Contrasting Success of Natural Hybridization in Two Eucalyptus Species Pairs

1980 ◽  
Vol 28 (2) ◽  
pp. 167 ◽  
Author(s):  
DW Drake
Keyword(s):  
Principal Component ◽  
Flowering Phenology ◽  
Natural Hybridization ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Eucalyptus Species ◽  
Major Barrier ◽  
Species Pairs ◽  
Plant Hybridization ◽  
Hybrid Number

A morphological study with univariate and principal component analyses of mature tree and open-pollinated seedling populations shows that natural hybridization is occurring between Eucalyptus melanophloia and E. crebra, and E. populnea and E. crebra (subgenus Symphyomyrtus, section Adnataria). The level of successful hybridization in these two systems, where fundamental genetic (reproductive) and ecological (habitat and spatial) barriers are absent, is examined. Within the ecotone, hybrids between E. melanophloia and E. crebra are about one-fifth as frequent as those between E. populnea and E. crebra. Analyses of the phenotype/genotype compositions of the hybrid populations, the patterns of segregation, and outcrossing frequencies between the species pairs indicate the level of development of the hybrid populations. All E. melanophloia × E. crebra hybrids appear to be F1 hybrids. In contrast, the E.populnea x E. crebra hybrid population attains a much higher level of development in terms of both hybrid number and genotypic complexity. Flowering phenology is a major barrier to E. melanophloia × E. crebra hybrid formation compared with the other hybrids, although it is considered an incomplete barrier and alone may not explain the diversity of hybrid success which occurs.A theory of plant hybridization which incorporates the concept of hybridization success is presented and discussed in relation to the two hybridizing systems, as a basis for further investigating the mechanisms involved.

Progeny Trials in an Introgressive Hybrid Population of Anigozanthos Labill. (Haemodoraceae)

1978 ◽  
Vol 26 (3) ◽  
pp. 309 ◽  
Author(s):  
SD Hopper
Keyword(s):  
Floral Morphology ◽  
Natural Hybridization ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Evolutionary Significance ◽  
Gene Exchange ◽  
Present Evidence ◽  
Close Proximity ◽  
Two Generations ◽  
Open Question

The floral morphology and pollen fertility of progeny from open-pollinated plants in a hybrid population of A. manglesii and A. humilis were measured to investigate patterns of gene exchange occurring between hybrid and parental individuals. Introgression occurs where the two species and F1 hybrids grow in close proximity in the population but the possibility of more backcrossing to A. manglesii than to A. humilis remains an open question on present evidence. The morphological effects of hybridization became cryptic in some cases within one and in most cases within two generations of backcrossing. The possible evolutionary significance of natural hybridization between A. manglesii and A. humilis is discussed in the light of these results.

EVALUATION OF HYBRID SPRING WHEAT POPULATIONS

2018 ◽  
pp. 37-39
Author(s):  
O. V. Gladysheva ◽  
Т. А. Barkovskaya
Keyword(s):  
Correlation Coefficient ◽  
Spring Wheat ◽  
Dominant Role ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Selection Of

This article presents the results of a study of hybrid spring wheat populations. Revealed different patterns of inheritance of important traits in F1 hybrids, which is caused by hereditary features of the original forms and circumstances. Analysis of hybrid populations showed that the dominant role in the formation of 1000 grains mass belongs to productivity and weight of grain with an ear, correlation coefficient r = 0.90 and amounted to r = 0.73, respectively. Found that the hybrid population in F4-5, created on the basis of grades Moscow 35, Esther, Agatha, Rome, Saratovskaya 29 (Russia), Ostinka (Ukraine) are a valuable material for selection of highly productive genotypes for future use breeding process. 

Genetic Evaluation and Bi-plot Analysis in Okra Hybrids for Yield, Quality Components and YVMV Resistance

2018 ◽  
Vol 5 (04) ◽  
Author(s):  
SS SOLANKEY ◽  
ANIL K SINGH
Keyword(s):  
Genetic Divergence ◽  
Principal Component ◽  
F1 Hybrids ◽  
Genetic Advance ◽  
Economic Traits ◽  
Cross Combination ◽  
Plot Analysis ◽  
Eigen Value ◽  
Coefficient Of Variability ◽  
Yield Quality

Fifty one okra F1 hybrids (using 17 lines as female and 3 testers as male parent) were evaluated in RCBD design during two different consecutive seasons (summer and rainy). Phenotypic coefficient of variability (PCV) was higher than genotypic coefficient of variability (GCV) for all studied character exhibiting environmental effects on the expression of characters. Heritability (h2b) along with genetic advance per cent of mean was found highest for character YVMV (86.95% and 150.61%). All the 51 okra hybrids were grouped into 4 distinct clusters in which Cluster II was the largest cluster having 28 F1s (54.90% of total F1s) followed by Cluster I with 14 F1s (27.45% of total F1s). Out of the major 6 PCs, 4 principal components (PC1, PC2, PC3 and PC4) accounted with proportionate values of 22.61, 17.22, 11.87 and 10.63%, respectively and contributed 62.33 % of the cumulative variation having Eigen value more than one. Moreover, based on PCs and genetic divergence in Cluster I and Cluster IV for plant height, YVMV and number of fruit per plant is important to identify the best cross combination (Arka Abhay × Arka Anamika) in okra. Therefore, the best cross combinations for improvement in various economic traits can be recommended on the basis of genetic divergence and principal component analysis in okra.

Natural hybridization between an outcrossing and a selfingPhlox (Polemoniaceae): The maternal species of F1 hybrids

1999 ◽  
Vol 218 (1-2) ◽  
pp. 153-158 ◽  
Author(s):  
Carolyn J. Ferguson ◽  
Donald A. Levin ◽  
Robert K. Jansen
Keyword(s):  
Natural Hybridization ◽  
F1 Hybrids

scholarly journals Reciprocal F1 hybrids of two inbred mouse strains reveal parent-of-origin and perinatal diet effects on behavior and expression

2018 ◽  
Author(s):  
Daniel Oreperk ◽  
Sarah A Schoenrock ◽  
Rachel McMullan ◽  
Robin Ervin ◽  
Joseph Farrington ◽  
...  
Keyword(s):  
Complex Traits ◽  
Detection System ◽  
Inbred Mouse ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Psychiatric Disease ◽  
Mouse Strains ◽  
Imprinted Genes ◽  
F1 Hybrid ◽  
Parent Of Origin

ABSTRACTParent-of-origin effects (POEs) in mammals typically arise from maternal effects or from imprinting. Mutations in imprinted genes have been associated with psychiatric disorders, as well as with changes in a handful of animal behaviors. Nonetheless, POEs on complex traits such as behavior remain largely uncharacterized. Furthermore, although perinatal environmental exposures, such as nutrient deficiency, are known to modify both behavior and epigenetic effects generally, the architecture of environment-by-POE is almost completely unexplored. To study POE and environment-by-POE, we employ a relatively neglected but maximally powerful POE-detection system: a reciprocal F1 hybrid population. We exposed female NOD/ShiLtJxC57Bl/6J and C57Bl/6JxNOD/ShiLtJ mice, in utero, to one of four different diets, then after weaning recorded their whole-brain gene expression, as well as a set of behaviors that model psychiatric disease. Microarray expression data revealed an imprinting-enriched set of over a dozen genes subject to POE; the POE on the most significantly affected gene, Carmil1 (a.k.a. Lrrc16a), was validated using qPCR in the same and in a new set of mice. Several behaviors, especially locomotor behaviors, also showed POE. Interestingly, Bayesian mediation analysis suggests Carmil1 expression suppresses behavioral POE, and Airn suppresses POE on Carmil1 expression. A significant diet-by-POE was observed on one behavior, one imprinted gene, and over a dozen non-imprinted genes. Beyond our particular results, our study demonstrates a reciprocal F1 hybrid framework for studying POE and environment-by-POE on behavior.

scholarly journals Ongoing production of low-fitness hybrids limits range overlap between divergent cryptic species

2021 ◽  
Author(s):  
Else K. Mikkelsen ◽  
Darren Irwin
Keyword(s):  
First Generation ◽  
Sex Chromosome ◽  
Genomic Variation ◽  
F1 Hybrids ◽  
The Pacific ◽  
Species Pairs ◽  
Genetic Clusters ◽  
Range Overlap ◽  
Female Specific

AbstractContact zones between recently-diverged taxa provide opportunities to examine the causes of reproductive isolation and to examine the processes that determine whether two species can coexist over a broad region. The Pacific Wren (Troglodytes pacificus) and the Winter Wren (Troglodytes hiemalis) are two morphologically similar songbird species that started diverging about 4 million years ago, older than most sister species pairs. The ranges of these species come into narrow contact in western Canada, where the two species remain distinct in sympatry. To assess evidence for differentiation, hybridization, and introgression in this system, we examined variation in over 250,000 single nucleotide polymorphism markers distributed across the genomes of the two species. The two species formed highly divergent genetic clusters, consistent with long-term differentiation. In a set of 75 individuals from allopatry and sympatry, two first-generation hybrids (i.e., F1’s) were detected, indicating only moderate levels of assortative mating between these taxa. We found no recent backcrosses or F2’s or other evidence of recent breeding success of F1 hybrids, indicating very low or zero fitness of F1 hybrids. Examination of genomic variation shows evidence for only a single backcrossing event in the distant past. The sizeable rate of hybridization combined with very low fitness of F1 hybrids is expected to result in a population sink in the contact zone, largely explaining the narrow overlap of the two species. If such dynamics are common in nature, they could explain the narrow range overlap often observed between pairs of closely related species. Additionally, we present evidence for a rare duplication of a large chromosomal segment from an autosome to the W chromosome, the female-specific sex chromosome in birds.

Morphology and fitness components of wild × crop F1 hybrids of Sorghum bicolor (L.) in Ethiopia: implications for survival and introgression of crop genes in the wild pool

2013 ◽  
Vol 11 (3) ◽  
pp. 196-205 ◽  
Author(s):  
Asfaw Adugna ◽  
Endashaw Bekele
Keyword(s):  
Risk Assessment ◽  
Natural Hybridization ◽  
Relative Fitness ◽  
F1 Hybrids ◽  
Transgenic Crop ◽  
Fitness Components ◽  
Crop Species ◽  
In The Wild ◽  
Sorghum Bicolor L ◽  
Made In

Natural hybridization between wild/weedy and crop species often results in rare hybrids, which can be more weedy and difficult to control. Moreover, the advent of transgenic crop plants raises questions of biosafety risk assessment on the consequences of rare hybrids with possible fitness enhancing genes on the environment. This study aimed at measuring the fitness components of wild–crop sorghum hybrids for various juvenile survival and adult morphological and fertility characters as part of the risk assessment of transgenic sorghum in Africa where the crop was believed to have first domesticated and serves as the major staple. Out of a pool of hybrids made in 2010 from 23 wild sorghum accessions and two released cultivated sorghum varieties using hand emasculation techniques, seven were selected for the field study of their fitness components in 2011. The study confirmed that crop–wild hybrids of sorghum are fertile. Two approaches were followed (relative fitness and mid-parent heterosis) which showed that most of the hybrids were as fit as their wild parents, and in some cases they showed mid-parent heterosis for the measured traits. The results of this study highlighted a potential risk that hybrids carrying crop genes (including herbicide resistance transgenes) could pose because they could be more weedy than their wild/weedy parents if transgenic sorghum is deployed in regions where the wild and cultivated sorghum populations coexist, such as in Ethiopia and in other parts of Africa.

scholarly journals Gene Flow Between Introduced and Native Eucalyptus Species: Morphological Analysis of Tri-Species and Backcross Hybrids Involving E. nitens

2007 ◽  
Vol 56 (1-6) ◽  
pp. 127-133 ◽  
Author(s):  
C. Barbour ◽  
B. M. Potts ◽  
R. E. Vaillancourt
Keyword(s):  
Gene Flow ◽  
Second Generation ◽  
Current Work ◽  
F1 Hybrids ◽  
Morphological Identification ◽  
Eucalyptus Species ◽  
Pure Species ◽  
Backcross Hybrids ◽  
In The Wild ◽  
Species Hybrids

Summary Morphometric analyses were conducted on second-generation tri-species and backcross hybrids in Eucalyptus. These hybrids were all produced using pollen from two E. nitens x cordata F1 hybrids and controlled pollination techniques. Tri-species hybrids were created with E. gunnii, E. ovata and E. viminalis as females, while backcrosses were produced with E. cordata. Multivariate analysis of seedling characteristics indicated that eighty percent of the backcross hybrids fell within the morphological range of E. cordata. All three cross combinations of the tri-species hybrids were biased away from E. nitens and towards their maternal parent and E. cordata. The inclusion of data for first-generation (F1) hybrids between the pure parental species in the current work showed the F1’s to be easily distinguishable from pure species, compared to second-generation hybrids. The use of morphology for detecting second-generation hybridisation involving exotic plantation species and native eucalypt populations will therefore be unreliable, and identifies a need for preventing second-generation hybrids from establish in the wild. The current work, nevertheless, provides further demonstration of the effectiveness of morphological identification of F1 hybrids. The easy recognition of F1 hybrids will be useful in identifying sites and species at risk of exotic gene flow and enable the development of weeding programs that focus on removing exotic hybrids in the wild.

Pollination in alpine Norway: flowering phenology, insect visitors, and visitation rates in two plant communities

1993 ◽  
Vol 71 (8) ◽  
pp. 1072-1079 ◽  
Author(s):  
Ørjan Totland
Keyword(s):  
Plant Communities ◽  
Interspecific Interactions ◽  
Flowering Phenology ◽  
Alpine Plant ◽  
Visitation Rates ◽  
Species Pairs ◽  
Alpine Plant Communities ◽  
Selection For ◽  
Insect Visitors ◽  
Key Words Alpine

Pollination studies in European alpine communities are few. The objective of this study was to describe the pollination ecology in two alpine plant communities at Finse, southwestern Norway. Because of late snowmelt and early winter at Finse, the time available for flowering and seed maturation is restricted. Flowering was concentrated at the beginning of the season in both communities, and large overlaps in flowering time were found for most species. In one of the communities, flowering peaks were significantly clumped, whereas in the other they were randomly distributed through the season. However, in this community, five insect-pollinated species flowered simultaneously early in the season. Diptera almost exclusively dominated the visitor assemblage. Most plant species pairs had high overlaps in flower visitor species. Species flowering simultaneously attracted the same visitor species. In one community, eight species pairs flowered sequentially and shared visitors. Visitation rates were highest at the lowest elevated site. The results are compared with those obtained in other alpine areas. It is argued that selection for an early flowering is probably stronger than selection pressures resulting from interspecific interactions. Key words: alpine, Diptera, flowering phenology, flower visitors, season length, visitation rate.

Use of Gas Chromatograms of the Essential Leaf Oils of the Genus Eucalyptus for Taxonomic Purposes

1997 ◽  
Vol 45 (1) ◽  
pp. 1 ◽  
Author(s):  
Peter J. Dunlop ◽  
Caroline M. Bignell ◽  
D. Brynn Hibbert
Keyword(s):  
Discriminant Analysis ◽  
Linear Discriminant Analysis ◽  
Vacuum Distillation ◽  
Principal Component ◽  
Analytical Techniques ◽  
Hierarchical Cluster ◽  
Eucalyptus Species ◽  
Linear Discriminant ◽  
Genus Eucalyptus

Using morphological observations, botanists have classified Eucalyptus species into characteristic series. A new vacuum distillation technique has been employed to obtain the characteristic leaf oils, which are very close to their in vivo compositions, from 35 species belonging to series Tetrapterae, series Torquatae and series Rufispermae. Accurate gas chromatograms have been obtained for each species and three analytical techniques (principal component analysis (PCA), hierarchical cluster analysis (CA) and linear discriminant analysis (LDA)) have been used to process these chromatograms to see if agreement with these classifications could be achieved without using any auxiliary morphometric data. For the species chosen for the present study, linear discriminant analysis was the most successful in assigning species to their present botanic classifications. These analytical methods were also used with some success in searching for groupings within a series and within a species.

Sign in / Sign up

Export Citation Format

Share Document