time of orchard's initial reproduction. Clonal gamete contribution as male and female parent often has a negative correlation. Clone utilization as pollen, seed or both pollen and seed donors should consider the role it would play in the seed crop; due to numerous factors influencing on the mating system in seed orchards, clonal genetic contribution as male parent is uncertain, and it has major influence on the genetic composition in the seed orchard during the initial reproductive and seed production phase.     

Pollen limitation and seed set associated with year-to-year variation in flowering of Gmelina arborea in a natural tropical forest

The year-to-year variations in flowering, pollen and fruit production in ten Gmelina arborea individuals in a natural forest were observed over a period of five years, 2009?2013, and pollinator visits were observed closely over two years, 2011 and 2012. A pollen supplementation experiment was also undertaken in two years (2011 and 2012) of contrasting flowering levels. Considerable year-to-year variations were observed in flower, pollen and fruit production. The observed variation represented a normal sequence of good-year and poor-year cycling which is most parsimoniously attributed to resource allocation. The average level of pollen production per individual tree in good flowering years oscillated between 6.6 and 9.62 × 10⁸, which in the poor flowering years was between 1.92 and 3.07 × 10⁸. The magnitude of pollen limitation across years was highly significant (p < 0.0001). Fruit set through supplemental pollination was 73% and 96% greater than that of the open-pollinated branches in the year 2011 and 2012, respectively. Pollen limitation, irrespective of the arrival of outcross pollen, can reduce annual seed set in predominantly bee-pollinated trees. However, various other factors may cause flower abortion in addition to pollen limitation. The results of this study would be very valuable to the seed orchard managers and the silviculturists to manage the seed production areas (SPAs) of G. arborea. The study ultimately recommends supplemental pollination in seed orchards of G. arborea for better genetic gain and good seed yield.     

Simultaneous estimation of pollen contamination and pollen fertilities of individual trees in conifer seed orchards using multilocus genetic data

Seed orchards of forest trees are established to produce genetically-improved seed for reforestation. Genetic efficiency requires seed orchards to be (1) reproductively isolated form surrounding trees, (2) that there be similar fertilities among all orchard trees, and (3) minimum inbreeding. Each aspect of seed orchard reproduction can be simultaneously estimated using the observed frequency of each multilocus gametic type contributed through fertilizing pollen and the expected multilocus gametic segregation frequencies of orchard tree and of the contaminating population. These genetic estimates are directly relevant to the genetics of the tree breeding program. The flexibility of sampling seed — the basic data for these techniques — allows great scope for hypothesis testing, including tests of the accuracy of predictions of biophysical models of pollen movement. A simple example and a white spruce seed orchard case study are presented to illustrate the estimation technique and to investigate its sensitivity.     

Leaf-rust resistance in rye (<Emphasis Type="Italic">Secale cereale</Emphasis> L.). 2. Genetic analysis and mapping of resistance genes <Emphasis Type="Italic">Pr3</Emphasis>, <Emphasis Type="Italic">Pr4</Emphasis>, and <Emphasis Type="Italic">Pr5</Emphasis>

The conventional way to drive modifications in old forest tree seed orchards is to establish progeny trials involving each parent tree and then evaluate its contribution to the performance of the progeny by estimating its general and specific combining ability (GCA and SCA). In this work, we successfully applied an alternative parent selection tactic based on paternity testing of superior offspring derived from a hybrid seed orchard established with a single Eucalyptus grandis seed parents and six E. urophylla pollen parents. A battery of 14 microsatellite markers was used to carry out parentage tests of 256 progeny individuals including two independent samples of selected trees and one control unselected sample, all derived from 6-year-old forest stands in eastern Brazil. Paternity determination was carried out for all progeny individuals by a sequential paternity exclusion procedure. Exclusion was declared only when the obligatory paternal allele in the progeny tree was not present in the alleged parent tree for at least four independent markers to avoid false exclusions due to mutation or null alleles. After maternity checks to identify seed mixtures and selfed individuals, the paternity tests revealed that approximately 29% of the offspring was sired by pollen parents outside the orchard. No selfed progeny were found in the selected samples. Three pollen parents were found to have sired essentially all of the offspring in the samples of selected and non-selected progeny individuals. One of these three parents sired significantly more selected progeny than unselected ones (P0.0002 in a Fisher exact test). Based on these results, low-reproductive-successful parents were culled from the orchard, and management procedures were adopted to minimize external pollen contamination. A significant difference (P<0.01) in mean annual increment was observed between forest stands produced with seed from the orchard before and after selection of parents and revitalization of the orchard. An average realized gain of 24.3% in volume growth was obtained from the selection of parents as measured in forest stands at age 2–4 years. The marker-assisted tree-breeding tactic presented herein efficiently identified top parents in a seed orchard and resulted in an improved seed variety. It should be applicable for rapidly improving the output quality of seed orchards, especially when an emergency demand for improved seed is faced by the breeder.Communicated by D.B. Neale     

用RAPD标记检测鹅掌楸属种间杂交的花粉污染

根据鹅掌楸属 (LiriodendronL .)的生物学特点 ,实践上常采用不套袋杂交授粉技术 ,理论分析和间接检测结果证明这种杂交授粉方式的花粉污染率低于 1% ,但到目前为止仍缺乏直接的检测证据。本试验首次采用RAPD标记对鹅掌楸属种间不套袋杂交授粉的花粉污染率进行了检测 ,结果证明 93个受检不套袋杂交授粉子代均来自目的父本 ,而非花粉污染所致。通过对所用 4个父本标记谱带在试验群体中出现频率的测定和分析 ,证明这种检测结果的可靠性大于 99% ,从而认为对鹅掌楸属进行不套袋杂交授粉是可行的。并就这一方法在植物学研究领域的应用潜力进行了讨论     

RAPD Detection of Pollen Contamination in Cross Breeding of Liriodendron (in English)

Based on the biology peculiarity of Liriodendron L., the non-bagged pollination technique was used widely in cross breeding of the genus. Theoretical analysis and indirect detection indicated that the pollen contamination rate of this pollination technique was no higher than 1%. But there is no evidence from direct detection by now. The pollen contamination rate produced in this pollination technique, for the first time, was detected by means of RAPD markers in this study. The results revealed that all the 93 progenies detected, derived from the non-bagged pollination technique, were progenies of the purpose male tree of the cross. No pollen contamination was found. Because the frequency of the 4 paternal marker fragments selected for the detection were relatively low in the population, the reliability of the pollen contamination rate detected was very high (>99%). Therefore, the non-bagged pollination technique is viable in Liriodendron . The authors also considered that RAPD markers had higher potential of use in other fields of botanic study such as pollen competition, pollen flow, pollen contamination of forest seed orchard, etc.