scholarly journals The origin of polyploids via 2n gametes in Vaccinium section Cyanococcus

Euphytica ◽  
1991 ◽  
Vol 61 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Rodomiro Ortiz ◽  
Leo P. Bruederle ◽  
Timothy Laverty ◽  
Nicholi Vorsa
Keyword(s):  
2N Gametes ◽  
Origin Of Polyploids ◽  
Vaccinium Section Cyanococcus

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.

2n Gametes for True Seed Production (TPS) in Potato: Basic and Applied Aspects

1992 ◽  
pp. 274-278
Author(s):  
Luigi Frusciante ◽  
Amalia Barone ◽  
Donatella Consoli ◽  
Clara Conicella ◽  
Luigi M. Monti
Keyword(s):  
Seed Production ◽  
2N Gametes ◽  
True Seed

Potato germplasm enhancement with disomic tetraploid Solanum acaule. I. Efficiency of introgression

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Kazuo Watanabe ◽  
Carlos Arbizu ◽  
P. E. Schmiediche
Keyword(s):  
Efficient Method ◽  
Wild Species ◽  
Egg Production ◽  
Chromosome Doubling ◽  
Embryo Rescue ◽  
Germplasm Collection ◽  
2N Gametes ◽  
Germplasm Enhancement ◽  
Technical Problems ◽  
Solanum Acaule

The wild potato species Solanum acaule (acl) was used as a model of a disomic tetraploid Solanum species to develop systematic methods of germplasm enhancement for disomic tetraploid species. The objective was to develop a genetically efficient method to overcome the inherent technical problems encountered in the utilization of disomic tetraploid wild species. Accessions of acl were selected from CIP's wild germplasm collection and from the collection of University of Birmingham, with emphasis on genetic attributes such as PLRV resistance and (or) PSTV resistance. Four methods were tested: (i) triploids from crosses between 4x acl × 2x potato were selected for 2n gametes production and were crossed to tetraploids or to diploids with 2n egg production; (ii) axillary buds of triploid hybrids were treated with colchicine to double chromosome numbers to generate hexaploids; (iii) in vitro chromosome doubling to obtain hexaploids from triploid hybrids; and furthermore (iv) the selected acl clones were directly crossed to tetraploid potatoes followed by a combination of second compatible pollinations with IvP 35 and subsequent embryo rescue. The combination of second compatible pollination and embryo rescue was found to be the most genetically efficient method for the utilization of the valuable genetic attributes of acl.Key words: inter-EBN crosses, ploidy manipulation, polyploid, potato breeding, wild species

Morphological Comparisons and Hypotheses on the Origin of Polyploids in Parthenogenetic Fasciola sp.

2000 ◽  
Vol 86 (4) ◽  
pp. 724 ◽  
Author(s):  
Kunio Terasaki ◽  
Yasutaka Noda ◽  
Toshiyuki Shibahara ◽  
Tadashi Itagaki
Keyword(s):  
Origin Of Polyploids

Analysis of genetic composition and transmitted parental heterozygosity of natural 2n gametes in Populus tomentosa based on SSR markers

Planta ◽  
2018 ◽  
Vol 247 (6) ◽  
pp. 1407-1421 ◽  
Author(s):  
Zhiqiang Han ◽  
Xining Geng ◽  
Kang Du ◽  
Congping Xu ◽  
Pengqiang Yao ◽  
...  
Keyword(s):  
Ssr Markers ◽  
2N Gametes ◽  
Populus Tomentosa ◽  
Genetic Composition

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.

2n gametes in Solanum commersonii and cytological mechanisms of triplandroid formation in triploid hybrids of Solanum commersonii × Solanum gourlayi

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 864-869 ◽  
Author(s):  
R. W. Masuelli ◽  
E. L. Camadro ◽  
A. O. Mendiburu
Keyword(s):  
2N Gametes ◽  
Pollen Grains ◽  
Solanum Commersonii ◽  
Stainable Pollen ◽  
Large Size ◽  
Common Potato ◽  
Aneuploid Chromosome ◽  
The Common ◽  
Bridge Species ◽  
Solanum Gourlayi

Solanum commersonii Dun. (cmm) is a diploid wild species of potential value for potato breeding. Ploidy level manipulations are necessary to cross this species with the common potato. This could be achieved by the use of "bridge" species and sexual polyploidization in which 2n gametes are involved. Eight introductions of cmm were screened for production of (i) diplandroids, through cytological observations confirmed by controlled 4x Solanum acaule Bitt. (acl) × 2x cmm crosses, and (ii) diplogynoids, by controlled 2x cmm × 2x Solanum gourlayi Haw. (grl) crosses. Eleven plants produced 1–3% large size pollen and one plant produced more than 3% of this type of pollen. Twelve triploid and seven tetraploid hybrids were obtained when these plants were used in crosses with acl. On the other hand, 75 triploid hybrids were obtained from the second type of cross. The average pollen stainability in the diplogynoid triploid cmm × grl hybrids was 18.9%, with a range of 2–34.4%. Forty-four to 54.6% of meiocytes with parallel spindles in metaphase II and anaphase II were observed in microsporogenesis of these hybrids. For each clone, the frequency of triplandroids predicted according to the frequency of meiocytes with parallel, fused and tripolar spindles in anaphase II were 52.3, 36.6, and 45.2%, respectively. These values were highly superior to the frequency of triplandroids predicted according to the number of dyads and triads observed, 8.8, 0.7, and 3.9%, respectively. However, triplandroid frequencies predicted according to the frequencies of fused and tripolar spindles agree with the triplandroid frequencies observed. The frequencies of stainable pollen grains are not completely accounted for by the formation of fused and tripolar spindles. In view of the variability encountered in size, it is assumed that a high proportion of gametophytes with aneuploid chromosome numbers are also stainable. A hypothesis is put forward regarding the possible genetic control of triplandroid formation in the diplogynous triploid hybrids analyzed.Key words: 2n gametes, triploid hybrids, spindle orientation, Solanum commersonii Dun.

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