GENETIC DIVERGENCE AMONG EASTERN NORTH AMERICAN CONE BEETLES, CONOPHTHORUS (COLEOPTERA: SCOLYTIDAE)

1992 ◽  
Vol 124 (1) ◽  
pp. 189-199 ◽  
Author(s):  
Peter de Groot ◽  
George T. Harvey ◽  
Pat M. Roden
Keyword(s):  
Genetic Distance ◽  
Genetic Divergence ◽  
Null Hypothesis ◽  
Red Pine ◽  
Fixation Index ◽  
Pairwise Comparisons ◽  
White Pine ◽  
Genotype Frequencies ◽  
Electrophoretic Data ◽  
Pine Cones

AbstractGenetic divergence among populations of cone beetles, Conophthorus banksianae McPherson, C. coniperda (Schwarz), and C. resinosae Hopkins, was assessed by isozyme electrophoretic data. All but one of the eight loci examined were polymorphic, and one locus (Pgi) was sex-linked for C. coniperda. Genotype frequencies generally met Hardy-Weinberg expectations, and fixation index (FST) values indicated low-to-moderate genetic differences among conspecific populations. Fixed allele differences were detected at two loci, Pgi and Dia-2, which separated C. resinosae from C. coniperda, and thus confirmed their specific status established previously by morphological, karyological, and other biochemical characters. Electrophoretic data strongly suggested C. coniperda does not attack red pine cones, and C. resinosae does not attack white pine cones. No diagnostic loci were found to separate C. resinosae from C. banksianae. Phenetic clustering and pairwise comparisons of genetic distance coefficients indicated very little genetic divergence between C. resinosae and C. banksianae. These data were interpreted as failing to reject the null hypothesis that C. resinosae and C. banksianae are one species, an interpretation consistent with available taxonomic evidence from ecological, karyological, and other biochemical characters.

GENETIC DIVERGENCE IN BABUL (ACACIA NILOTIKA)

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
SUDHANSHU SHEKHAR ◽  
V.P. DWIVEDI ◽  
N.K. SRIVASTAVA
Keyword(s):  
Genetic Distance ◽  
Genetic Divergence ◽  
Acacia Nilotica ◽  
Hybridization Programme

Genetic divergence of Babul (Acacia nilotica) was assessed using Mahalanobis 0 statistics. They were grouped into eight clusters. Maximum genetic distance was recorded between III & VIII ciusters indicating greater distance between two clusters that showed maximum diversity amount the genotype and helps in hybridization programme.

THE SEED PRODUCTION CAPACITY AND EFFICIENCY OF RED PINE CONES (PINUS RESINOSA AIT.)

1956 ◽  
Vol 34 (1) ◽  
pp. 27-36 ◽  
Author(s):  
L. A. Lyons
Keyword(s):  
Seed Production ◽  
Production Efficiency ◽  
Production Capacity ◽  
Pinus Resinosa ◽  
Proximal Part ◽  
Red Pine ◽  
First Year ◽  
Tree Crown ◽  
Second Year ◽  
Pine Cones

The seed capacity of red pine cones varies from about 30 to over 110, depending on the size of the cone and its position in the tree crown, and is determined by the number of ovules that are structurally complete at the time of pollination. These ovules occur in a central "productive" region and constitute less than one-half of the total. The remaining ovules, most: of which are in the proximal part of the cone, never become structurally perfect, and do not contribute to seed production. Abortion of ovules in the productive region usually reduces seed production efficiency to 50–60%, and is accompanied mainly by withering of the nucellus in the first year and failure to produce archegonia early in the second year. The extent of ovule abortion during the first year varies indirectly with cone size, seed capacity, and height in tree.

Current understanding of white and red pine physiology

1994 ◽  
Vol 70 (4) ◽  
pp. 420-426 ◽  
Author(s):  
Suzanne Wetzel ◽  
Darwin Burgess
Keyword(s):  
Economic Value ◽  
Measurement Data ◽  
Field Studies ◽  
Forest Growth ◽  
Red Pine ◽  
Tree Level ◽  
White Pine ◽  
Growth Measurement ◽  
Pine Tree ◽  
Physiological Processes

For significant and predictable improvements in productivity of red and white pine forests, an increased understanding of the physiological processes in these species is essential. Relatively little physiological research has focused on these two species over the last two decades. However, with renewed interest in these species now for their high social, environmental and economic value this situation is changing. This paper describes past efforts at understanding red and white pine physiology, as well as discussing recent achievements. In addition, new results obtained by the authors through the use of Biotronic growth units are described in more detail to emphasize the high adaptability of white pine seedlings in response to nutrient stress through changes in carbon distribution, nutrient uptake and utilization.The ultimate practical output of much forestry research is often models predicting tree and forest growth. However, models which are based solely on empirical growth measurement data will not provide the understanding that is necessary for sustainable management; thus, increased research on physiological processes will continue to be required in future. Long-term detailed field studies that consider environmental and silvicultural influences at the organ and whole tree level are required to ensure that future models have high explanatory value. Key words: white pine, red pine, tree physiology, photosynthesis, seedling nutrition, silviculture

scholarly journals Population Structure of Phytophthora cinnamomi in South Africa

1997 ◽  
Vol 87 (8) ◽  
pp. 822-827 ◽  
Author(s):  
C. Linde ◽  
A. Drenth ◽  
G. H. J. Kemp ◽  
M. J. Wingfield ◽  
S. L. von Broembsen
Keyword(s):  
South Africa ◽  
Genetic Distance ◽  
South African ◽  
Mating Type ◽  
Phytophthora Cinnamomi ◽  
Regional Distribution ◽  
Specific Pattern ◽  
Fixation Index ◽  
The South ◽  
Hardy Weinberg Equilibrium

Phytophthora cinnamomi isolates collected from 1977 to 1986 and 1991 to 1993 in two regions in South Africa were analyzed using isozymes. A total of 135 isolates was analyzed for 14 enzymes representing 20 putative loci, of which four were polymorphic. This led to the identification of nine different multilocus isozyme genotypes. Both mating types of P. cinnamomi occurred commonly in the Cape region, whereas, predominantly, the A2 mating type occurred in the Mpumalanga region of South Africa. A2 mating type isolates could be resolved into seven multilocus isozyme genotypes, compared with only two multilocus isozyme genotypes for the A1 mating type isolates. Low levels of gene (0.115) and genotypic (2.4%) diversity and a low number of alleles per locus (1.43) were observed for the South African P. cinnamomi population. The genetic distance between the Cape and Mpumalanga P. cinnamomi populations was relatively low (Dm = 0.165), and no specific pattern in regional distribution of multilocus isozyme genotypes could be observed. The genetic distance between the “old” (isolated between 1977 and 1986) and “new” (isolated between 1991 and 1993) P. cinnamomi populations from the Cape was low (Dm = 0.164), indicating a stable population over time. Three of the nine multilocus isozyme genotypes were specific to the “old” population, and only one multilocus isozyme genotype was specific to the “new” population. Significant differences in allele frequencies, a high genetic distance (Dm = 0.581) between the Cape A1 and A2 mating type isolates, significant deviations from Hardy-Weinberg equilibrium, a low overall level of heterozygosity, and a high fixation index (0.71) all indicate that sexual reproduction occurs rarely, if at all, in the South African P. cinnamomi population.

USE OF THE RELATIVE TURGIDITY TECHNIQUE FOR MEASUREMENT OF WATER STRESSES IN GYMNOSPERM LEAVES

1965 ◽  
Vol 43 (2) ◽  
pp. 305-316 ◽  
Author(s):  
J. J. Clausen ◽  
T. T. Kozlowski
Keyword(s):  
Abies Balsamea ◽  
Pinus Resinosa ◽  
Tsuga Canadensis ◽  
Red Pine ◽  
Eastern Hemlock ◽  
Balsam Fir ◽  
White Pine ◽  
Sampling Variation

Adaptations of Weatherley's relative turgidity technique (Weatherley 1950), fitting it for use with red pine (Pinus resinosa Ait.), white pine (P. strobus L.), balsam fir (Abies balsamea (L.) Mill.), and eastern hemlock (Tsuga canadensis (L.) Carr.) are described. Results of preliminary investigations of sampling variation between trees, whorls, and needle ages in red pine are presented.

scholarly journals Genetic divergence correlates with the contemporary landscape in populations of Slimy Salamander (Plethodon glutinosus) species complex across the lower Piedmont and Coastal Plain of the southeastern United States

2018 ◽  
Vol 96 (11) ◽  
pp. 1244-1254 ◽  
Author(s):  
Walter H. Smith ◽  
Jessica A. Wooten ◽  
Carlos D. Camp ◽  
Dirk J. Stevenson ◽  
John B. Jensen ◽  
...  
Keyword(s):  
South Carolina ◽  
Genetic Distance ◽  
Principal Components ◽  
Coastal Plain ◽  
Genetic Divergence ◽  
Species Complex ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Plethodon Glutinosus ◽  
Isolation By Environment

A primary goal of landscape genetics is to elucidate factors associated with genetic structure among populations. Among the important patterns identified have been isolation by distance (IBD), isolation by barrier (IBB), and isolation by environment (IBE). We tested hypotheses relating each of these possible patterns to genetic divergence in the Slimy Salamander (Plethodon glutinosus (Green, 1818)) species complex across the lower Piedmont and Coastal Plain of Georgia, USA, and adjacent areas of South Carolina, USA. We sequenced 2148 total bp, including three regions of the mitochondrial genome and a nuclear intron, and related genetic distance to GIS-derived surrogate variables representing possible IBD (geographic distance), IBE (principal components of 19 climate variables, watershed, and normalized difference vegetation index (NDVI)), and IBB (streams of fourth order and higher). Multiple matrix regression with randomization analysis indicated significant relationships between genetic distance and two principal components of climate, as well as NDVI. These results support roles for environment (IBE) in helping to drive genetic divergence in this group of salamanders. The absence of a significant influence of IBD and IBB was surprising. It is possible that the signal effects of geographic distance and barriers on genetic divergence may have been erased by more recent responses to the environment.

Heterosis in relation to genetic divergence in short duration maize (Zea mays L.)

2021 ◽  
pp. 137-142
Author(s):  
Bal Krishna ◽  
Birender Singh ◽  
Shyam Sundar Mandal ◽  
Rashmi Kumari ◽  
Tushar Ranjan
Keyword(s):  
Genetic Distance ◽  
Genetic Divergence ◽  
Zea Mays L ◽  
Correlation Coefficients ◽  
Negative Association ◽  
Coefficient Of Determination ◽  
Maize Hybrids ◽  
Single Cross ◽  
Per Se ◽  
Linear Regressions

Thirteen lines and three testers were used to produce 39 single cross maize hybrids by line Ítester mating design. The genetic divergence among thirteen lines and three tester of maize were estimated by using Mahalanobis D2 statistic for twelve characters. The genotypes were grouped into five clusters. Cluster I comprised 12 parental genotypes (L1, L2, L3, L4, L5; L6, L7, L8, L9, L11; L12, L13), while Cluster II (T3), III (T1), IV (L10) and V (T2) were mono-genotypic, suggesting more variability in genetic makeup of the genotypes included in these clusters. The correlation coefficients and linear regressions were used to know the effects of parental genetic distance in determining heterosis and per se performance of the hybrids. Parental genetic distance exhibited significant negative association and significant linear regression along with very low coefficient of determination with better parent heterosis (BPH) and non-significant with per se performance of the hybrids. The present investigation, therefore, the parental genetic distance has significant role in determining heterosis and hybrid performance in kharif maize.

scholarly journals Some Relationships Between Silvicultural Treatments and Symmetry of Stem Growth in a Red Pine Stand

1998 ◽  
Vol 15 (2) ◽  
pp. 90-93 ◽  
Author(s):  
Bruce C. Larson ◽  
W. Keith Moser ◽  
Vijay K. Mishra
Keyword(s):  
Growth Patterns ◽  
Red Pine ◽  
Mixed Stand ◽  
Stand Age ◽  
Pure Stand ◽  
White Pine ◽  
Silvicultural Treatments ◽  
Growth Increments ◽  
Crown Shape ◽  
Asymmetric Growth

Abstract Variations in spacing and the distribution of removed trees have been assumed to affect the pattern of growth on tree boles. Changing crown shapes were believed to affect the symmetry of the stems. This study examined the change of growing space resulting from differential species' growth in a mixed stand. A red pine (Pinus resinosa Ait.) plantation in southern New Hampshire was planted at 2 × 2 m spacing in 1917. At one end of the stand every second row was planted with white pine (Pinus strobus L.), whereas the other end of the stand was pure red pine. In the mixed portion of the stand, the red pine outgrew the white pine, overtopping and often killing it. The mixed stand was thinned in the 1970s and the pure stand in the 1980s for a variety of products which opened more crown room for some of the trees. We compared growth increments along perpendicular axes to determine if asymmetry was consistent at different bole heights. The study did not show asymmetric boles at age 50 and did not have asymmetric growth patterns attributable to the earlier history up to stand age 70. When current crown shape was compared to current growth there was no relationship between asymmetric crowns and asymmetric growth. Provided the asymmetry is not maintained throughout the entire rotation, silvicultural treatments which greatly affect the stand spatial pattern may not have a lasting effect on the symmetry of the boles. North. J. Appl. For. 15(2):90-93.

Critical period of interspecific competition for four northern conifers: 10-year growth response and associated vegetation dynamics

2006 ◽  
Vol 36 (10) ◽  
pp. 2474-2485 ◽  
Author(s):  
Robert G Wagner ◽  
Andrew P Robinson
Keyword(s):  
Interspecific Competition ◽  
Critical Period ◽  
Black Spruce ◽  
Jack Pine ◽  
Red Pine ◽  
Growth Responses ◽  
White Pine ◽  
Conifer Species ◽  
Stand Volume ◽  
Vegetation Control

The influence of the timing and duration of interspecific competition on planted jack pine (Pinus banksiana Lamb.), red pine (Pinus resinosa Ait.), eastern white pine (Pinus strobus L.), and black spruce (Picea mariana (Mill.) BSP) was assessed using 10-year growth responses in a northern Ontario experiment. Stand volume was 117%, 208%, 224%, and 343% higher for jack pine, red pine, white pine, and black spruce, respectively, with 5 years of vegetation control than with no vegetation control. Stand volume increased linearly with number of years of vegetation control, and the slope of the relationship varied among conifer species. Change-point regression analysis was used to derive segmented weed-free and weed-infested curves, and to simultaneously estimate key critical-period parameters. Weed-free and weed-infested curves in the 10th year were similar to those derived in year 5, indicating that the patterns established during the first few years after planting were relatively robust for the first decade. The critical-period was 2 and 3 years after planting for jack pine and red pine, respectively, and occupied most of the 5-year period for white pine and black spruce. Principal components analysis of the vegetation community indicated that repeated herbicide applications caused differential shifts in the relative abundance of shrub, fern, and moss species through the 10th year. Species richness, however, was not substantially different between the untreated control and the most intensive treatments. Difference modeling was used to quantify how annual volume increment during the first decade varied with time, conifer species, cover of woody and herbaceous vegetation, and stage of development.

Surface burning in a mature stand of Pinus resinosa and Pinus strobus in Michigan: effects on understory vegetation

2001 ◽  
Vol 10 (1) ◽  
pp. 91 ◽  
Author(s):  
David D. Neumann ◽  
Donald I. Dickmann
Keyword(s):  
Late Summer ◽  
Pinus Resinosa ◽  
Red Pine ◽  
Phytolacca Americana ◽  
Vegetative Cover ◽  
White Pine ◽  
Periodic Surface ◽  
Surface Fires ◽  
Growing Seasons ◽  
Surface Burning

Beginning in 1991, periodic surface fires (frontal fire intensities <200 kW m–1) were introduced into a mixed red pine (Pinus resinosa Ait.) and white pine (P. strobus L.) plantation (dbh 16–60 cm). Replicated plots of 0.4–0.5 ha were either burned three times at biennial intervals (early May of 1991, 1993, and 1995), burned once (early May 1991), or not burned. Measurements were conducted during the 1994 and 1995 growing seasons. The pine overstory was largely unaffected by the fires. The understory on unburned plots contained 16 111 large seedlings (>1 m, ≤ 1.9 cm dbh) and 3944 saplings (2.0–5.9 cm dbh) per ha, consisting of 23 woody angiosperm taxa. Plots burned once contained 60% of the large seedlings, 7% of the saplings, and 6 fewer taxa than unburned plots. No large seedlings and few saplings were found in plots burned biennially. Cover of low (<1 m) woody and herbaceous vegetation in plots burned once or three times was twice that of unburned plots, even in the growing season immediately following the May 1995 re-burn. Recovery of low vegetative cover in the re-burned plots was rapid, exceeding that in once-burned or unburned plots by late summer following the burn. Species richness of low vegetation was 20–25% higher in burned than unburned plots, except in the year immediately following reburning. Taxa dominating this site following burning were Sassafras albidum (Nutt.) Nees, Rubus spp., Phytolacca americana L., and Dryopteris spinulosa (O.F. MÜll.) Watt. Restoration of low-intensity surface fires to ecosystems dominated by mature red pine or white pine is feasible, but major changes in understory structure and composition will occur.

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