Synaptic mutants in potato, Solanum tuberosum L. III. Effect of the Ds-1/ds-1 locus (desynapsis) on genetic recombination in male and female meiosis

Genome ◽  
1991 ◽  
Vol 34 (1) ◽  
pp. 121-130 ◽  
Author(s):  
E. Jongedijk ◽  
R. C. B. Hutten ◽  
J. M. A. S. A. van der Wolk ◽  
S. I. J. Schuurmans Stekhoven
Keyword(s):  
Genetic Recombination ◽  
Solanum Tuberosum L ◽  
2N Gametes ◽  
Potato Seed ◽  
Genetic Constitution ◽  
True Potato Seed ◽  
Female Meiosis ◽  
Recombination Rates ◽  
Male And Female ◽  
Tetraploid Progeny

By applying half-tetrad analysis to segregating tetraploid progeny that had been raised from 2x–4x and 2x–2x crosses, five marker loci (ym, y, Got-1, Got-2, and ds-1) were mapped to their respective centromeres in male and female meiosis of both normal synaptic and desynaptic (ds-1ds-1) diploid potato clones. Significant sex differences in genetic recombination for these loci did not occur in either normal plants or desynaptic mutants, which suggests that genetic exchange in both the sexes is governed by the same control system. In desynaptic mutants a severe reduction in crossing-over was observed for ym and.y (83.7 an 90.0% reduction, respectively), whereas recombination rates for Got-2 appeared to have systematically, although not significantly, increased. The ds-1 gene was concluded to substantially reduce the overall chiasma frequency and to differentially alter chiasma distribution along individual chromosomes. Based on segregation ratios in progeny from different types of testcrosses, first division restitution (FDR) and second division restitution (SDR) 2n gametes formed by normal synaptic plants were estimated to transmit on average about 82.7 and 36.1 %, respectively, of the parental heterozygosity to tetraploids. With desynapsis the average amount of heterozygosity transmitted by FDR 2n gametes amounted to 94.1%. SDR 2n gametes from desynaptic mutants are sterile as a result of aneuploidy. The ds-1 gene was demonstrated to particularly enhance the ability of FDR 2n gametes to preserve the genetic constitution of diploid parental clones with a minimum amount of reassortment. The potential value and limitations of the ds-1 gene for the production of true potato seed varieties and the experimental induction of diplosporic apomixis are discussed.Key words: Solanum, genetic markers, gene–centromere mapping, desynapsis, reduced recombination.

Use of half-tetrad analysis to discriminate between two types of 2n egg formation in a potato haploid

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 741-745 ◽  
Author(s):  
Joanna E. Werner ◽  
David S. Douches ◽  
Rosanna Freyre
Keyword(s):  
Solanum Tuberosum L ◽  
2N Gametes ◽  
Breeding Value ◽  
Tetrad Analysis ◽  
Recombination Rates ◽  
First Division Restitution ◽  
Egg Formation ◽  
Second Division Restitution ◽  
2N Eggs ◽  
Tetraploid Progeny

The ratio of the first division restitution (FDR) to second division restitution (SDR) 2n eggs was estimated in 4182t, a haploid (2n = 2x = 24) of Solanum tuberosum L. that produces 2n eggs by the two modes. The segregation of three genes previously mapped relative to their centromeres, Pgm-2 (2.0 cM), Mdh-1 (33.5 cM), and 6-Pgdh-3 (30.1 cM) was analyzed in the tetraploid offspring of a 2x × 4x cross. Based on the segregation of the Pgm-2 locus, 39.7% of the progeny originated from FDR 2n eggs and 60.3% from SDR. Segregation patterns of the two distal loci within the FDR-derived 4x subpopulation indicated that the gene–centromere recombination rate during megasporogenesis was significantly reduced for Mdh-1 when compared with a previous estimate during microsporogenesis. In the SDR-derived 4x subpopulation, the gene–centromere recombination rates for Mdh-1 and 6-Pgdh-3 were not significantly different from previous estimates. Tetraploid progeny generated from one 2x × 4x cross where the 2x parent produces 2n gametes by two modes can be used to make an unbiased comparison of the potential breeding value of FDR and SDR gametes.Key words: potato, megasporogenesis, first division restitution, second division restitution, isozyme.

Synaptic mutants in potato, Solanum tuberosum L. I. Expression and identity of genes for desynapsis

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 664-670 ◽  
Author(s):  
E. Jongedijk ◽  
M. S. Ramanna
Keyword(s):  
Solanum Tuberosum ◽  
Potato Breeding ◽  
Solanum Tuberosum L ◽  
2N Gametes ◽  
Solanum Species ◽  
Potato Seed ◽  
True Potato Seed ◽  
Recessive Inheritance ◽  
Potential Value ◽  
Specific Influence

For tuber-bearing Solanum species, six monogenic recessive synaptic mutants, designated sy-1, sy-2, sy-3, sy-4, ds, and dsc have been reported in the literature. In the present investigation no indication for the existence of the mutant sy-1, affecting megasporogenesis only, was found. The mutant ds was confirmed to display typical desynaptic behaviour in microsporogenesis and shown to similarly affect megasporogenesis. It furthermore proved to be allelic to the mutants sy-3 and dsc. It is proposed that the mutants sy-3, ds, and dsc be uniformly designated ds-1, whereas the remaining mutants sy-2 and sy-4 (possibly identical) may be designated simply as synaptic mutant until their actual identity has been established. The observed F1 segregations generally support monogenic recessive inheritance of ds-1. However, in one cross progeny the expected mutant phenotype was not clearly expressed in contrast with its reciprocal, which might indicate cross-specific influence of the cytoplasm on ds-1 expression. The potential value and limitations of desynaptic (ds-1ds-1) mutants for potato breeding and true potato seed production are discussed.Key words: Solanum, (de)synaptic mutants, microsporogenesis, megasporogenesis, 2n gametes.

scholarly journals Effect of Transplanting Dates and Plant Population on Growth Parameters of Potato (Solanum Tuberosum L.) Raised from True Potato Seed (Tps)

2014 ◽  
Vol 47 (1) ◽  
pp. 97-106
Author(s):  
D. Sen ◽  
A. Rakshit ◽  
D.C. Ghosh
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Solanum Tuberosum L ◽  
Plant Population ◽  
Potato Seed ◽  
True Potato Seed ◽  
Dry Matter Accumulation ◽  
Tuber Growth ◽  
Area Index ◽  
Tuber Bulking

ABSTRACT A field experiment was conducted during the rabi season of 2007- 2008 and 2008-2009 at Paschim Medinipore, West Bengal to study the effect of transplanting dates and plant population on growth parameters of potato raised from TPS. Dry matter accumulation per plant was more in early transplanted (December 3) and sparsely populated (60 cm x 15 cm) crop. The highest leaf area index was observed in early transplanted crop with closer spacing (40 cm x 10 cm) at 60 days after transplanting. The highest crop growth rate, tuber bulking rate and tuber growth rate values were also recorded in early and closely transplanted TPS crop between 45- 60 days after transplanting during both the years under investigation

Potato breeding with haploids and 2n gametes

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 1000-1004 ◽  
Author(s):  
S. J. Peloquin ◽  
Georgia L. Yerk ◽  
Joanna E. Werner ◽  
Elizabeth Darmo
Keyword(s):  
Genetic Diversity ◽  
Specific Gravity ◽  
Potato Breeding ◽  
Germ Plasm ◽  
Allelic Diversity ◽  
2N Gametes ◽  
Potato Seed ◽  
True Potato Seed ◽  
Breeding Method ◽  
Essential Components

Potato breeding methods that utilize haploids of Solanum tuberosum group Tuberosum or group Andigena and 2n gametes exploit the genetic diversity, including both valuable traits and allelic diversity, available in exotic germ plasm. Three essential components are involved: (i) the wild and cultivated 2x relatives of the cultivated 4x potato are a valuable source of genetic diversity; (ii) haploids (2n = 2x = 24) of cultivars (2n = 4x = 48) are effective in capturing diversity (germ plasm enhancement); (iii) 2n gametes, resulting from first division restitution, are an efficient method of transmitting this genetic diversity to cultivated 4x potatoes. Heterosis for total and marketable tuber yield and specific gravity occurs in 4x families from crosses between 4x cultivars and 2x haploid Tuberosum × 'Phureja' hybrids. Selected 4x clones from relatively small 4x × 2x families have been released as cultivars based on their earliness and heat tolerance in the tropics. Other 4x clones from 4x × 2x crosses, where the 2x parents were haploid – wild species hybrids, have good yield, excellent tuber type, high specific gravity, low reducing sugars, storage quality, and stress tolerance. The seedling vigor, uniformity, and large tuber yields of progeny from 4x × 2x crosses also makes this an effective breeding method for producing potatoes from true potato seed. This breeding method is also being successfully exploited in alfalfa, red clover, sweet potatoes, yams and several species of grasses, fruits, and ornamentals.Key words: potato, haploids, 2n gametes, germ plasm, allelic diversity.

Synaptic mutants in potato, Solanum tuberosum L. II. Concurrent reduction of chiasma frequencies in male and female meiosis of ds-1 (desynapsis) mutants

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1054-1062 ◽  
Author(s):  
E. Jongedijk ◽  
M. S. Ramanna
Keyword(s):  
Chiasma Frequency ◽  
Solanum Tuberosum L ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Frequency Variation ◽  
Female Meiosis ◽  
Male And Female ◽  
A Cell ◽  
The Mean ◽  
Mother Cells

Chiasma frequencies in pollen mother cells and megaspore mother cells from both normal and desynaptic (ds-1ds-1) diploid potato clones were estimated on the basis of chiasmate chromosome arm association in metaphase I. In desynaptic mutants both the mean chiasma and bivalent frequencies per cell and the mean chiasma frequency per bivalent proved to be significantly lower. Despite significant differences in within-cell chiasma frequency variation among and particularly between normal and desynaptic clones, no clear effects of the ds-1 gene on the distribution of chiasmata over chromosomes in a cell were detected. The distribution of chiasmata over chromosomes appeared to be more or less random in both normal and desynaptic plants, which suggests that the ds-1 gene similarly affects chiasma frequencies in all chromosomes. Genetic data reported in the literature indicate that the ds-1 gene affects both the overall chiasma frequency and the chiasma distribution along individual chromosomes rather than chiasma maintenance. Sex differences in chiasma formation were not observed among normal plants or among desynaptic mutants, which indicates that chiasma formation in male and female meiosis of potato is governed by a single control system that is similarly expressed in both sexes.Key words: Solanum, desynapsis, chiasma frequency, male meiosis, female meiosis.

Sex-Specific Recombination Rates in Zebrafish (Danio rerio)

Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 649-657 ◽  
Author(s):  
Amy Singer ◽  
Hodel Perlman ◽  
YiLin Yan ◽  
Charlene Walker ◽  
Graham Corley-Smith ◽  
...  
Keyword(s):  
Genetic Map ◽  
Positional Cloning ◽  
Genetic Recombination ◽  
Physical Distance ◽  
Male Meiosis ◽  
Female Meiosis ◽  
Recombination Rates ◽  
Practical Applications ◽  
Mapping Panel ◽  
Haploid Embryos

Abstract In many organisms, the rate of genetic recombination is not uniform along the length of chromosomes or between sexes. To compare the relative recombination rates during meiosis in male and female zebrafish, we constructed a genetic map based on male meiosis. We developed a meiotic mapping panel of 94 androgenetic haploid embryos that were scored for genetic polymorphisms. The resulting male map was compared to female and sex-average maps. We found that the recombination rate in male meiosis is dramatically suppressed relative to that of female meiosis, especially near the centromere. These findings have practical applications for experimental design. The use of exclusively female meiosis in a positional cloning project maximizes the ratio of genetic map distance to physical distance. Alternatively, the use of exclusively male meiosis to localize a mutation initially to a linkage group or to maintain relationships of linked alleles minimizes recombination, thereby facilitating some types of analysis.

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