Temporal analysis of breeding structure in jack pine (Pinusbanksiana Lamb.)

Thomas P. Snyder; Dale A. Stewart; Ann F. Strickler

doi:10.1139/x85-188

Temporal analysis of breeding structure in jack pine (Pinusbanksiana Lamb.)

Canadian Journal of Forest Research ◽

10.1139/x85-188 ◽

1985 ◽

Vol 15 (6) ◽

pp. 1159-1166 ◽

Cited By ~ 14

Author(s):

Thomas P. Snyder ◽

Dale A. Stewart ◽

Ann F. Strickler

Keyword(s):

Seed Germination ◽

Temporal Analysis ◽

Jack Pine ◽

Outcrossing Rate ◽

Fixation Index ◽

General Increase ◽

Mendelian Segregation ◽

Selection Hypothesis ◽

Natural Stand ◽

Breeding Structure

Outcrossing rates for 10 pollination years were estimated for a natural stand of jack pine using allozymic markers at the Mdh-2 and 6-pgd-1 loci. Outcrossing rate estimates showed a general increase with time since pollination. Population fixation index values for the progeny decrease with time since pollination, showing an increasing proportion of heterozygous progeny. These increases parallel those observed for jack pine, lodgepole pine, and alpine ash by other investigators, suggesting selection against inbred progeny may be occurring during the retention of the seed in the serotinous cones. Evaluation of the selection hypothesis by regression of the proportion of heterozygous progeny and of seed germination on year of pollination showed significant linear decreases in germination over a 10-year period for only one of eight trees. This was not accompanied by an increase in the proportion of heterozygous progeny. Apparent deviations from normal Mendelian segregation were noted at the Mdh-2 locus in two trees.

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Comparative Growth and Development of Planted and Natural Stands of Jack Pine

The Forestry Chronicle ◽

10.5558/tfc64320-4 ◽

1988 ◽

Vol 64 (4) ◽

pp. 320-328 ◽

Cited By ~ 8

Author(s):

P. S. Janas ◽

D. G. Brand

Keyword(s):

Pinus Banksiana ◽

Initial Density ◽

Jack Pine ◽

Growth And Yield ◽

Large Individual ◽

Individual Tree ◽

Natural Stand ◽

Tree Form ◽

Stem Quality ◽

Natural Stands

This study compares growth yield, and stem quality differences at age 21 between plantations spaced at 2.13 × 2.13 m (2204 stems/ha) and 4.27 × 4.27 m (548 stems/ha), and a nearby natural jack pine stand of identical age (initial density of 29 800 stems/ha). Merchantable volume/ha was greatest at the 2.13 m spacing, followed by the less dense plantation and natural stand. Total volume/ha (trees > 1.3 m height) was also greatest in the 2.13 m plantation, followed by the natural stand and the 4.27 m plantation. Individual tree mean merchantable volumes decreased with increasing density. Height growth decreased with increasing density. Height 4.27 m plantation relative to the 2.13 m plantation. Stem quality of the natural stand was markedly better than in both plantations. A comparison of an older natural stand and a plantation in the same area suggests that superiority of tree form of denser natural stands will continue through to rotation. High mortality in the natural stand was largely the result of snow and ice damage which caused patchy and irregular stocking. These results imply that widely spaced plantations of unimproved jack pine will produce large individual tree sizes, but at the expense of quality. Key words: Pinus banksiana, plantations, natural stands, stem quality growth and yield, stand density, mortality, spacing, silviculture.

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Genetic structure and variability in jack pine populations: effects of insularity

Canadian Journal of Forest Research ◽

10.1139/x92-255 ◽

1992 ◽

Vol 22 (12) ◽

pp. 1958-1965 ◽

Cited By ~ 13

Author(s):

Sylvie Gauthier ◽

Jean-Pierre Simon ◽

Yves Bergeron

Keyword(s):

Genetic Structure ◽

Regional Scale ◽

Fire Regimes ◽

Jack Pine ◽

Fixation Index ◽

Significant Heterogeneity ◽

Island Populations ◽

Selective Pressures ◽

Expected Heterozygosity ◽

Hardy Weinberg Equilibrium

To determine the effects of insularity on the genetic structure and variability of jack pine (Pinusbanksiana Lamb.) populations at a regional scale, stands from two different landscapes were studied: two islands in a lake and two mainland areas. The two landscapes have been affected by different fire regimes. The genetic structure and variability of the four populations were analyzed using cellulose acetate gel electrophoresis of 11 enzyme systems. The analysis of 22 loci showed an average polymorphism of 60.0%, a mean of 2.3 alleles per locus, a mean of 1.185 effective alleles per locus, and an observed level of heterozygosity of 0.171. The Fis values (i.e., fixation index of individuals relative to their population) for all but two loci indicated an excess of heterozygotes compared with the expected numbers under Hardy–Weinberg equilibrium. The genetic differentiation among populations was weak (Fst = 0.018). There were no significant differences among the four populations for five genetic parameters (mean number of alleles per locus, mean number of effective alleles per locus, percentage of polymorphic loci, and observed or expected heterozygosity). Although the allelic frequencies were homogeneous between island populations, a significant heterogeneity in allele frequencies was observed between mainland populations. The results suggest that gene flow in island populations is sufficiently high to maintain a level of genetic variability similar to that found in mainland populations and to counteract the effect of isolation and differential selective pressures resulting from different disturbance regimes.

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Inferring mating system parameters in forage peanut, Arachis pintoi, for Brazilian Amazon conditions

Acta Amazonica ◽

10.1590/1809-4392201900200 ◽

2019 ◽

Vol 49 (4) ◽

pp. 277-282 ◽

Cited By ~ 1

Author(s):

Jônatas Chagas de OLIVEIRA ◽

Polinar Bandeira RUFINO ◽

Hellen Sandra Freires da Silva AZÊVEDO ◽

Adna Cristina Barbosa de SOUSA ◽

Giselle Mariano Lessa de ASSIS ◽

...

Keyword(s):

Mating System ◽

Brazilian Amazon ◽

Outcrossing Rate ◽

Fixation Index ◽

Mixed Mating ◽

Mixed Mating System ◽

Arachis Pintoi ◽

Environmental Variations ◽

Increase Productivity ◽

New Cultivars

ABSTRACT The search for alternatives to increase productivity and sustainability of livestock production in the Amazon region without increasing deforestation is challenging. Mixed pastures of grasses with forage peanut (Arachis pintoi) have shown positive economic impacts. However, gaps in the knowledge of the reproductive biology of A. pintoi have limited the development of new cultivars adapted to the environmental variations in the Brazilian Amazon. Pasture consortiums of Brachiaria humidicola with forage peanuts (cv. Mandobi) resulted in a 42% increase in weight gain productivity. New cultivars better adapted to the Amazon climate should bring even greater gains. We evaluated the mating system in twenty A. pintoi accessions, and approximately 40 offspring per accession genotyped with eight microsatellites (or markers). The parameters of genetic diversity and inbreeding, the outcrossing rate and coancestry were calculated. The observed heterozygosity was significantly higher and the fixation index was significantly lower in adults compared with the offspring. The crossing rate was variable among genotypes (2 to 80%), and the mean outcrossing rate was 36%. These results indicate that pollinator presence in pastures can influence gene flow in A. pintoi more than expected. Arachis pintoi presented a mixed mating system with a predominance of selfing, and families presented inbreeding and different levels of relatedness. New strategies of genotype conservation are needed to avoid pollinator-mediated crossing between accessions.

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Genetic Mapping and Nucleotide Diversity of Two Powdery Mildew Resistance Loci in Melon (Cucumis melo)

Phytopathology ◽

10.1094/phyto-03-20-0078-r ◽

2020 ◽

Vol 110 (12) ◽

pp. 1970-1979

Author(s):

Cui Haonan ◽

Ding Zhuo ◽

Fan Chao ◽

Zhu Zicheng ◽

Zhang Hao ◽

...

Keyword(s):

Powdery Mildew ◽

Cucumis Melo ◽

Nucleotide Diversity ◽

Bulked Segregant Analysis ◽

Durable Resistance ◽

Recessive Gene ◽

Segregation Ratio ◽

Epistatic Effect ◽

Fixation Index ◽

Mendelian Segregation

Powdery mildew (PM) significantly and negatively affects the yield and quality of melon (Cucumis melo) worldwide. Race 2F is the predominant physiological race of the pathogen Podosphaera xanthii in many regions. We used accessions PMR 6 (P1; resistant to PM) and M1-7 (P2; susceptible to PM) to analyze the inheritance of resistance to PM (race 2F). The ratio between resistant and susceptible individuals fits a Mendelian segregation ratio of 13:3 in a total of 256 F2 individuals and 1:1 in BC1P2. The resistance to PM in PMR 6 was governed by two genes: a dominant (AA) gene with an epistatic effect and a recessive gene (bb). Only individuals with aaBB or aaBb genotypes were susceptible to PM. Two PM resistance loci, Pm2.1 and pm12.1, were mapped on chromosomes 2 and 12 by bulked segregant analysis and secondary mapping by quantitative trait loci analysis with 18 markers. A new marker-assisted selection system to identify melon genotypes resistant or susceptible to PM was developed and tested in 93 melon accessions. Nucleotide diversity (π) and fixation index (Fst) for the two PM resistance loci were estimated using resequencing data of 336 melons from three groups: C. melo subsp. agrestis, Cucumis melo subsp. melo, and the intermediate type. The lowest π was observed in C. melo ssp. agrestis, and the highest Fst value was between C. melo ssp. agrestis and C. melo ssp. melo. The findings provide a promising tool that can be used to accelerate breeding for durable resistance to PM.

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Intrapopulation fixation index dynamics in finite populations with variable outcrossing rates

Scientia Agricola ◽

10.1590/s0103-90162003000200015 ◽

2003 ◽

Vol 60 (2) ◽

pp. 305-313 ◽

Cited By ~ 4

Author(s):

Alexandre Siqueira Guedes Coelho ◽

Roland Vencovsky

Keyword(s):

Natural Populations ◽

Finite Size ◽

Simulated Data ◽

Outcrossing Rate ◽

Fixation Index ◽

Data Sets ◽

Mean Values ◽

Outcrossing Rates ◽

Size Condition ◽

Simulated Data Sets

The intrapopulation fixation index ( f ) is inversely related to the outcrossing rate (t). Results obtained from data on molecular markers of natural populations have shown that these values are highly variable, even when measured in the same group of individuals. It is thus suggested that factors besides those described in Wright's genetic equilibrium must be operating. Using simulated data sets this study shows that the finite size condition of a population is sufficient to spread the estimated f values along a range at equilibrium, as opposed to keeping them at the theoretical equilibrium point. The variation in outcrossing rates can amplify this range considerably. Correlation between estimated f values obtained from different loci in this condition showed to be negatively related to the outcrossing rates, and positively related to the variance of these rates along generations. The finite size of populations associated to small fluctuations in t mean values over time may explain the usually reported high variation among estimated f values of different loci.

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The influence of jack pine tree and tissue age on the establishment of infection by the jack pine dwarf mistletoe, Arceuthobium americanum

Canadian Journal of Botany ◽

10.1139/b01-027 ◽

2001 ◽

Vol 79 (5) ◽

pp. 521-527

Author(s):

D E Robinson ◽

D Punter

Keyword(s):

Seed Germination ◽

Pinus Banksiana ◽

Jack Pine ◽

Tree Age ◽

Insect Damage ◽

Seed Removal ◽

Dwarf Mistletoe ◽

Susceptibility To Infection ◽

Pine Tree ◽

Arceuthobium Americanum

The purpose of this study was to test the hypothesis that infection of jack pine (Pinus banksiana Lamb.) by jack pine dwarf mistletoe (Arceuthobium americanum Nutt. ex Engelm.) increases with increasing tree age and decreases with increasing tissue age. One-, 2-, and 3-year-old tissues of 3-, 5-, and 7- year-old jack pines and 1-, 4- and 8-year-old tissues of 12-, 17-, and 22-year-old jack pines in Belair Provincial Forest were inoculated with seed of A. americanum in September of 1992 (year 1) and 1993 (year 2). Overwinter and postwinter seed removal, fungal and insect damage, and infection success were monitored from the time of inoculation to harvesting of inoculated branches. In years 1 and 2, overwinter seed displacement was 12.2 and 30.6%, while postwinter loss was 28.8 and 22.2%, respectively. Seed germination ranged from 14.3 to 38.1% and from 3.1 to 17.5%, respectively, in years 1 and 2. Infection success varied from 2.0 to 35.0% (year 1) and from 0.0 to 13.0% (year 2). Lower mean daily temperatures in January and February (p < 0.001) were hypothesized to have killed more seeds and thereby reduced infection success in year 2. Infection success did not increase with increasing tree age (year 1: p = 0.188; year 2: p = 0.807) in either year of the study. Infection success increased with increasing tissue age in year 1 (p < 0.001) but not in year 2 (p = 0.358). We rejected the hypotheses that susceptibility to infection by A. americanum increases with increasing tree age or decreases with increasing tissue age of jack pine. Infection success appears to be primarily dependent upon seed displacement caused by wind, snow, or rain.Key words: jack pine, dwarf mistletoe, infectivity, juvenile resistance, seed displacement.

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Effets à moyen terme de la fertilisation par urée ou par potassium sur Pinusbanksiana L. et le comportement de ses insectes dévastateurs: tel que Neodiprionswainei (Hymenoptera, Tenthredinidae) et Toumeyellanumismaticum (Homoptera, Coccidae)

Canadian Journal of Forest Research ◽

10.1139/x75-032 ◽

1975 ◽

Vol 5 (2) ◽

pp. 236-244 ◽

Cited By ~ 6

Author(s):

W. A. Smirnoff ◽

J. Valéro

Keyword(s):

Osmotic Pressure ◽

Jack Pine ◽

Glutamic Oxaloacetic Transaminase ◽

Urea Nitrogen ◽

Natural Stand ◽

Glutamic Dehydrogenase ◽

Unfertilized Plot ◽

Urea Fertilization ◽

Low Dosage

The effect of fertilization on the physiology of jack pine (Pinusbanksiana Lamb.) in a natural stand and on two important foliage pests, Neodiprionswainei Middleton and Toumeyellanumismaticum Pettit and McDaniel, was studied.It was established in 1973 that fertilization with 400 kg of urea per hectare (1 ha = 1 × 104 m2) in 1969 and in 1970 was still influencing the level of chloride, the osmotic pressure and the activity of two enzymes, glutamic–oxaloacetic transaminase (GOT) and glutamic dehydrogenase (GLDH) contained in the foliage. In June 1974 in current and previous years' growth, the amount of chloride had decreased, respectively, to 81 and 50 p.p.m. (mg/kg) in fertilized trees, and the osmotic pressure increased by 37 and 49 m[Formula: see text]smol/kg. The activity of GOT and GLDH in the foliage of fertilized trees was 41 and 14 mU/g, respectively, compared with 163 and 21 mU/g, respectively, in the foliage of unfertilized trees.It was found 3 years after fertilization that the mortality of N. swainei larvae was 50% higher and the damage they caused was 42% less in fertilized trees. Also, it was observed that urea fertilization, even at low dosage, favoured T. numismaticum, this infestation increasing 2,7 and 9 times in plots fertilized with 100, 200 and 400 kg of urea nitrogen per hectare.The studies revealed, however, that fertilization with potassium may reduce T. numismaticum. The infestation in the fertilized plot showed a reduction from 42 to 21%, and in the unfertilized plot there was an increase from 38 to 80%.

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Some toxic effects of fenitrothion on seed germination and early seedling growth of jack pine, spruce, and birches

Canadian Journal of Forest Research ◽

10.1139/x78-038 ◽

1978 ◽

Vol 8 (2) ◽

pp. 243-246 ◽

Cited By ~ 2

Author(s):

Pearl Weinberger ◽

L. Pomber ◽

R. Prasad

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Tree Species ◽

Boreal Forests ◽

Jack Pine ◽

White Birch ◽

Early Seedling Growth ◽

Percent Germination ◽

Early Seedling ◽

Tree Seeds

The seeds of four tree species (two conifers and two angiosperms) indigenous to the spruce boreal forests of Canada were exposed to 10 ppm (field concentration) and 1000 ppm fenitrothion during stratification and (or) early seedling growth. Pinusbanksiana Lamb. (jack pine) seeds exposed to 1000 ppm fenitrothion germinated more rapidly at first (0–10 days) but later were indistinguishable from untreated or 10 ppm fenitrothion treated seeds. The speed and percent germination of Piceaglauca (Moench) Voss (white spruce) seeds were unaffected by either fenitrothion treatment. After 5 months growth the conifer seedlings derived from fenitrothion treated seeds were comparable to untreated seedlings. The (angiosperm tree) seeds of Betulaalleghaniensis Britton and Betulapaperifera Marsh, (yellow and white birch) showed reduced germination following exposure to 10 ppm fenitrothion and marked toxicological damage when exposed to 1000 ppm fenitrothion.

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Twitter Usage Using Common Reference to Tinnitus

American Journal of Audiology ◽

10.1044/2020_aja-19-00055 ◽

2020 ◽

Vol 29 (2) ◽

pp. 206-217

Author(s):

Jianyuan Ni ◽

Monica L. Bellon-Harn ◽

Jiang Zhang ◽

Yueqing Li ◽

Vinaya Manchaiah

Keyword(s):

Nonprofit Organizations ◽

Temporal Trends ◽

Temporal Analysis ◽

Cross Sectional ◽

For Profit ◽

Common Reference ◽

Personal Experiences ◽

Twitter Users ◽

Sectional Analysis ◽

Share Information

Objective The objective of the study was to examine specific patterns of Twitter usage using common reference to tinnitus. Method The study used cross-sectional analysis of data generated from Twitter data. Twitter content, language, reach, users, accounts, temporal trends, and social networks were examined. Results Around 70,000 tweets were identified and analyzed from May to October 2018. Of the 100 most active Twitter accounts, organizations owned 52%, individuals owned 44%, and 4% of the accounts were unknown. Commercial/for-profit and nonprofit organizations were the most common organization account owners (i.e., 26% and 16%, respectively). Seven unique tweets were identified with a reach of over 400 Twitter users. The greatest reach exceeded 2,000 users. Temporal analysis identified retweet outliers (> 200 retweets per hour) that corresponded to a widely publicized event involving the response of a Twitter user to another user's joke. Content analysis indicated that Twitter is a platform that primarily functions to advocate, share personal experiences, or share information about management of tinnitus rather than to provide social support and build relationships. Conclusions Twitter accounts owned by organizations outnumbered individual accounts, and commercial/for-profit user accounts were the most frequently active organization account type. Analyses of social media use can be helpful in discovering issues of interest to the tinnitus community as well as determining which users and organizations are dominating social network conversations.

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