scholarly journals Fertile Intersectional F1 Hybrids of 4x Vaccinium meridionale (Section Pyxothamnus) and Highbush Blueberry, V. corymbosum (Section Cyanococcus)

HortScience ◽  
2021 ◽  
pp. 1-6
Author(s):  
Mark K. Ehlenfeldt ◽  
James L. Luteyn
Keyword(s):  
South America ◽  
Male Fertility ◽  
First Generation ◽  
Seedling Stage ◽  
F1 Hybrids ◽  
Highbush Blueberry ◽  
Pollen Production ◽  
Tetraploid Species ◽  
Plant Structure ◽  
Potential Value

Vaccinium meridionale (section Pyxothamnus), a tetraploid species native to higher altitude locations in Jamaica, Colombia, and Venezuela, is of considerable interest to blueberry breeders for its profuse, concentrated flowering and monopodial plant structure, both of which may be useful in breeding for mechanical harvest. In this study, tetraploid V. meridionale was successfully hybridized as a male with 4x V. corymbosum (section Cyanococcus, highbush blueberry). The first-generation hybrids with highbush blueberry selections were intermediate in morphology and notably vigorous. The 4x F1 hybrids displayed variable branching structure, dormancy, prolificacy, fruit wax, etc.; however, most appear to be deciduous to semi-evergreen, with small, dark-colored fruit. The F1 hybrids displayed good fertility as females in backcrosses to 4x highbush and these crosses have produced numerous offspring morphologically indistinguishable from 4x highbush at the seedling stage. Evaluations of male fertility found variation for pollen production and quality but, significantly, found some clones with very good shed, high stainability, and almost complete tetrad production. The fertility suggests that these hybrids, despite being derived from intersectional crosses, might be conventionally used without significant difficulty. These hybrids also have potential value for the nascent V. meridionale breeding efforts occurring in Colombia, South America.

scholarly journals Unravelling the hybrid vigor in domestic equids: the effect of hybridization on bone shape variation and covariation

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Pauline Hanot ◽  
Anthony Herrel ◽  
Claude Guintard ◽  
Raphaël Cornette
Keyword(s):  
First Generation ◽  
Shape Change ◽  
Morphological Integration ◽  
Hybrid Vigor ◽  
F1 Hybrids ◽  
Shape Variation ◽  
Locomotor System ◽  
Domestic Horses ◽  
Functional Mechanisms ◽  
Underlying Processes

Abstract Background Hybridization has been widely practiced in plant and animal breeding as a means to enhance the quality and fitness of the organisms. In domestic equids, this hybrid vigor takes the form of improved physical and physiological characteristics, notably for strength or endurance. Because the offspring of horse and donkey is generally sterile, this widely recognized vigor is expressed in the first generation (F1). However, in the absence of recombination between the two parental genomes, F1 hybrids can be expected to be phenotypically intermediate between their parents which could potentially restrict the possibilities of an increase in overall fitness. In this study, we examine the morphology of the main limb bones of domestic horses, donkeys and their hybrids to investigate the phenotypic impact of hybridization on the locomotor system. We explore bone shape variation and covariation to gain insights into the morphological and functional expressions of the hybrid vigor commonly described in domestic equids. Results Our data reveal the occurrence of transgressive effects on several bones in the F1 generation. The patterns of morphological integration further demonstrate that the developmental processes producing covariation are not disrupted by hybridization, contrary to functional ones. Conclusions These results suggest that an increase in overall fitness could be related to more flexibility in shape change in hybrids, except for the main forelimb long bones of which the morphology is strongly driven by muscle interactions. More broadly, this study illustrates the interest of investigating not only bone shape variation but also underlying processes, in order to contribute to better understanding how developmental and functional mechanisms are affected by hybridization.

scholarly journals Успадкування господарсько цінних ознак у гібридів F1 квасолі звичайної в умовах Лівобережної частини Лісостепу України

2013 ◽  
pp. 33-36
Author(s):  
С. І. Силенко ◽  
О. С. Силенко
Keyword(s):  
Seed Yield ◽  
First Generation ◽  
Seed Mass ◽  
Growing Season ◽  
F1 Hybrids ◽  
Lower Tier ◽  
Number Of Seeds

Доведено, що ступінь фенотипового домінування у гібридів F1 може варіювати від hp > +1 до hp < -1 залежно від компонентів схрещування. Встановлено, що переважна більшість гібридів F1 тривалість веґетаційного періоду та його міжфазних періодів успадковують за типами позитивного наддомінування та позитивним домінуванням. Успадкування висоти рослин відбувається за типами позитивного домінування, проміжного успадкування та за типом негативного домінування. Характер успадкування висоти прикріплення нижнього ярусу бобів у значній мірі визначається поєднанням батьківських компонентів. Так, у першому поколінні у гібридних комбінаціях спостерігається явище наддомінування. За ознаками урожайності та її елементів (урожайність насіння, маса насіння з рослини, маса 1000 насінин, кількість бобів на рослині, кількість насінин із рослини, кількість насінин у бобі) у всіх без виключення гібридів першого покоління спостерігався гетерозис. It was demonstrated that the degree of phenotypic predominance in F1 hybrids can vary from hp to hp < +1 > -1 depending on mating components. The vast majority of the F1 hybrids inherit the length of the growing season and its interphase by type of over& positive dominance. F1 hybrids inherit the height of plants by types of positive dominance, intermediate inheritance and negative domination. The height of the attachment of the lower tier of the beans is largely determined by a combination of parent components. Thus, in the first generation in hybrid combinations there is the phenomenon of over dominance. Due to the yield and its components (seed yield, seed mass per plant, 1000 seeds, number of beans per plant, number of seeds per plant, number of seeds per seedpod) in all first generation hybrids heterosis is observed.

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.

scholarly journals The study of the nature of the inheritance of quantitative traits in F1 hybrids of winter soft wheat

2020 ◽  
Vol 17 ◽  
pp. 00084
Author(s):  
Olga Antoshina ◽  
Julia Odnodushnova ◽  
Gennadiy Fadkin ◽  
Irina Kondakova ◽  
Olga Fedosova
Keyword(s):  
Quantitative Traits ◽  
First Generation ◽  
Grain Weight ◽  
Soft Wheat ◽  
F1 Hybrids ◽  
Complex Nature ◽  
Intraspecific Hybridization ◽  
Quantitative Characteristics ◽  
Economically Valuable Traits ◽  
Ear Number

In the conditions of the south of the Nonchernozem Zone, intraspecific hybridization of winter soft wheat was carried out. When selecting parental forms used in crossing, special attention was paid to such economically valuable traits as productive tilling capacity, the number of grains and the mass of grain per spike. The true (Htru) and hypothetical heterosis (Hhyp) on the basis of “plant height”, “length of the lower internode”, “length of the upper internode”, “general tilling capacity”, “productive tilling capacity”, “spike length”, “number of spikelets”, “number of grains” and “grain weight per spike” were determined. It was established that the inheritance of quantitative traits in hybrids of the first generation was distinguished by the complex nature of distribution by types. Studies have made possible to identify 5 hybrid combinations F1, in which the effect of heterosis manifests itself simultaneously on five quantitative characteristics (ear length, number of spikelets per ear, number of grains per ear, grain weight per ear, mass grain from a plant).

Peer mentoring to support first-generation low-income college students

2018 ◽  
Vol 99 (7) ◽  
pp. 47-51 ◽  
Author(s):  
Sean Plaskett ◽  
Diksha Bali ◽  
Michael J. Nakkula ◽  
John Harris
Keyword(s):  
Low Income ◽  
Peer Mentoring ◽  
First Generation ◽  
Mentoring Program ◽  
Peer Mentors ◽  
Qualitative Investigation ◽  
Potential Value ◽  
Formidable Challenge ◽  
High School To College ◽  
Low Income College Students

Transitioning from high school to college can be a formidable challenge, especially for students who are the first in their family to attend college (first-generation) and/or are from low-income backgrounds. The authors’ qualitative investigation of a college mentoring program illuminates the potential value of relatable peer mentors in helping these students get off to a good start.

scholarly journals The role of allelic and nonallelic interactions of genes in the mechanism of heterosis

2019 ◽  
Vol 24 ◽  
pp. 177-182
Author(s):  
S. G. Hablak ◽  
Ya. A. Abdullaeva ◽  
L. O. Ryabovol ◽  
Ya. S. Ryabovol
Keyword(s):  
First Generation ◽  
Gene Interaction ◽  
Point Of View ◽  
F1 Hybrids ◽  
Heterosis Effect ◽  
Nonallelic Interactions ◽  
F2 Generation ◽  
Mutant Lines ◽  
Polymeric Interaction

Aim. Studying the heterosis effect from the point of view of allelic and nonallelic gene interaction in F1 hybrids from crossing the arabidopsis ecotypes Col-0 and La-0. Methods. Hybridological method of crossing mutant lines and analysis of the inheritance of the signs of the root system. Results. When plants of different races Col-0 and La-0 cross in the F2 generation, polymeric interaction of genes occurs. In that case splitting in F2 goes in the ratio 15: 1. At the same time, hybrids of the first generation exhibit heterosis, which is manifested in a more powerful development of a rosette of leaves in comparison with the initial forms. Conclusions. The emergence of heterosis in hybrids of the first generation can be explained on the basis of the allelic and nonallelic gene interaction, which creates a favorable combination of genes during hybridization, causing the best manifestation of an economically valuable trait. Keywords: Arabidopsis thaliana (L.) Heynh., heterosis, gene, mutation, race.

scholarly journals THE PROVISION OF PASTURE LEGUMES FOR DIFFICULT ENVIRONMENTS

1987 ◽  
pp. 83-88
Author(s):  
R.L. Burt ◽  
M.B. Forde
Keyword(s):  
New Species ◽  
New Zealand ◽  
South America ◽  
First Generation ◽  
Plant Introduction ◽  
Simple Approach ◽  
European Species ◽  
Pasture Legumes ◽  
Different Types ◽  
A New Species

Early plant introduction in Australia and NZ involved familiar European species and simple general principles. 'First-generation' pasture cultivars in both countries were based on naturalized or cultivated material originally brought by colonists. Later, imported material was systematically used to improve these established varieties and produce 'second-generation' cultivars more closely adapted to local ecological conditions and agronomic systems. This simple approach proved inadequate for new and difficult environments which required different types of plant, and new species were sometimes tried and discarded prematurely because their potential was not fully displayed in the limited material initially available. Experience with Sfylosanthes in Australia shows that full suites of germplasm are necessary to evaluate a new species properly, and that such material should be deliberately and systematically collected from areas of similar or more extreme climate, particular attention being paid to edaphic characteristics. To obtain suitable legumes for the cold dry high country of the South Island collections from homologous regions in places such as Chile, Argentina, Kashmir, and the USSR may be useful. Keywords: plant introduction, Stylosanthes, Lotus, South America, Australia, New Zealand

The tadpole of Pleurodema cordobae Valetti, Salas & Martino, 2009 (Anura: Leiuperidae) from Córdoba, Argentina

Zootaxa ◽  
2013 ◽  
Vol 3635 (4) ◽  
pp. 498-500 ◽  
Author(s):  
MANUEL A. OTERO ◽  
PABLO R. GRENAT ◽  
JULIAN A. VALETTI ◽  
NANCY E. SALAS ◽  
ADOLFO L. MARTINO
Keyword(s):  
New Species ◽  
South America ◽  
Cryptic Species ◽  
External Morphology ◽  
Tetraploid Species ◽  
Southern Chile ◽  
Oral Disc

The frog genus Pleurodema Tschudi, 1838 is distributed from Panama throughout South America to southern Chile and Argentina and currently is represented by 15 species, of which 10 have been recorded in Argentina (Faivovich et al. 2012). Recently, Valetti et al. (2009) re-described the tetraploid species P. kriegi and described a related cryptic species, the octoploid Pleurodema cordobae. These species are endemic of the Sierra Grande of Córdoba (Ferraro & Casagranda 2009; Valetti et al. 2009; Valetti et al. 2011) and together with the tetraploid P. bibrioni comprise a clade of polyploid cryptic species within the genus (Faivovich et al. 2012). The external morphology has been described for the tadpoles of P. bibrioni and P. kriegi by Kolenc et al. (2009), but the tadpole of P. cordobae remains undescribed. The aim of this work is to describe the larval external morphology and oral disc of new species P. cordobae.

Male fertility and 2n pollen production in haploid-wild species hybrids

1985 ◽  
Vol 62 (9) ◽  
pp. 479-487 ◽  
Author(s):  
Shelley A. Hermundstad ◽  
S. J. Peloquin
Keyword(s):  
Wild Species ◽  
Male Fertility ◽  
Pollen Production ◽  
2N Pollen ◽  
Species Hybrids

Temperature and genotypic effects on the expression of pol cytoplasmic male sterility in summer rape

1991 ◽  
Vol 71 (3) ◽  
pp. 655-661 ◽  
Author(s):  
D. R. Burns ◽  
R. Scarth ◽  
P. B. E. McVetty
Keyword(s):  
High Temperature ◽  
Brassica Napus ◽  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Male Fertility ◽  
Inbred Lines ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Controlled Environment ◽  
Pollen Production

The effect of high temperature treatment on the expression of cytoplasmic male sterility (CMS) was studied using inbred lines of four summer rape (Brassica napus L.) cultivars. The nuclear genotypes of inbred lines from each of the cultivars Karat, Lergo, Marnoo and Regent were evaluated for their ability to maintain pollen sterility in the pol cytoplasm. Seven days' exposure to day/night temperatures of 30/24 °C in a controlled environment led to increased pollen production in all of the F1 populations (F1's) in the study. Maximum reversion to male fertility occurred 6–13 d after removal from the high temperature treatment. There was a significant linear relationship between daily mean temperatures in the field and mean male sterility index (MSI). In Lergo, Marnoo and Regent F1's, the effect of high temperatures on male sterility expression in terms of days to maximum pollen production in the field was accurately predicted by the values obtained in the controlled environment study. For the Karat F1's, the maximum response in the field occurred later than in the controlled environment. Variation in the stability of male sterility was evident in the F1's, indicating the presence of different maintainer genes among the inbred lines of each cultivar. The absence of environment-by-line interactions in the F1's of three cultivars indicated a high degree of stability for this trait. Selection for maintenance of high levels of male sterility may therefore be possible. Key words: Brassica napus, male fertility reversion

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