苏太猪SLA-DQB和SLA-DRB基因第2外显子多态性及其与繁殖性能的关联分析

采用PCR-RFLP技术对苏太猪SLA-DQB及SLA-DRB基因第2外显子PCR产物进行分析。结果表明,苏太猪SLA-DQB基因经RsaⅠ酶切后共产生3种等位基因,5种基因型;SLA-DRB基因经RsaⅠ酶切后共产生3种等位基因,4种基因型。χ2适合性检验表明,苏太猪SLA-DQB及SLA-DRB基因外显子2的RsaⅠ酶切位点均达到了Hardy-Weinberg平衡状态。将SLA-DQB和SLA-DRB基因的基因型进行组合,共产生12种组合基因型,BBDF的第3胎繁殖性能总产仔数、产活仔数、初生窝重和断奶仔猪数显著高于组合基因型AADD、AADF、ABDD和CCDF(P<0.05)。从繁殖性能看,BBDF在群体中为最优秀的组合基因型。     

苏太猪SLA-DQB及DRB基因第2外显子多态性及其与繁殖性能的关联分析

采用PCR-RFLP技术对苏太猪SLA-DQB及DRB基因第2外显子PCR产物进行分析，结果表明：苏太猪SLA-DQB基因经RsaⅠ酶切后共产生3种等位基因，5种基因型；SLA-DRB基因经RsaⅠ酶切后共产生3种等位基因，4种基因型。χ2适合性检验表明，苏太猪SLA-DQB及DRB基因外显子2的RsaⅠ酶切位点均达到了Hardy-Weinberg平衡状态。将SLA-DQB和DRB基因的基因型进行组合，共产生12种组合基因型，BBDF的第3胎繁殖性能总产仔数、产活仔数、初生窝重和断奶仔猪数显著高于组合基因型AADD、AADF、ABDD和CCDF（P＜0.05）。就繁殖性能而言，BBDF在群体中为最优秀的组合基因型。     

崂山奶山羊骨桥蛋白基因(OPN)部分片段多态性及其与生产性状的关联分析

骨桥蛋白(osteopontin,OPN)是一种分泌型糖基化磷蛋白,在介导骨组织细胞与骨基质的连接过程中发挥重要作用.为了加快奶山羊的遗传进展,为奶山羊生产性状的标记辅助选择提供理论依据,本研究利用DNA混合池技术和高分辨率熔解曲线分析技术,检测了崂山奶山羊(Capra hircus)泌乳母羊的OPN基因多态性,并采用最小二乘方法分析其与泌乳和生长性状之间的关联效应.在所有174只样本中共检测到2个SNPs,即位于第5内含子I355位点的C/T(以C/r表示)和第7外显子E341位点的C/T(以M/N表示),其多态信息含量(PIC)分别为0.2773和0.3267,其等位基因和基因型频率在育种场(F)和育种户(P)群体中的分布不均衡,I355位点的P群体偏离Hardy-Weinberg平衡状态(P＜0.05),其他均处于平衡状态(P＞0.05).在与泌乳性状的关联分析中,P群体除电导性状以外的所有性状表型值均极显著(P＜0.01)高于F群体;I355位点上,CC基因型个体的脂肪含量显著(P＜0.05)高于CT和TT基因型个体,灰分和冰点性状显著(P＜0.05)高于CT基因型个体；E341位点上,等位基因N为非脂肪物、乳糖率、乳密度、乳蛋白率、冰点以及灰分6个性状的有利等位基因,所有性状差异均不显著(P＞0.05).在与生长性状的关联分析中,F群体的体重和体长均极显著(P＜0.01)高于P群体；P群体的尻宽和尻长极显著(P＜0.01)高于F群体;I355位点上,TT基因型个体的体重极显著(P＜0.01)大于CC基因型个体；E341位点上,等位基因M为体高和胸围的有利等位基因,MM和MN基因型个体的体重和尻宽极显著(P＜0.01)高于NN基因型个体,MM基因型个体的体长极显著(P＜0.01)高于NN基因型个体,MM基因型个体的体高、胸围显著(P＜0.05)高于NN基因型个体.本研究发现OPN基因突变位点I355与乳中脂肪和碳水化合物的含量相关,突变位点E341与奶山羊的生长发育性状有显著的关联效应,可以作为奶山羊部分生产性状的分子遗传标记.     

崂山奶山羊乙酰辅酶A羧化酶α基因(aCA CA)多态性及其与泌乳性状的相关分析

利用高效液相色谱法(denaturing high-performance liquid chromatography,DHPLC)和直接测序法,检测了174只崂山奶山羊(Capra hirc us)泌乳母羊的ACA CA基因启动子PⅢ位点多态性,采用最小二乘方法分析其与泌乳性状之间的关联效应.结果显示,在启动子PⅢ部分序列中共检测到3个SNPs,即第1206位的B/D,1255位的A/C和1322位的M/N,其等位基因和基因型频率在种羊场(F)和农户(P)两个群体中分布不均衡,均处于Hardy-Weinberg平衡状态(P＞0.05).在两个样本群中,大部分泌乳性状均存在显著的场别效应(P＜0.01或P＜0.05),而位点的基因型效应均不显著(P＞0.05).在F群体的1206位点上,等位基因B为乳蛋白率、乳糖率、非脂肪物性状的有利等位基因,BB基因型与BD基因型的乳蛋白率和乳糖率性状差异极显著(P＜0.01),非脂肪物和乳密度性状差异显著(P＜0.05),乳蛋白率、乳糖率和非脂肪物性状均存在显著的等位基因替代效应(P＜0.05);而在P群体中,两种基因型之间的所有性状则差异不显著(P＞0.05).在F群体的1322位点上,等位基因N为乳糖率的有利等位基因,为300 d产奶量的不利等位基因,MN基因型与MM基因型的300 d产奶量和乳糖率性状差异显著(P＜0.01或P＜0.05),其等位基因替代效应分别为-52.22 kg和0.12％(P＜0.01);而在P群体中,等位基因M为乳蛋白率、乳糖率、非脂肪物、乳密度的有利等位基因,基因型MM与MN在乳蛋白率、乳糖率、非脂肪物和乳密度性状均存在显著差异(P＜0.05),乳糖率和非脂肪物的等位基因替代效应分别为-0.25％和-0.44％(P＜0.05).研究结果提示,ACACA基因启动子PⅢ相同等位基因在不同育种群体中,对乳蛋白率、乳糖率、非脂肪物、乳密度、300 d产奶量存在不同程度的影响.     

新疆多浪羊FecB突变检测及与产羔数的关系

骨形态发生蛋白受体IB基因(BMPR-IB)FecB突变是影响布鲁拉美利奴和小尾寒羊高繁殖力的主效基因.本研究采集产双羔及以上的多浪羊(Ovis aries)母羊135只及后代羔羊血样共353份,公羊血样211份,利用PCR-RFLP技术检测FecB突变,并分析不同基因型个体母羊的产羔数.结果表明:在多浪羊群体中检测到BB、B+和++基因型,基因型频率分别为0.005,0.146和0.849.B+型多浪羊产羔数均值比++型多0.51只(P<0.01),BB型多浪羊产羔数分别与B+和++型差异不显著.多浪羊群体在FecB位点上处于Hard-Weinberg平衡状态,表明在该位点上没有受到选择的影响.本研究首次在新疆多浪羊群体中发现了FecB突变BB基因型公、母羊个体(1只公羊和2只母羊),揭示多浪羊多羔产生的机理可能与布鲁拉美利奴和小尾寒羊相同,在生产过程中可以根据携带FecB突变的情况开展选种选配,组建多浪羊肉用高繁品系.     

适宜多基因型青杨杂种叶片再生体系建立

以青杨杂种全同胞家系内30个基因型的叶片为外植体,研究培养基、基因型及基因型×培养基互作效应对青杨杂种叶片分化的影响,筛选适合多基因型青杨叶片分化的广谱型培养基,为对青杨从群体水平进行遗传转化和多倍体诱导奠定技术基础。研究结果表明:(1)基因型、培养基、基因型×培养基互作效应对青杨杂种叶片分化的影响极显著。(2)筛选出适合多基因型叶片分化的广谱型培养基为MS+6-BA0.4 mg·L-1+NAA 0.05 mg·L-1,可满足56.7%的青杨杂种基因型叶片分化,分化率可达70%以上。研究认为:在对群体再生生产中,应充分利用基因型×培养基互作效应,通过广谱型培养基实现大多数基因型青杨杂种叶片分化体系建立,并通过特殊培养基解决特殊基因型的青杨杂种叶片分化体系建立问题。     

抗粘液病毒基因（Mx）S631N多态位点与白耳鸡免疫性状和生产性能的关联分析

通过PCR-RFLP方法检测抗粘液病毒基因(Mx)S631N多态位点的等位基因A和G在白耳鸡群体中的分布;通过选配组建三种不同基因型群体(AA,AG,GG),免疫后分别于35日龄、42日龄、49日龄、70日龄和100日龄采用血凝和血凝抑制方法测定不同基因型个体的禽流感(AI)和新城疫(ND)抗体滴度,并测定不同基因型个体的90日龄体重、开产日龄和72周龄产蛋数;分析该多态位点与免疫性状和生长性状的关联.结果表明,在白耳鸡群体中Mx基因S631N多态位点的等位基因频率处于Hardy-Weinberg平衡状态(P>0.05),3种不同基因型频率分别为0.233(AA),0.517(AG)和0.250(GG);在测定的日龄内不同基因型个体的AI抗体滴度和ND抗体滴度水平呈现出类似的增长和消减变化,在多个测定日龄内从基因型个体的AI抗体滴度和ND抗体滴度水平显著高于AG和GG基因型个体(P<0.05);关联分析结果表明,该多态位点与49日龄时的ND抗体滴度峰值和70日龄时的AI抗体滴度峰值间均存在显著关联(P<0.05),但不同基因型个体间的90日龄平均体重、开产日龄和72周龄产蛋数差异均不显著(P>0.05).研究结果证实Mx基因S631N多态位点可以作为提高抗病力的重要候选标记位点.     

分子标记辅助选择选育高抗性淀粉水稻新品种

为建立高效高抗性淀粉(RS)水稻新品种培育的分子标记辅助选择育种体系,以降糖稻1号为高RS基因供体材料,分别与产量较高的密阳23、秀水123和沪稻55进行杂交,并利用3个杂交群体早世代籽粒垩白特性、直链淀粉含量(AC)及功能标记(CAPS/Spe I)进行高RS水稻辅助选择育种。结果表明,籽粒的垩白特性与RS含量有很高的关联性,早世代通过垩白度和垩白粒率可以淘汰大部分低RS含量单株。利用控制水稻RS合成主效基因sbe3-rs上的一个功能标记(CAPS/Spe I)确定sbe3-rs基因型纯合的高RS单株,经连续自交和辅助选育,最终培育了3个兼具功能性、高产和优质的高RS水稻品系RS23、RS123和RS55。本研究首次提出利用对杂交群体早世代籽粒垩白特性挑选淘汰大部分低RS含量单株,同时结合分子标记辅助选择显著提高选择效率和准确度,建立了高RS水稻品种选育的高效分子标记辅助选择育种体系。本研究可为开展高RS育种提供新的理论依据和基础材料。     

甘蓝型油菜显性核不育系的分子标记辅助选择

为探究分子标记BE10对甘蓝型油菜显性核不育系选育中的作用,本研究以甘蓝型油菜核不育系为材料,利用分子标记BE10,检测甘蓝型油菜显性核不育系的自交分离群体和纯合型不育株,并通过田间育性观察,验证分子标记BE10辅助选择的可靠性。结果表明,基因型为MS5~aMS5~b的可育株自交,其后代的育性表现为3∶1(可育∶不育),基因型分离结果为1MS5~aMS5~a:2MS5~aMS5~b:1MS5~bMS5~b。选取可育株自交,三分之二的单株后代分离比例与上一世代相同,三分之一的单株后代群体因携带纯合型的MS5~a而表现为100%可育。利用分子标记BE10的辅助选择,不仅能鉴定出后代群体是否有MS5~b不育基因,提高不育系的选育效率,还能从育性表现为3∶1(可育∶不育)的自交系中筛选出纯合型不育株;结合无性繁殖技术,用纯合型不育株的无性系与临保系生产全不育系,可有效提高全不育系的纯度,为杂交种选育和杂交种子生产提供了新思路和新途径。     

垂体腺苷酸环化酶激活多肽基因(PACAP)G3909A突变对秦川牛部分生长性状的影响

利用PCR-SSCP技术检测垂体腺苷酸环化酶激活多肽基因（PACAP）在257头秦川牛（Bos tarurs）群体中的多态性,并构建最小二乘分析模型,分析基因型与部分生长性状的相关性。结果表明,在该基因3909bp处发生G/A突变,基因型检测结果共发现3种基因型,AA、AB和BB,A和B等位基因的频率分别为0.5992和0.4008。卡方检测结果显示该位点在所检测秦川牛群体中处于Hardy-Weinbery平衡状态。方差分析结果显示：体斜长,AA、AB和BB基因型个体之间差异均达到极显著（P〈0.01）;体高,AA和AB基因型个体极显著高于BB基因型个体（P〈0.01）,AA基因型个体显著高于AB基因型个体（P〈0.05）;体重,AA和AB基因型个体极显著高于BB基因型个体（P〈0.01）;胸围,AA基因型极显著高于BB基因型个体（P〈0.01）,AA基因型个体显著高于AB基因型个体（P〈0.05）,AB基因型个体显著高于BB基因型个体（P〈0.05）;胸宽,AB基因型个体显著高于BB基因型个体（P〈0.05）;而其它性状差异均不显著。该位点可能是影响秦川牛体斜长、体高、体重、胸围和胸宽的主效QTN或与之紧密连锁,可作为秦川牛选育的侯选分子标记。     

Effects of pollination distance on reproduction and offspring performance in Hypochoeris radicata: Experiments with plants from three European regions

Fragmentation of habitats has resulted in increased inbreeding for many plant species, while the introduction of foreign seed material for ecological restoration has resulted in crosses between plants from distant populations. Both processes may reduce plant fitness and increase the risk of extinction. Variation in the expression of inbreeding and outbreeding depression has been found among different genotypes and among populations, but little is known about large scale geographical patterns within species. We studied the effects of cross-proximity on seed production and offspring performance in the perennial meadow plant Hypochoeris radicata (Asteraceae) from five populations in each of three European regions (Bohemia in northwest Czechia, Northern Hesse in central Germany, and Salland in the central Netherlands). Five artificial cross types were conducted with varying proximity of mates: selfing (self), within family crosses (WF), within population crosses (WP), between population crosses (BP), and between region crosses (BR), and the offspring were grown in a common garden. Independent of the region of origin of the maternal plant, selfing, WF and BP crosses resulted in lower seed set and germination than WP crosses, indicating partial self-incompatibility, inbreeding depression and reduced performance in the F1 progeny resulting from outbreeding. However, crosses between regions resulted in similar seed set and germination as within population crosses. For late traits, the effects of inbreeding and interpopulation crosses differed among regions. WP crosses exhibited the highest survival, flowering and multiplicative fitness only in progeny from Czech maternal plants. Our results suggest that the sensitivity of populations to introgression may vary among regions and that outbreeding depression does not necessarily increase with interpopulation distance. However, the current study investigated only effects in the F1 in a common garden and outbreeding depression may be stronger in the F2 and in field populations.     

Management of Vicia faba genetic resources: changes associated to the selfing process in the major, equina and minor groups

Conserving Vicia faba germplasm as a pure line collection requires reliable information of the selfing process. Previous knowledge about the effects of selfing was elaborated on the context of new data. In our study we increased the number of entries, 95 entries from the major, equina and minor groups were studied. The selfing process has been quantified by means of univariate as well as multivariate techniques. Effects of selfing on floral, yield and yield distribution traits were investigated by comparing two levels of selfing in open pollination conditions and in cages to exclude insects. Univariate analysis shows that selfing process results in plants with lower seeds per plant, seeds and ovules per pod and pod length. As selfing progressed there was change in yield distribution traits, the number of the lowest pod bearing node, the number of nodes between the first flower and the first pod increase and the number of nodes with pods decreases. Multivariate analysis indicates that: a) self-pollination profoundly influences plants performance and the three levels of selfing studied are clearly different; b) There is continuum pattern of change from one level of selfing to the another; c) The main characteristics that contributed to the separation among the levels of selfing varies with the botanical group. d) There was no significant contribution to the discrimination among levels of selfing of number of seeds per plant in the major group. Our results are relevant to the management of faba bean germplasm collections and enhance the formulation of integrated strategies of faba bean germplasm multiplication.     

Limited genotype- and ploidy-related variation in the nutritive value of perennial ryegrass (Lolium perenne L.)

Abstract

Water-soluble carbohydrates and fibre fractions are important traits that influence forage utilization by the ruminant. Little is known about the quality variation among perennial ryegrass genotypes within the same maturity group or between near-isogenic diploids and tetraploids. The current study was carried out in the form of two experiments on two successive years (2006–2007) in three sites in Northern Germany. The main aim was to investigate the variation in nutritive value that could be attributed to differences in maturity among 20 intermediate heading perennial ryegrass genotypes or to differences in ploidy between near-isogenic diploids and tetraploids. Results of the first experiment revealed significant variation among the 20 tested genotypes in the investigated quality parameters that were consistent with the discovered variation in the maturity of the genotypes determined in terms of their Mean Stage by Count (MSC). In the second experiment, few but consistent significant differences were detected between near-isogenic diploids and tetraploids. The tetraploid derivatives had always significantly higher water-soluble carbohydrate content and lower neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) than their near-isogenic diploid parents.     

Identification of intra-accession genetic diversity in selfing crops using AFLP markers: implications for collection management

Germplasm conserved as seeds in genebanks requires regular regeneration. In this process, selection and genetic drift may cause loss of genetic diversity from accessions. In the case of selfing crops, separation of distinct lines into different accessions may be an efficient strategy to avoid these negative effects. In order to evaluate the applicability of this method for collection management, knowledge about the level of intra-accession genetic diversity is required. By means of AFLP analysis intra-accession variation was investigated in two cultivars, two landraces and two wild populations of ex situ conserved barley germplasm. In the total sample of 216 individuals analysed (36 per accession), 22 genotypes were observed based on 104 polymorphic loci. The number of genotypes detected ranged from 1 to 3 per accession, except for a Nepalese landrace that revealed 12 genotypes. An UPGMA cluster analysis grouped the genotypes unambiguously into the accession they belonged to and genotypes within accessions were generally found to be closely related. In order to determine the repeatability of the results obtained, 11 individuals belonging to 4 genotypes from the Nepalese landrace were scored for a second set of AFLP markers. Matrices of genetic distances calculated for the two AFLP datasets were found to be highly correlated (r = 0.9346, P < 0.001). Separation of genotypes into different accessions was considered a relevant option only for the Nepalese landrace. Analysis of molecular variance indicated that this accession could be well divided into 8 distinct lines. Further implications of the results for genebank practices are discussed.     

山东省土地利用结构时空变化及其驱动机制分析

基于山东省1987~2003年统计资料和土地详查与变更调查数据,研究揭示了山东省近17年来土地利用结构信息熵和均衡度的时空变化,并在此基础上进一步探讨了土地利用结构信息熵和均衡度动态变化的驱动机制。结果表明:17年来,山东省土地利用结构信息熵和均衡度的变化经历了增加→减少→缓慢增加的变化过程,总体趋势是各土地利用类型的面积占土地总面积的比例差别逐渐缩小,土地利用结构的均质性逐渐增强;土地利用结构的信息熵和均衡度具有空间分异规律,从东部沿海向西部内陆递减,总体而言,东部半岛丘陵区的信息熵和均衡度值>中南部山地丘陵区>西部、北部平原区;自然因素、人口变化、经济因素和政策调控等是影响土地利用结构信息熵和均衡度时空变化的主要驱动因子。     

Reproductive ecology of the warthog Phacochoerus aethiopicus and its significance for management in the Eastern Selous Game Reserve,Tanzania

The study examines the reproductive potential of the warthog Phacochoerus aethiopicus in the eastern Selous Game Reserve, Tanzania, and establishes the recruitment pattern of the population. The methods involved animal collection and field observations.Results showed that female warthogs reached sexual maturity at about two years of age. There was a fairly high reproductive rate, with 87% of sexually mature females producing an average of 2·6 hoglets each a year. Breeding occurred in April and May, farrowing in September, October and November. This suggested a gestation period of about five months. Females of 4 and 5 years of age were found to be more productive than either younger or older ones. Pre-natal sex ratio was 1:1, but post-natal deviated from unity. Mortality was highest in younger and very old animals.The importance of data on reproductive ecology to efficient game management is stressed.     

Effectiveness of some management procedures for seed regeneration of plant genetic resources accessions

Procedures for seed regeneration of plant genetic resource accessions were investigated in terms of their effect on the variance effective population size and the probability that the initial allelic diversity is maintained after 10 and 20 cycles of regeneration. Four regeneration systems were compared: a bulk system (BL) where seeds are collected and treated in bulk, a partial sampling system (PS) where seeds are collected from not all, but some plants in the population with an equal number of offspring being raised from each sampled plant, a single seed system (SS) where accessions are regenerated so that each plant leaves one progeny, and the biparental mating system (BP) of Gale & Lawrence (1984) where plants are pollinated in pairs with one offspring being raised from each of the paired plants, or two offspring from one of the paired plants. It was shown that the relative efficiency of the four systems largely depends on the rate of selfing and that differences in the effective population size of the systems increase with increasing rates of selfing. The SS system gave by far the largest effective population size in regenerating the seed of moderately or highly selfing species. Although the BP system gave the largest effective size for outcrossing species, the SS system, when combined with selfing, gave a much larger effective size. The BL and PS systems were in no case the most effective. Of these two, PS system with a sampling fraction of 50% was as effective as BL, but less effective with a sampling fraction smaller than 50%. Calculations of the maintenance of the allelic diversity, however, revealed that differences between the systems are not appreciably large unless the accessions are regenerated over 10 or more cycles with 50 or fewer plants.     

Influence of growth temperature on the amounts of tocopherols, tocotrienols, and gamma-oryzanol in brown rice

Brown rice is a valuable source of lipid-soluble antioxidants including ferulated phytosterols (i.e., gamma-oryzanol), tocopherols, and tocotrienols. To evaluate the impact of temperature on the accumulation of these compounds, seeds from six different rice lines grown to maturity in replicate greenhouses in Gainesville, FL, were analyzed. The lines represented Oryza sativa indica, O. sativa japonica, and Oryza glaberrima of different origins. Temperatures were maintained near ambient at one end of each greenhouse and at approximately 4.5 degrees C above ambient at the other end. gamma-Oryzanols, tocopherols, and tocotrienols were extracted from whole seed (i.e., brown rice) and analyzed by HPLC. Tocotrienols and tocopherols varied widely between lines but changed only slightly with respect to temperature. In general, the proportions of alpha-tocotrienol and/or alpha-tocopherol increased at elevated temperature, whereas gamma-tocopherol and gamma-tocotrienol decreased. Six gamma-oryzanol peaks, identified on the basis of absorbance maxima at 330 nm and HPLC-mass spectrometry, were quantified. The most abundant component was 24-methylenecycloartanyl ferulate, present at 40-62% of total. Its levels increased 35-57% at elevated temperature in five of six lines, accounting for most of the change in total gamma-oryzanol. The results suggest that the physiological action of individual ferulated phytosterols should be investigated because their relative proportions in gamma-oryzanol can change.     

主要农田生态系统氮素行为与氮肥高效利用研究

氮肥在我国农业生产中发挥了重要作用 ,但氮肥的不合理施用也带来了一些负面影响 ,氮肥施用不合理、利用率低 ,不仅导致氮素的大量损失、造成了浪费 ,而且还对生态环境产生不良影响 ,使农田氮素成为重要的污染源之一 ,同时过量施用氮肥还严重影响了农产品品质。针对氮肥施用存在的问题 ,国内外已经开展了大量的基础研究。国家自然科学基金委员会多年来也资助了与农田生态系统氮素行为与氮肥高效利用研究相关的一些课题 ,为进一步系统开展本领域的综合研究奠定了基础。 2 0 0 2年 ,国家基金委针对氮肥施用中存在的科学问题设立了题为主要农田生态系统氮素行为与氮肥高效利用的重大项目 ,以期在国内外研究基础上 ,围绕农田生态系统氮素行为与氮肥高效利用 ,对我国主要农田生态系统中氮素的行为、作物高效利用氮肥的生理和遗传机制及调控作物高效利用氮肥的理论与方法等前沿科学问题开展跨学科的系统研究 ,为改变我国氮肥利用率低的局面提供理论依据。     

Reduced seed production, inbreeding, and pollen shortage in a small population of a threatened tree, Magnolia stellata

We investigated how genetic factors and pollen shortage affect seed production in a small population of Magnolia stellata, a threatened insect-pollinated tree. We used microsatellite and manual pollination techniques, and compared a small population to a large one. Compared to the large population, the small population showed low allelic variation and had an F_IS significantly greater than 0 in adults, indicating that genetic deterioration, including genetic drift and inbreeding, may have occurred in adults. Manual self-pollination lowered seed production relative to manual cross-pollination to a different extent between populations: δ (the magnitude of inbreeding depression due to self-fertilization) was lower in the small population than in the large population. However, under natural pollination, the estimated embryo mortality rates after ovules self-fertilized were similar between the two populations because the primary selfing rate was higher in the small population. The ovule mortality rate due to pollen shortage and that due to factors independent of pollen shortage and selfing were both approximately 10% higher in the small population, suggesting that pollen transfer may have decreased and genetic deterioration effects may have increased in that population. These factors reduced seed production in the small population (female reproductive success = 0.3%) compared to the large population (2.6%). Our results suggest that seed production in the small population of M. stellata is strictly limited by elevated pollen shortage, selfing, and genetic deterioration in adults, which accelerate the risk of extinction.