Evaluation of seed production in a first-generation seed orchard of Chinese pine(Pinus tabuliformis)

We evaluated seed production in a first-generation orchard of Chinese pine(Pinus tabuliformis) during the crucial transition period from first generation to advanced generations.Clones varied significantly in all traits related to seed production.Repeatability of these traits ranged from 0 to 0.96.Seed production per ramet(SPPR),seed producing index(SPI),the number of relative female strobili(RFS),the number of scales,and the number of ineffective scales had comparatively high repeatability at 0.86,0.87,0.89,0.96,and 0.91,respectively.Correlation analysis showed that SPPR was greatly influenced by RFS and by the number of full seeds per cone.Finally,we showed that SPI was the best predictor of the seed-producing ability of clones.Our findings will assist seed orchard managers in effectively predicting and improving seed production of Chinese pine seed orchards.     

我国松树种子园结实规律的研究进展

对松树种子园球果与种子产量变异、空间分布规律、性状变异、产量预测、败育分析、结实量与生长性状的关系等方面的研究状况作了较为系统的综述;并对今后的发展提出了展望。     

Juvenile radiata pine clonal seed orchard management in Galicia (NW Spain)

A juvenile radiata pine clonal seed orchard (Pinus radiata D. Don) in Sergude (northwestern Spain), comprising 57 clones, was evaluated for fertility, offspring diversity and genetic drift during 4 years. Flower and fruit production was used to asses clone fertility in the orchard. Fertility variation measured as “sibling coefficient” was found to be an average of 1.5, having high genetic diversity (0.99) and low coancestry (0.013). The clones varied in fertility from year to year. Effective population size in the orchard was between 35 and 40, indicating that between 60.30 and 69 %, the clones contributed effectively to seed yield. One way to improve seed yield in the orchard is by increasing the effective population size. Thinning and pruning highly reproductive clones of gibberellin application might be useful in increasing effective population size. The orchard’s parental balance showed consistent improvement over time. Cone and seed characteristics were also investigated. The results showed that significant genetic variation exists among clones for cone width and length; total, sound and empty seed number; as well as 100 seed weight. The seed orchard is still in a juvenile phase; moreover, the broad-sense heritability and variation data obtained in this study could be very valuable in the management practices of the existing radiata pine clonal seed orchard and can be also used for better planning of advanced generation of clonal seed orchards in Spain.     

Effects of crown-pruning on seed and pollen cone production in two lodgepole pine seed orchards in British Columbia

The effects of top pruning on subsequent seed and pollen cone production in lodgepole pine (Pinus contorta Dougl.) grafted clones in two seed orchards were evaluated. In the older orchard (14 years old), three pruning regimes were applied: an untreated control, a moderate pruning where 25% of the crown was removed and a severe pruning where 40% of the crown was removed. In the younger orchard (ten years old), only a control pruning and a severe pruning (50% of crown removed) were applied. Five-year seed cone production was lower in treated ramets compared to controls in both orchards. However, when cumulative seed cone yields were adjusted for reduced tree heights after pruning, differences were no longer significant in the older orchard. Strong clonal variation was observed in seed cone yields in both orchards. Pollen cone development was less variable among treatments in the older orchard. In the younger orchard, controls consistently produced heavier pollen crops. Pruning recommendations for similar orchards are made and results discussed for reducing the impacts of losses in seed cone yields.Deceased     

Realized genetic gains observed in a first generation seedling seed orchard for jack pine in New Brunswick,Canada

Jack pine seedlots collected from a seedling seed orchard owned by J.D. Irving Limited (JDISSO) were compared in a block-plot genetic gain test on four sites in New Brunswick, Canada. Three seedlots representing different genetic quality of the orchard were included: before rogueing (UNR), following the first rogueing (1STR), and following the second rogueing (2NDR). Two stand seedlots were included to represent an average unimproved commercial seedlot (UC) for comparison. Individual tree growth and stem straightness were recorded up to age 15 (one-third rotation age). For individual tree growth, there was no strong evidence of better performance of the UNR over the UC, but the 1STR and 2NDR grew much faster. For volume per hectare, all the JDISSO seedlots outperformed the UC. The realized gains per hectare were higher than those on individual tree basis, but both increased with rogueing time and decreased with age. Improvement in stem straightness was also significant for all the orchard seedlots. The realized genetic gains were generally comparable to the respective predicted ones from the family tests. Analyses of individual sites indicated that the realized gain varied greatly with site, especially for growth traits. Deploying good seedlots to better sites would result in more volume gains. Overall, results of this study indicate the efficiency of the seed orchard procedure for jack pine.     

马尾松一代无性系种子园营建与丰产技术研究

本研究历经“六五”选优,“七五”建园与“八五”投产,长达工5年之久的科学研究与生产实践,比较系统地阐述了马尾松一代无性系种子园的营建、管理与种子丰产技术。“八五”期间种子园开始生产种子,产量逐年上升,1995年大面积平均每公顷产量为9.375kg,最高小区平均每公顷产量达27.825kg,属于马尾松投产初期高产种子园之列。种子园混系种子质量优异,5年生子代林材积增益比对照大41.4％。种子园的建成与投产,可为速丰林建设提供优质良种。     

Female fertility variation in mature Pinus sylvestris clonal seed orchards

Abstract

Female fertility is the basis for the output of seeds from clonal orchards and its variation is of major interest for the economics and biology of seed orchards, especially for the efficiency and diversity of seed orchard crops. Assessments of female fertility variation in 10 mature (>15 years old) seed orchards of Scots pine (Pinus sylvestris L.) were evaluated and compared. Depending on the individual orchard, fertility variation for each clone was assessed in slightly different ways, e.g. number of strobili, cones, seeds or litre of cones per ramet. Assessments in five of the orchards were made over consecutive years. The main result was that the clonal variation in mean female fertility per surviving ramet was lower than expected from the literature; the Kang–Lindgren sibling coefficient (Ψ) within individual years averaged 1.35. The variation between ramets within clones and years was of similar magnitude as that between clones. Clone by year interactions were noticeable, but were slightly lower than the variation between as well as that within clones in individual years. There was considerable variation in the variance components between years. The limited variation in female fertility indicated that it should not be a selection criterion when selecting clones for a seed orchard. Furthermore, it will not result in large differences between clones in seed set or large reductions in gene diversity in productive Scots pine seed orchards.     

Balancing seed yield and breeding value in clonal seed orchards

Seed orchards should produce seeds that are both abundant and of high genetic value. This study suggests methods to achieve such a compromise and study their efficiency. The methods were applied on data obtained from 41 seed orchard clones of Scots pine from mid-Sweden. The value of the seed orchard crop was set as a function of its breeding value, the amount of seeds produced and their gene diversity, measured as the effective number of clones. The proportion of ramets of different clones that maximized this value was regarded as the optimum for deployment of the clones in a seed orchard. The results were compared with truncation selection for breeding value, truncation selection for clone benefit (the product of seed production and breeding value) and linear deployment (where ramets are deployed linearly in relation to breeding value). The influence of two parameters was studied: the relative importance of breeding value for seed value and the size of the penalty for reducing the value of the seed crop with respect to lost gene diversity. The conventional wisdom is to select the clones with the highest breeding values, but that turned out to be the most inferior alternative studied. Clone benefit truncation provided a good approximation to optimal benefit for cases, where the effective number was low and dependence of breeding value limited.     

Advanced generation seed orchards’ turnover as affected by breeding advance,time to sexual maturity and costs,with special reference to Pinus sylvestris in Sweden

Abstract

The effect of various biological, genetic, economic and management factors relevant to advanced generation seed orchard establishment was investigated using numerical estimates for Scots pine (Pinus sylvestris L.) in Sweden. Factors considered were planting density, rate of genetic advance in the breeding population, timing of first seed collection, seed value, seed production cost (stratified to establishment, annual management, cone harvest and seed extraction), orchard rotation age and contamination level. The developed model demonstrated its utility in studying and evaluating various economic and biological options associated with advanced generation seed orchard establishment/turnover. Sensitivity analyses demonstrated the robustness of the developed model through various arbitrarily changes in genetic gain advances, establishment, management and seed production, particularly those associated with cone harvests from upper crown and costs. The Swedish Scots pine case study produced results supporting faster turnover of seed orchard generations (30 vs 40 years) with shorter orchard lifespan (early start of seed cone after 8 years vs 15 years) delivering higher gain through minimizing the genetic gain differential between the breeding and production populations and allowing the capture of this gain for inclusion in the seed orchards. Orchard planting densities of 400 and 600 grafts per hectare produced similar results with marginal differences, and the latter was recommended for future orchard establishment.     

Cost-benefit analysis of using orchard or stand seed in Scots pine sowing,the case of northern Finland

A cost-benefit analysis of orchard seed versus seed from existing natural stands is presented for the scenario of direct sowing of Scots pine (Pinus sylvestris L.). The differential benefits of orchard seed are seed quality and improved yield due to genetic gain. These benefits are expected to further reduce the total cost of orchard seed. Seedlings from seed orchard seed had 11% better survival rate (p < .001, the best clone over 17%, p < .010) than seedlings from local stand seed. This was observed in a case study of 15 young seeding trials located in Central and North Finland. Expected yield improvements for stands established with orchard seed were obtained from local progeny test results, and they were further simulated on tree growth using the MELA forest simulation program. The cost-benefit analysis showed that, with a 7% yield improvement and a 15% better seed quality, the net cost of orchard seed was less than that of stand seed (discount rate 3%).     

杉木第二代种子园亲本性状遗传变异研究

以沙县官庄国有林场22年生的杉木第2代种子园为研究对象,对220个无性系进行系统测定,探讨了无性系生长、形质和结实性状的遗传变异规律,结果表明:生长性状、形质性状和结实性状在无性系间的差异达到极显著水平,而且无性系的重复力值均较大;从220个无性系中综合筛选出丁74等35个优良无性系,各优良无性系生长量大、结实性状良好,22年生时的平均树高、胸径、材积值分别高达17.56 m、33.60 cm和0.803 35 m3,分别大于种子园中调查的220个无性系平均值的20.36%、17.73%和57.32%,综合性状表现优良,可用作高世代种子园建园材料和杂交育种的亲本材料。     

马尾松第一代改良无性系种子园建园材料选择

以福建省漳平五一国有林场马尾松第一代无性系种子园为研究群体,在对园内无性系及其子代家系测定数据分析基础上进行无性系再选择,重建改良代种子园。结果表明,子代生长量与当代无性系产籽量和雌雄球花量,在家系与无性系水平上差异极其显著,且不同程度受遗传控制,具有一定选育潜力。采用综合评定和独立淘汰相结合的方法,能实现性状兼优的无性系再选择。以一代(CK1)为对照,从160个无性系中再选择30个无性系建立的改良代种子园育种效果显著,其遗传增益估值,8年生子代材积提高10.9%,产籽量和雌、雄球花量分别提高49.1%、18.9%、7.6%;以母树林混合种(CK)为对照,2个选择阶段,8年生子代材积累计遗传增益估值18.1%。     

Variability in seed traits and genetic divergence in a clonal seed orchard of Dalbergia sissoo Roxb.

The variations in seed and pod traits, genetic superiority and genetic divergence were evaluated for a Clonal Seed Orchard (CSO) of Dalbergia sissoo Roxb. at Bithmera, India consisting of 20 clones from different agro-climatic conditions of four northern states (Uttar Pradesh, Uttarakhand, Haryana and Rajasthan). The seeds and pods of various clones in the orchard exhibited significant variability in size, weight and other characters. Significant positive correlations were observed between seed length and seed width (p<0.05), seed length and seed thickness (p<0.01), seed length and seed weight (p<0.01), seed thickness and seed weight (p<0.01), seed length and germination value (p<0.05). The genetic parameters for seed and pod traits also showed a wide range of variations in the orchard. Heritability values were found to be over 50 percent for most of the seed and pod traits. Seed weight, seed length and seed thickness showed high heritability values coupled with maximum genetic gain for these characters. Ward’s minimum variance dendrogram of clones of D. sissoo showed three distinct clusters; cluster 1 was the largest with 12 better clones whereas cluster 2 and 3 consisting of seven moderate clones and one poor clone, respectively. Mean cluster values showed sufficient variation among the clusters for seed weight, germination value and seed length. The possible hybridization between best clones of cluster 1 to the disease resistant clone of cluster 2 (resistant against deadly Gandoderma lucidum root rot disease of D. sissoo) is also suggested for further breeding programmes of the species. The deployment of clone 194 (better performed and disease resistant) is also recommended in future plantation programmes of D. sissoo in northern India.     

Clonal variations in cone,seed and nut traits in a Pinus koraiensis seed orchard in Northeast China

Korean pine(Pinus koraiensis Siebold Zucc.)in Northeastern China has been genetically improved to increase seed yields in addition to timber.To assess seed yield variability and select highly productive clones,14 cone,seed and nut traits were measured and analyzed.Variance analysis showed that all clones were significantly different in various traits(P0.01).Phenotypic coefficients of variation and repeatability of traits ranged from 9.1 to34.4% and from 27.5 to 97.7%,respectively.Except for the cone layer and cone seed numbers,the other traits were positively or negatively correlated.Three principal components were identified.Seed and nut traits were the most important traits in the first principal component,and cone traits more important in the second.Using correlation and principal component analyses,cone number and other traits were selected to evaluate materials.Twenty-two clones were selected using a selection rate of 10% based on cone number independently or other combined traits.The genetic gain for different traits ranged from 6.2 to 24.3%.The selected elite clones can supply seedlings for reforestation and the selection method can provide a theoretical basis for selection in other conifer species.     

Effects of gibberellin A<Subscript>4/7</Subscript>, 6-benzylaminopurine and chlormequat chloride on the number of male and female strobili and immature cones in Chinese pine (<Emphasis Type="Italic">Pinus tabuliformis</Emphasis>) with foliar sprays

Three kinds of plant growth regulators, gibberellinA 4/7 (GA 4/7 ), 6-benzylaminopurine (BA), and chlormequat chloride (CCC), were evaluated for their ability to promote strobilus and cone production in a Chinese pine (Pinus tabuliformis Carr.) clonal seed orchard. Treatments (0, 250, 500, or 1000 mg L -1 ) were applied during three periods (June- July, July-August and August-September) in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed...     

Cone traits of jack pine and black spruce in young seedling seed orchards

The number of fertile and infertile scales, filled and empty seeds, cone volume, seed efficiency and the incidence of insect and disease damage to seed were evaluated for seven jack pine (Pinus banksiana Lamb) and six black spruce (Picea mariana [Mill.] B.S.P.) seedling seed orchards in northern Ontario, Canada. On average, the seed potential of jack pine and black spruce cones was 50 and 82 seeds, respectively. Cone volume and the number of fertile scales were under strong genetic control and well correlated with one another for both species. Seed efficiency values were high for jack pine (60%) but poor for black spruce (24%). The incidence of seed insect damage was less than 2.5% for both species and nil for seed diseases.     

广东韶关马尾松种子园遗传多样性分析

从210个随机引物中筛选出的16个引物,共检测到118条带,其中多态性带95个,总多态位点比率为80.37%,充分说明了马尾松无性系间遗传背景的复杂性和多样性。采用Nei指数计算的建园无性系马尾松有效等位基因数平均值为1.3447,总基因多样性为0.2445,遗传多样度(h)平均值为0.2445,Shannon′s信息指数(I)平均值为0.3558,与一些松柏纲植物的RAPD数据资料相比,马尾松的遗传多样性处于较高水平,显示出该无性系马尾松种子园内各马尾松的遗传基础较宽,具备营建出遗传品质好、遗传多样性高、稳定性好的马尾松人工造林的能力,能满足林木育种的需要。     

Reduction of pollen contamination in Scots pine seed orchard crop by tent isolation

This study examined the differences in mating system between indoor versus outdoor Scots pine (Pinus sylvestris L.) seed orchard using DNA markers. By analyzing the paternities in seed crops from isolation tents, we found a significant reduction in contamination rate, from 23% in the outdoor open blocks to 0% inside the tents. Increase in selfing rate and a decrease in genetic diversity in the crops were also observed inside the tents. These undesirable effects can be mitigated to some extent by the supplementation of extra pollen genotypes, e.g. selfing rate decreased from 14.4% to 6.6% and the effective number of fathers increased from 6 to 11.4 in the tents without and with supplemental mass pollination, respectively. Our study showed that tent isolation may become an effective rescuer for seed orchards where pollen contamination is severe.     

Mating patterns in an indoor miniature <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> seed orchard as revealed by microsatellite markers

To evaluate the practical application of an indoor seed orchard, we compared the seed production, final germination rates and mating patterns of potted Cryptomeria japonica D. Don clones in two miniature seed orchards: one in a glasshouse and the other outdoors. There was no statistically significant difference in total seed production between the orchards (P = 0.275, ANOVA). However, the final germination rate of seeds produced in the indoor orchard was significantly lower than that of seeds produced in the outdoor orchard (P < 0.01, Wilcoxon test). The average self-fertilization rate was higher in the indoor orchard (27.2%) than in the outdoor orchard (5.6%), and this parameter was strongly associated with the reduced final germination rates of the seeds harvested in the glasshouse. Pollen contamination was considerably lower in the indoor seed orchard (48.9% in the outdoor seed orchard and 4.4% in the indoor seed orchard). χ² tests indicated that the paternal contributions of each constituent clone differed significantly in both orchards (P < 0.001 in both cases). The strong variations in paternal contributions among indoor orchard clones was significantly correlated with their respective pollen production capacities (Spearman ρ = 0.693, P < 0.001). To reduce the high self-fertilization rates, we recommend the use of orchard clones with similar pollen production capacity in indoor seed orchards.     

成年杉木种子园提质改造无性系选择及容器苗培育技术研究

为提高20世纪80年代后期营建的1.5代杉木种子园遗传品质和种子产量,以子代材积增益、当代种子产量均高为标准,选择用于成年种子园提质改造的优良无性系。经综合评价,选择出了靖大30、靖大35、广洋45等可用于杉木成年种子园提质改造的优良无性系20个。采用随机区组设计的方法开展优良无性系容器育苗试验。结果表明:以高度17 cm、直径19 cm规格的容器,按体积比配置70%泥炭土、25%黄心土、5%珍珠岩的混合基质培育容器砧木苗,在砧木保留3轮底枝的部位进行嫁接,切接或舌接法培育2年生容器嫁接苗成活率达90%以上、苗高达93 cm以上。