scholarly journals Nature of 2n Gamete Formation and Mode of Inheritance in Interspecific Hybrids of Diploid Vaccinium darrowii and Tetraploid V. corymbosum

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 808E-808
Author(s):  
Luping Qu ◽  
J.F. Hancock
Keyword(s):  
Interspecific Hybrids ◽  
Rapd Markers ◽  
2N Gametes ◽  
Diploid Population ◽  
A Value ◽  
Tetraploid Hybrid ◽  
Gamete Formation ◽  
2N Gamete ◽  
Segregating Population ◽  
Mode Of Inheritance

RAPD markers were used to determine the level of heterozygosity transmitted via 2n gametes from V. darrowi cv. Florida 4b (Fla 4B) to interspecific hybrids with tetraploid V. corymbosum cv. Bluecrop. The tetraploid hybrid US 75 was found to contain 70.6% of Fla 4B's heterozygosity, a value consistent with a first division restitution (FDR) mode of 2n gamete production. Crossovers during 2n gamete formation were evidenced by the absence of 16 dominant alleles of Fla 4B in US 75, and direct tests of segregation in a diploid population involving Fla 4B. RAPD markers that were present in both Fla 4B and US 75 were used to determine the mode of inheritance in a segregating population of US 75 × V. corymbosum cv. Bluetta. More than 30 homozygous pairs of alleles were located that segregated in a 5:1 ratio, indicating US 75 undergoes tetrasomic inheritance.

Genetic significance of mode of polyploidization: somatic doubling or 2n gametes?

Genome ◽  
1991 ◽  
Vol 34 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Kazuo Watanabe ◽  
Stanley J. Peloquin ◽  
Masatoshi Endo
Keyword(s):  
Combining Ability ◽  
Allelic Diversity ◽  
2N Gametes ◽  
Genotypic Diversity ◽  
P Value ◽  
Sexual Polyploidization ◽  
Gamete Formation ◽  
Single Exchange ◽  
Genetic Significance ◽  
2N Gamete

Computer simulation was undertaken to compare the genetic consequences of asexual (somatic doubling) and sexual (2n gametes) polyploidization. The coefficient of inbreeding at a locus, the number and frequency of genotypes at a locus, and the proportion of tri- and tetra-allelic genotypes were considered. The factors considered to estimate the genetic consequences were (i) mechanisms of sexual polyploidization, by first division restitution (FDR) × second division restitution (SDR), FDR × FDR, or SDR × SDR; (ii) position of the locus in relation to the centromere, which affects the gametic output in 2n gamete formation and thus the probability of single-exchange tetrads in meiosis during 2n gamete formation (p value); and (iii) allelic diversity at a locus. In comparing asexual and sexual polyploidization, regardless of the position of a locus in relation to the centromere, sexual polyploidization generally indicated less inbreeding, more genotypic diversity, and a higher proportion of tri- and tetra-allelic genotypes. When allelic diversity at a locus was increased, these characteristics were even more prominent. When only two alleles are possible at a locus, somatic doubling would not be inferior to sexual polyploidization. Overall results favored SDR × FDR and FDR × FDR as a mode and mechanisms of polyploidization. The genetic variations produced by 2n gametes could be attributed to "combining ability of 2n gametes."Key words: asexual polyploidization, sexual polyploidization, inbreeding, heterozygosity, combining ability of 2n gametes.

scholarly journals Genomics-based discrimination of 2n gamete formation mechanisms in polyploids: a case study in nonaploid Diospyros kaki ‘Akiou’

2021 ◽  
Author(s):  
Peng Sun ◽  
Soichiro Nishiyama ◽  
Hideaki Asakuma ◽  
Roeland E Voorrips ◽  
Jianmin Fu ◽  
...  
Keyword(s):  
2N Gametes ◽  
Unreduced Gametes ◽  
Formation Mechanisms ◽  
Common Source ◽  
Diospyros Kaki ◽  
Normal Female ◽  
Gamete Formation ◽  
Allele Dosage ◽  
2N Gamete ◽  
Gamete Production

Abstract Unreduced gametes (2n gametes), possessing double the haploid genome, whatever ploidy that happens to be, are a common source of ploidy variation in plant populations. First and second division restitution (FDR and SDR) are the dominant mechanisms of 2n gamete production; all else being equal, FDR gametes have a higher degree of heterozygosity, thus they are advantageous in breeding. The discrimination of these mechanisms from the consequence of hybridization is challenging, especially in higher polyploids, and usually requires information on centromere location. In this study, we propose a genotyping-based strategy to uncover the mechanisms of 2n gamete formation in progeny that has a higher ploidy than its parents. Simulation of 2n gamete production revealed that FDR and SDR pathways can be discriminated based on allele transmission patterns alone without information on centromere location. We applied this strategy to study the formation mechanism of a nonaploid Diospyros kaki ‘Akiou’, which was bred via hybridization between D. kaki hexaploid cultivars. The result demonstrated that ‘Akiou’ was derived from the fertilization of a normal female gamete by a 2n male gamete, and that this 2n gamete was produced through FDR. Consequently, the distinct duplex transmission pattern in the FDR gamete enabled us to infer the genomic characteristics of polyploid persimmon. The method could be tested only for the plant being polypoid, which allows for the ability to discriminate causes of 2n gamete formation using allele dosage in progeny, and will be useful in future studies of polyploid genomics.

MOLECULAR CHARACTERIZATION OF INTERSPECIFIC HYBRIDS OF SCENTED ROSES USING RAPD MARKERS

2007 ◽  
pp. 175-179
Author(s):  
N. Kaur ◽  
R.K. Sharma ◽  
D. Dhyani ◽  
S. Karthigeyan ◽  
P.S. Ahuja
Keyword(s):  
Molecular Characterization ◽  
Interspecific Hybrids ◽  
Rapd Markers

scholarly journals Sorghum bicolor x S. halepense interspecific hybridization is influenced by the frequency of 2n gametes in S. bicolor

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
George L. Hodnett ◽  
Sara Ohadi ◽  
N. Ace Pugh ◽  
Muthukumar V. Bagavathiannan ◽  
William L. Rooney
Keyword(s):  
Gene Flow ◽  
Sorghum Bicolor ◽  
Interspecific Hybridization ◽  
2N Gametes ◽  
Female Parent ◽  
Optimum Conditions ◽  
Male Sterile ◽  
Chemically Induced ◽  
Parent Selection ◽  
2N Gamete

AbstractTetraploid johnsongrass [Sorghum halepense (L.) Pers.] is a sexually-compatible weedy relative of diploid sorghum [Sorghum bicolor (L.) Moench]. To determine the extent of interspecific hybridization between male sterile grain sorghum and johnsongrass and the ploidy of their progeny, cytoplasmic (CMS), genetic (GMS) and chemically induced male sterile lines of Tx623 and Tx631 were pollinated with johnsongrass pollen. At maturity 1% and 0.07% of the developing seeds of Tx623 and Tx631 respectively were recovered. Ninety-one percent of recovered hybrids were tetraploid and two percent were triploid, the tetraploids resulting from 2n gametes present in the sorghum female parent. Their formation appears to be genotype dependent as more tetraploids were recovered from Tx623 than Tx631. Because a tetraploid sorghum x johnsongrass hybrid has a balanced genome, they are male and female fertile providing opportunities for gene flow between the two species. Given the differences in 2n gamete formation among Tx623 and Tx631, seed parent selection may be one way of reducing the likelihood of gene flow. These studies were conducted in controlled and optimum conditions; the actual outcrossing rate in natural conditions is expected to be much lower. More studies are needed to assess the rates of hybridization, fitness, and fertility of the progeny under field conditions.

Evidence for the existence of endosperm balance number in the true clovers (Trifolium spp.)

1986 ◽  
Vol 28 (4) ◽  
pp. 581-586 ◽  
Author(s):  
W. A. Parrott ◽  
R. R. Smith
Keyword(s):  
Ploidy Level ◽  
Related Species ◽  
Interspecific Hybrids ◽  
2N Gametes ◽  
Endosperm Development ◽  
Individual Species ◽  
Interspecific Crosses ◽  
Endosperm Balance Number ◽  
Endosperm Tissue ◽  
2N Eggs

The endosperm balance number (EBN) hypothesis was first advanced to explain results from interspecific crosses in Solanum and later in Impatiens. According to the EBN hypothesis, normal endosperm development following intra- or inter-specific crosses depends on having a ratio of two EBNs from the female to one EBN from the male in the endosperm tissue. EBNs may differ among related species. Successful hybrids can be obtained between species with the same EBN. The ploidy level of an individual species can be varied to modify its EBN, making it cross compatible with a species sharing its modified EBN. Interspecific crosses within Trifolium have been limited and difficult. Crosses reported in the literature, including evidence from our own study, suggest that EBN is operating in Trifolium and have been used to assign EBN numbers to some clover species. The use of 2n eggs enabled two species, differing in EBN, to be crossed. An understanding of the EBN mechanism that operates in Trifolium should make successful interspecific hybrids easier to obtain in the future.Key words: endosperm balance number, hybrids (interspecific), 2n gametes, Trifolium.

Potential of trispecies bridge crosses and random amplified polymorphic DNA markers for introgression of Medicago daghestanica and M. pironae germplasm into alfalfa (M. sativa)

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 594-601 ◽  
Author(s):  
T. J. McCoy ◽  
C. S. Echt
Keyword(s):  
Embryo Culture ◽  
Interspecific Hybrids ◽  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Embryo Rescue ◽  
Backcross Progeny ◽  
Culture Technique ◽  
Randomly Amplified Polymorphic Dna ◽  
Bivalent Chromosome ◽  
Diploid Level

This report describes the production and cytology of the first interspecific hybrids between cultivated alfalfa (Medicago sativa L.) at the diploid level (2n = 2x = 16) and the diploid (2n = 2x = 16) perennial species M. daghestanica and M. pironae. An ovule–embryo culture technique was required to rescue hybrid embryos and all hybrids were diploid. Predominately bivalent chromosome pairing was observed at meiotic metaphase. All F1 hybrids were male and female sterile and no species backcross progeny could be produced. We discovered that trispecies hybrids could be efficiently recovered via crossing diploid F1 interspecific hybrids of M. sativa × M. rupestris with either M. daghestanica or M. pironae. Ovule–embryo culture was also required to recover these trispecies hybrids with recovery efficiency of trispecies hybrids about 10 times greater than for bispecies hybrids. Most chromosomes paired as bivalents in the trispecies hybrids. Importantly, progeny can be recovered from crossing the trispecies hybrids with M. sativa. Therefore, the M. sativa × M. rupestris hybrids provide a bridge cross to potential introgression of M. daghestanica or M. pironae germplasm. Analysis of randomly amplified polymorphic DNA (RAPD) markers in the trispecies hybrids indicates that RAPD markers offer considerable potential for assaying germplasm introgression following complex hybridizations of the type reported here.Key words: randomly amplified polymorphic DNA, Medicago interspecific hybrids, embryo rescue.

Maternal inheritance of the chloroplast genome in Eucalyptus globulus and interspecific hybrids

Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 831-835 ◽  
Author(s):  
Gay E McKinnon ◽  
René E Vaillancourt ◽  
Paul A Tilyard ◽  
Brad M Potts
Keyword(s):  
Molecular Marker ◽  
Interspecific Hybrid ◽  
Eucalyptus Globulus ◽  
Interspecific Hybrids ◽  
Maternal Inheritance ◽  
Genetic Manipulation ◽  
Specific Marker ◽  
Genetic Studies ◽  
Rapid Pcr ◽  
Mode Of Inheritance

The utility of chloroplast DNA (cpDNA) in Eucalyptus, either as a molecular marker for genetic studies or as a potential vehicle for genetic manipulation, is based on knowledge of its mode of inheritance. Chloroplast inheritance in angiosperms can vary among and within species, and anomalous inheritance has been reported in some interspecific-hybrid combinations. In Eucalyptus, abnormalities of pollen-tube growth occur in a number of interspecific-hybrid combinations, and this might increase the likelihood of anomalous chloroplast transmission. We used a rapid PCR technique to determine chloroplast heritability in 425 progeny of Eucalyptus, comprising 194 progeny of the premier pulpwood species E. globulus and 231 interspecific hybrids between E. globulus and E. nitens (F1, F2, and backcrosses). At this sampling intensity, no pollen-mediated transmission of cpDNA was found in any of the 40 families tested. The results are discussed with reference to chloroplast engineering and the use of cpDNA as a seed-specific marker in phylogeographic studies of Eucalyptus.Key words: organelle, plastids, uniparental, maternal inheritance, interspecific hybrids.

Sign in / Sign up

Export Citation Format

Share Document