scholarly journals Rooting of Wild Blueberry (Vaccinium spp.) Cuttings From the Peruvian Northeast

2021 ◽  
Vol 74 ◽  
Author(s):  
José Jesús Tejada-Alvarado ◽  
Jegnes Benjamín Meléndez-Mori ◽  
Nuri Carito Vilca-Valqui ◽  
Eyner Huaman-Huaman ◽  
Manuel Oliva
Keyword(s):  
Butyric Acid ◽  
Natural Populations ◽  
The Other ◽  
Mother Plant ◽  
Northern Peru ◽  
Wild Accessions ◽  
Wild Blueberry

Abstract The objective of this study was to evaluate the effect of indole-3-butyric acid (IBA) on the rooting of five wild accessions of blueberry (HCHA-262, HCHA-271, HCHA-283, HCHA-286, and HCHA-290) obtained from natural populations in the province of Chachapoyas (northern Peru). Buds were collected from the middle third of the plant and treated with IBA at concentrations of 0, 1,000, 2,000, and 3,000 mg L −1 . The results indicated that of the IBA doses, the 2,000-mg L −1 dose achieved the best effects on the rooting percentage and the lengths and numbers of roots and shoots of each accession studied. Accessions HCHA-262 and HCHA-283 showed greater regeneration of new seedlings than the other accessions after 45 days. The rhizogenic capacity of the cuttings varied because of the influences of both the IBA concentration and the genotype of the mother plant.

scholarly journals Sex Differentiation in Amphibians: Effect of Temperature and Its Influence on Sex Reversal

2021 ◽  
pp. 1-11
Author(s):  
Adrián Ruiz-García ◽  
Álvaro S. Roco ◽  
Mónica Bullejos
Keyword(s):  
Sexual Differentiation ◽  
Sex Differentiation ◽  
Environmental Contaminants ◽  
Natural Populations ◽  
Sex Reversal ◽  
The Other ◽  
Effect Of Temperature ◽  
Amphibian Species ◽  
Expected Increase

The role of environmental factors in sexual differentiation in amphibians is not new. The effect of hormones or hormone-like compounds is widely demonstrated. However, the effect of temperature has traditionally been regarded as something anecdotal that occurs in extreme situations and not as a factor to be considered. The data currently available reveal a different situation. Sexual differentiation in some amphibian species can be altered even by small changes in temperature. On the other hand, although not proven, it is possible that temperature is related to the appearance of sex-reversed individuals in natural populations under conditions unrelated to environmental contaminants. According to this, temperature, through sex reversal (phenotypic sex opposed to genetic sex), could play an important role in the turnover of sex-determining genes and in the maintenance of homomorphic sex chromosomes in this group. Accordingly, and given the expected increase in global temperatures, growth and sexual differentiation in amphibians could easily be affected, altering the sex ratio in natural populations and posing major conservation challenges for a group in worldwide decline. It is therefore particularly urgent to understand the mechanism by which temperature affects sexual differentiation in amphibians.

Comparative gene genealogical analyses of strains of serotype AD identify recombination in populations of serotypes A and D in the human pathogenic yeast Cryptococcus neoformans

Microbiology ◽  
2003 ◽  
Vol 149 (8) ◽  
pp. 2147-2154 ◽  
Author(s):  
Jianping Xu ◽  
Thomas G. Mitchell
Keyword(s):  
Monoclonal Antibodies ◽  
Cryptococcus Neoformans ◽  
Natural Populations ◽  
The Other ◽  
Pathogenic Yeast ◽  
Gene Genealogy ◽  
Serotype A ◽  
The World ◽  
Significant Divergence ◽  
Allelic Group

Cryptococcus neoformans is a major pathogen of humans throughout the world. Using commercial monoclonal antibodies to capsular epitopes, strains of C. neoformans manifest five serotypes: A, B, C, D and AD. Previous studies demonstrated significant divergence among serotypes A, B, C and D, which are typically haploid. In contrast, most strains of serotype AD are diploid or aneuploid and result from recent hybridization between strains of serotypes A and D. Whether serotypes A, B, C and D represent strictly asexual lineages is not known. Using comparative genealogical analyses of two genes, the authors investigated whether recombination occurred among strains within serotypes A and D. For each of 14 serotype AD strains, a portion (642 bp) of the orotidine monophosphate pyrophosphorylase (URA5) gene was cloned and sequenced. Each of these 14 strains contained two different alleles and sequences for both alleles were obtained. The URA5 gene genealogy was compared to that derived from the laccase (LAC) gene, which was reported recently for the same 14 strains. For both genes, each of the 14 serotype AD strains contained two phylogenetically distinct alleles: one allele was highly similar to those from serotype A strains and the other to alleles from serotype D strains. However, within both the serotype A allelic group and the serotype D allelic group, there was significant incongruence between genealogies derived from URA5 and LAC. The results suggest recombination in natural populations of both serotypes A and D.

NUMERICAL ANALYSIS OF RANDOM DRIFT IN A CLINE

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 497-517
Author(s):  
Thomas Nagylaki ◽  
Bradley Lucier
Keyword(s):  
Natural Populations ◽  
The Other ◽  
Random Genetic Drift ◽  
Gene Frequencies ◽  
Random Drift ◽  
Linear Habitat ◽  
Asymptotic Formulae ◽  
A Chain ◽  
Average Position ◽  
Uniform Population

ABSTRACT The equilibrium state of a diffusion model for random genetic drift in a cline is analyzed numerically. The monoecious organism occupies an unbounded linear habitat with constant, uniform population density. Migration is homogeneouq symmetric and independent of genotype. A single diallelic locus with a step environment is investigated in the absence of dominance and mutation. The flattening of the expected cline due to random drift is very slight in natural populations. The ratio of the variance of either gene frequency to the product of the expected gene frequencies decreases monotonically to a nonzero constant. The correlation between the gene frequencies at two points decreases monotonically to zero as the separation is increased with the average position fixed; the decrease is asymptotically exponential. The correlation decreases monotonically to a positive constant depending on the separation as the average position increasingly deviates from the center of the cline with the separation fixed. The correlation also decreases monotonically to zero if one of the points is fixed and the other is moved outward in the habitat, the ultimate decrease again being exponential. Some asymptotic formulae are derived analytically.—The loss of an allele favored in an environmental pocket is investigated by simulating a chain of demes exchanging migrants, the other assumptions being the same as above. For most natural populations, provided the allele would be maintained in the population deterministically, this process is too slow to have evolutionary importance.

scholarly journals An elusive new species of gymnophthalmid lizard (Cercosaurinae, Selvasaura) from the Andes of northern Peru

2021 ◽  
Vol 5 (2) ◽  
pp. 177-187
Author(s):  
Lourdes Y. Echevarría ◽  
Pablo J. Venegas ◽  
Luis A. García-Ayachi ◽  
Pedro M. Sales Nunes
Keyword(s):  
New Species ◽  
Natural History ◽  
Phylogenetic Analyses ◽  
Morphological Characters ◽  
The Other ◽  
Adult Males ◽  
The Andes ◽  
New States ◽  
Northern Peru ◽  
A New Species

We describe a new species of Selvasaura from the montane forests of the eastern slopes of the Andes in northern Peru, based on external and hemipenial morphological characters and previous phylogenetic analyses. The new species can be differentiated from the other two Selvasaura species in having keeled dorsal scales usually flanked by longitudinal striations, in adults and juveniles; adult males with a yellow vertebral stripe bordered by broad dark brown stripes on each side and a unilobed hemipenis surrounded by the branches of the sulcus spermaticus. The description of the new species contributes information about new states of diagnostic characters of Selvasaura and natural history.

Genes and the Evolutionary Synthesis

1986 ◽  
Author(s):  
Niles Eldredge
Keyword(s):  
Natural Populations ◽  
The Other ◽  
Special Treatment ◽  
Origin Of Species ◽  
Close Analysis ◽  
Isolating Mechanisms ◽  
Historical Effect ◽  
Four Books ◽  
Species Definitions ◽  
Illustrative Material

My intention in this and the following chapter is simply to clarify what a few of the better known architects of the synthesis actually had to say about how the entire spectrum of genes through phyla really fits together. I have chosen books rather than a potpourri of articles from the (possibly) more “technical” scientific literature, for precisely this reason: it is in the books that we find the coherent, integrated statements. And each of the four books singled out for particularly close analysis—Genetics and the Origin of Species (Dobzhansky 1937a); Genetics and the Origin of Species second edition (Dobzhansky 1941); Systematics and the Origin of Species (Mayr 1942); and Tempo and Mode in Evolution (Simpson 1944)—is a truly coherent, though not necessarily smoothly linear, argument. In each, some parts seem more vital to the flow of argument than others, but it is clear to the reader from the outset that each is a complete book and not a disjointed melange of unrelated ideas. Then, too, the contents of each author’s papers are to a great extent reflected in the respective books. It is apparent, for example, that Dobzhansky was publishing a variety of papers in the 1930s (many were in his “Genetics of Natural Populations” series republished in a single volume in 1981 by Lewontin et al.) which he liberally drew upon for illustrative material in Genetics and the Origin of Species. The other sorts of papers Dobzhansky was publishing seem to be byproducts of his thinking and research for the various editions of his book. Examples are his papers on species definitions (1935) and isolating mechanisms (1937b) and his theory of the origin of isolating mechanisms by reinforcement (1940). The choice of the four particular books for special treatment in this volume needs further comment. I have omitted such nonconformist works as Robson and Richards (1936), Willis (1940), and Goldschmidt (1940) precisely because they have been almost universally considered as falling outside the limits of the synthesis. The main historical effect of such books (especially Goldschmidt’s) seems to have been as irritants.

Aptitudes germinatives comparées de graines de Rumex acetosella issues de populations correspondant à des stades distincts d'une succession postculturale

1988 ◽  
Vol 66 (7) ◽  
pp. 1381-1390 ◽  
Author(s):  
J. Escarré ◽  
C. Houssard
Keyword(s):  
Seed Weight ◽  
Plant Biomass ◽  
Germination Rate ◽  
The Other ◽  
Mother Plant ◽  
Old Fields ◽  
Rumex Acetosella ◽  
Significant Difference ◽  
Flowering Rate ◽  
Mother Plants

Germination of Rumex acetosella L. was studied under a variety of experimental conditions to determine whether populations from old fields of different ages (fallow for 6 months to 15 years) differed in seed weight and germination rate and in plant biomass and flowering rate of the resulting plants. Fresh seeds collected from these natural populations showed differences in germination that varied with the date of harvest and the number of years since the field was last cultivated: seeds of the youngest population harvested in July germinated the best and were lighter than those of the other populations. Different fertilizer levels applied during the growth of the mother plants from seeds collected in the original old fields affected the mean weight and the germination rate of the resulting seeds, regardless of the density of cultivation of the mother plant. However, the effect of different fertilizer levels on mean seed weight varied with the origin of each population. Heavy seeds (mean weight > 0.6 mg) of mother plants from the populations of fields abandoned over 2 years ago germinated better than light seeds (mean weight < 0.6 mg). There was no significant difference between heavy and light seeds in terms of percent germination for seeds from mother plants that came from the "youngest" field. These differences in germination rate observed in field-collected seeds were also found in light seeds of the offspring generation: light seeds of the mother plant from the population belonging to the more recently abandoned old field germinated the best. Plants grown from heavy seeds that came from the other populations of older fields had more biomass than those resulting from light seeds. This difference has not been observed between individuals resulting from light and heavy seeds of the youngest population. On the other hand, these individuals had a higher flowering rate than those resulting from the older populations. These results are interpreted in relation to the successional status of the populations: high flowering and early germination rates are suitable characteristics for establishment of plants on bare ground or after a disturbance, whereas heavy seeds with more reserves ensure germination and enough biomass of the resulting plants in density-dependent conditions.

A Paedomorphocline in Eucalyptus. II. Variation in Seedling Morphology in the E. risdonii/E. tenuiramis Complex

1992 ◽  
Vol 40 (6) ◽  
pp. 789 ◽  
Author(s):  
RJE Wiltshire ◽  
BM Potts ◽  
JB Reid
Keyword(s):  
East Coast ◽  
Natural Populations ◽  
The Other ◽  
Ontogenetic Variation ◽  
Seedling Morphology ◽  
Transitional Area ◽  
Juvenile Leaf ◽  
Phenetic Relationships ◽  
The Difference ◽  
The Relationship

Previous studies of phenotypic variation among natural populations in the Eucalyptus risdonii/E. tenuiramis cindicated that the two taxa are linked by a cline in the retention of the juvenile leaf form (paedomorphocline) and that division into the two taxa, E. risdonii and E. tenuiramis, on the basis of these ontogenetic differences obscures the phenetic relationships within and between the taxa. This study attempts to remove the environmental and ontogenetic variation to reveal the genetically based variation by examining seedling morphology. The results suggest that genetic variation between geographically contiguous populations of E. risdonii and E. tenuiramis is relatively small and continuous, and classification into either taxon on the basis of seedling phenotype is not possible for populations in this transitional area. The major dichotomy between phenetic clusters is not between forms that can be assigned to E. risdonii and E. tenuiramis on the basis of ontogenetic differences, but between geographically isolated forms of E. tenuiramis. The ambiguous variation in the adult phenotype is clarified by the marked difference in seedling morphology between the two East Coast populations and the other E. tenuiramis populations which, on present data, appear to be separated by a geographical disjunction. When viewed in terms of the phenetic distance between populations of the two closest species (E. coccifera and E. nitida), the magnitude of the difference between the East Coast E. tenuiramis and the other phenetic groups in the E. risdonii/E. tenuiramis complex is emphasised. The relationship and origin of populations intermediate between E. tenuiramis and E. coccifera are also discussed.

scholarly journals Determining the Rooting Ability of Hardwood Cuttings of Blueberry (Vaccinium corymbosum L.) cv. ‘Bluecrop’ Stored in Refrigerating Conditions

2020 ◽  
Vol 8 (3) ◽  
pp. 81
Author(s):  
Sabri Braha ◽  
Petrit Rama ◽  
Agim Zajmi
Keyword(s):  
Acetic Acid ◽  
Butyric Acid ◽  
Adventitious Roots ◽  
Vaccinium Corymbosum ◽  
Mother Plant ◽  
Winter Period ◽  
Naphthalene Acetic Acid ◽  
Intact Control ◽  
Rooting Ability ◽  
Time Periods

This experiment has been carried out in order to determine the rooting ability of hardwood cuttings of the blueberry cultivar ‘Bluecrop’ collected during the deep dormant winter period in the last part of January. In order to induce the adventitious roots formation, the cuttings were stimulated using Indol Butyric Acid (IBA) and Naphthalene Acetic Acid (NAA) in various concentrations (1500, 3000, 4500 ppm), whilst one row in each box remained intact (control).  The collection of cuttings off the mother plant at the beginning of January enable the nutrients and other matter that help the process of rooting not to move from the base of cutting towards the top and consequently they remain at the base of cutting which results with quite a high rooting percentage (up to 72.5%) compared to the cuttings collected in February with rooting percentage of 67.5% and in March (52%). In both types of substrate, turf and turf-perlite 2:1 and in different time periods when cuttings have been collected, IBA proved to be better in inducing adventitious roots compared to NAA.

An Experiment On Spacing-Out as a Defence Against Predation

Behaviour ◽  
1967 ◽  
Vol 28 (3-4) ◽  
pp. 307-320 ◽  
Author(s):  
D. Franck ◽  
M. Impekoven ◽  
N. Tinbergen
Keyword(s):  
Selection Pressure ◽  
Standard Sample ◽  
Direct Detection ◽  
Natural Populations ◽  
The Other ◽  
Detection Distance ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Scattered Population ◽  
Dependent Mortality

AbstractThe paper is concerned with the tracing of a selection pressure which would account for the fact (believed to be sufficiently well established) that individuals of many well-camouflaged species live further away from other individuals of their species than the distance from which even bird predators are able to detect them. Artificially camouflaged hens' eggs were laid out in plots of different densities. Wild Carrion Crows were attracted to each plot by a standard "sample egg" which, while painted in the same way as the other eggs on the uppermost half, was laid out in a more conspicuous way. In spite of the fact that the Crows spent more time searching in the "scattered" than in the "crowded" plots, the crowded eggs suffered a much higher mortality. It is concluded that even for individuals of a well-camouflaged species it must be of advantage to live further away from others than the Direct Detection Distance of their predators. However, the experiments do not show that a crowded population as a whole suffers higher predation than a scattered population; experiments to test this and other aspects of the problem are in progress. It is argued that the absolute values of the density dependent mortality scores of the experiments cannot be applied to natural populations, because their density will in most cases be determined by other ultimate factors as well.

Early Watertable Farming on the North Coast of Peru

1979 ◽  
Vol 44 (1) ◽  
pp. 138-144 ◽  
Author(s):  
Michael West
Keyword(s):  
The Other ◽  
North Coast ◽  
Intermediate Period ◽  
The North ◽  
Early Intermediate Period ◽  
Northern Peru ◽  
Field Systems ◽  
North Coast Of Peru

An archaeological example of simple watertable farming dating to the beginning of the Early Intermediate period in the Viru Valley, northern Peru, is reported. This technique was deployed by functionally differentiated segments of a single community, one stressing fishing and the other farming. Analyses of pollens indicate that Zea, Leguminosae, and Solonaceae were grown in two separate field systems.

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