Using disomic 4x(2EBN) potato species' germplasm via bridge species Solanum commersonii

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 866-870 ◽  
Author(s):  
J. B. Bamberg ◽  
R. E. Hanneman Jr. ◽  
J. P. Palta ◽  
J. F. Harbage
Keyword(s):  
Solanum Tuberosum ◽  
Inbreeding Depression ◽  
Chromosome Pairing ◽  
Chromosome Doubling ◽  
Embryo Rescue ◽  
Diploid Species ◽  
2N Gametes ◽  
Solanum Commersonii ◽  
Potato Germplasm ◽  
Bridge Species

The cultivated potato Solanum tuberosum Dunal has many wild related species with desirable traits. Some of these wild tetraploids have disomic chromosome pairing, ready selfing with little inbreeding depression, but have strong crossing barriers with cultivars. They hybridize most easily with 2EBN forms (which include most diploid species). Chromosome doubling to the 8x level, use of 2n gametes, use of 2n gametes of 4x–2x triploid hybrids, and embryo rescue have been proposed to overcome the crossability barrier of these species with S. tuberosum. In this study, 2x S. commersonii (cmm) was used as a bridge species with S. acaule and series Longipedicellata species. Synthetic tetraploid 4x-cmm crossed readily to disomic 4x species, resulting in fertile F1 and F2 hybrids. Some of these had 2n gametes, which enabled direct crossing to tuberosum, resulting in 6x hybrids. The benefits of this scheme are (i) hybrids are relatively fertile, so many progeny may be produced for selection at each step, (ii) hybridization with cmm results in 2n gametes needed for crossing to tuberosum, and breaks up restricted recombination within disomic genomes, and (iii) simple techniques and tools are employed.Key words: Solanum, potato, germplasm, crossability.

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

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.

scholarly journals Pathways for Introgression of Pest Resistance into Arachis hypogaea L.1

1991 ◽  
Vol 18 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Charles E. Simpson
Keyword(s):  
Arachis Hypogaea ◽  
Chromosome Doubling ◽  
Diploid Species ◽  
Gene Introgression ◽  
Diploid Hybrid ◽  
B Genome ◽  
Arachis Hypogaea L ◽  
A Genome ◽  
Bridge Species ◽  
Species Hybrids

Abstract Four pathways for gene introgression into Arachis hypogaea L. were studied. Two “hexaploid routes” involved direct crosses of diploid Arachis species and diploid species hybrids with A. hypogaea (Pathways 1 and 2, respectively) and were followed by chromosome doubling with colchicine. A third pathway, a tetraploid route, involved chromosome doubling of a diploid hybrid before crossing with A. hypogaea. These first three routes involved only the A genome species, and all were unsuccessful because of lack of fertility. The fourth pathway, also a tetraploid route, utilized the B genome A. batizocoi Krap. et Greg. as a bridge species and brought about a successful (fertile) introgression. Genes from A. cardenasii Krap. et Greg. nom. nud. and A. chacoensis Krap et Greg. nom. nud. were combined into a hybrid and incorporated into A. hypogaea by using the B genome bridge species. Introgression of additional characters from these and other species through this pathway should be possible.

CHROMOSOME RELATIONSHIPS BETWEEN THE CULTIVATED OAT AVENA SATIVA (6x) AND A. VENTRICOSA (2x)

1970 ◽  
Vol 12 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Hugh Thomas
Keyword(s):  
Chromosome Pairing ◽  
Avena Sativa ◽  
Diploid Species ◽  
Meiotic Behaviour ◽  
Hexaploid Species ◽  
C Genome

Chromosome pairing in the F1 hybrid between the cultivated oat Avena sativa and a diploid species A. ventricosa, and in the derived amphiploid, shows that the diploid species is related to one of the genomes of the hexaploid species. The amount of chromosome pairing observed in complex interamphiploid hybrids demonstrates further that A. ventricosa is related to the C. genome of A. sativa. However, the chromosomes of the diploid species have become differentiated from that of the C genome of A. sativa and this is readily apparent in the meiotic behaviour of both the F1 hybrid and the amphiploid.

scholarly journals Relations and evolution in Cheilanthes (Sinopteridaceae, Pteridophita) in Macaronesia and Mediterranean area, deduced from genome analysis of their hybrids

1983 ◽  
Vol 8 ◽  
pp. 101-126 ◽  
Author(s):  
G. Vida ◽  
A. Major ◽  
T. Reichstein
Keyword(s):  
Chromosome Number ◽  
Genome Analysis ◽  
Chromosome Doubling ◽  
Diploid Species ◽  
Mediterranean Area ◽  
Basic Chromosome Number ◽  
The Other ◽  
Experimental Conditions ◽  
Natural Group ◽  
Basic Chromosome

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.

Genomic in situ hybridization analysis of a trigenomic hybrid involving Solanum and Lycopersicon species

Genome ◽  
2001 ◽  
Vol 44 (2) ◽  
pp. 299-304 ◽  
Author(s):  
S N Haider Ali ◽  
Dirk Jan Huigen ◽  
M S Ramanna ◽  
Evert Jacobsen ◽  
Richard GF Visser
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Doubling ◽  
Genomic In Situ Hybridization ◽  
Potato Genome ◽  
Meiotic Chromosomes ◽  
Lycopersicon Species ◽  
Bridge Species ◽  
Genomic Probes ◽  
Homoeologous Chromosomes

A 4x potato (+) tomato fusion hybrid (2n = 4x = 48) was successfully backcrossed with a diploid Lycopersicon pennellii (2n = 2x = 24). Genomic in situ hybridization (GISH) on somatic and meiotic chromosomes confirmed that the progenies were triploids (2n = 3x = 36) and possessed three different genomes: potato, tomato, and L. pennellii. Therefore, they have been called trigenomic hybrids. Total genomic probes of both Lycopersicon species were found to hybridize mutually, whereas the potato genome was clearly differentiated. During metaphase I, bivalents were formed predominantly between tomato and L. pennellii chromosomes and the univalents of potato chromosomes were most common. Trivalents in all cases included homoeologous chromosomes of potato, tomato, and L. pennellii. However, the triploids were totally sterile as determined from extensive crossing. On chromosome doubling of triploids by shoot regeneration from callus, hexaploids (2n = 6x = 72) were obtained. Despite exhibiting clear allohexaploid behaviour by forming 36 bivalents at meiosis, these were also completely sterile like their triploid counterparts. In spite of this drawback, the prospects of chromosome pairing between potato L. pennellii and Solanum genomes does open the possibilities for bringing the two genera close.Key words: trigenomic triploids, GISH, bridge species, potato (+) tomato fusion hybrids.

Chromosome pairing and potential for intergeneric recombination in some hypotetraploid somatic hybrids of Lycopersicon esculentum (+) Solanum tuberosum

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1032-1041 ◽  
Author(s):  
J. H. de Jong ◽  
A. M. A. Wolters ◽  
J. M. Kok ◽  
H. Verhaar ◽  
J. van Eden
Keyword(s):  
Solanum Tuberosum ◽  
Lycopersicon Esculentum ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Somatic Hybrids ◽  
Cytogenetic Study ◽  
Unreduced Gametes ◽  
Root Tip ◽  
Prophase I ◽  
Metaphase I

Three somatic hybrids resulting from protoplast fusions of a diploid kanamycin-resistant line of tomato (Lycopersicon esculentum) and a dihaploid hygromycin-resistant transformant of a monohaploid potato (Solanum tuberosum) line were used for a cytogenetic study on chromosome pairing and meiotic recombination. Chromosome counts in root-tip meristem cells revealed two hypotetraploids with chromosome complements of 2n = 46 and one with 2n = 47. Electron microscope analyses of synaptonemal complex spreads of hypotonically burst protoplasts at mid prophase I showed abundant exchanges of pairing partners in multivalents involving as many as eight chromosomes. In the cells at late pachytene recombination nodules were found in multivalents on both sides of pairing partner exchanges, indicating recombination at both homologous and homoeologous sites. Light microscope observations of pollen mother cells at late diakinesis and metaphase I also revealed multivalents, though their occurrence in low frequencies betrays the reduction of multivalent number and complexity. Precocious separation of half bivalents at metaphase I and lagging of univalents at anaphase I were observed frequently. Bridges, which may result from an apparent inversion loop found in the synaptonemal complexes of a mid prophase I nucleus, were also quite common at anaphase I, though the expected accompanying fragments could be detected in only a few cells. Most striking were the high frequencies of first division restitution in preparations at metaphase II/anaphase II, giving rise to unreduced gametes. In spite of the expected high numbers of balanced haploid and diploid gametes, male fertility, as revealed by pollen staining, was found to be negligible.Key words: synaptonemal complex, recombination, chromosome pairing, somatic hybrid, Lycopersicon esculentum (+) Solanum tuberosum.

Overcoming crossing barriers between nontuber-bearing and tuber-bearing Solanum species: towards potato germplasm enhancement with a broad spectrum of solanaceous genetic resources

Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 27-35 ◽  
Author(s):  
K. N. Watanabe ◽  
M. Orrillo ◽  
S. Vega ◽  
J. P. T. Valkonen ◽  
E. Pehu ◽  
...  
Keyword(s):  
Wild Species ◽  
Embryo Rescue ◽  
Leaf Roll ◽  
Reproductive Traits ◽  
Solanum Species ◽  
Interspecific Crosses ◽  
Potato Leaf ◽  
Germplasm Enhancement ◽  
Breeding Lines ◽  
Potato Germplasm

The first direct sexual hybrids between diploid nontuber-bearing species and diploid potato breeding lines are reported here. Three nontuberous species of Solanum, S. brevidens, S. etuberosum, and S. fernandezianum, were used for sexual crosses, achieved by a combination of rescue pollinations and embryo rescue. Initial hybrid selection was made using an embryo spot marker, followed by the evaluation of morphological and reproductive traits. Putative hybrids were first tested for resistance to potato leaf roll virus derived from the wild species, and then were tested with molecular markers using species-specific DNA probes. Finally, the tuberization of several 2x hybrids was tested for actual potato germplasm enhancement. These hybrids are unique in terms of their potential to enhance recombination between chromosomes of wild species and those of cultivated potatoes in germplasm utilization, and to exploit the genetic nature of tuber formation. The finding that nontuber-bearing Solanum spp. can be directly crossed with tuber-bearing species also has important implications for the regulatory aspects of the use of genetically modified organisms.Key words: nontuber-bearing Solanum, potato germplasm enhancement, interspecific crosses, chromosome manipulation, inter-EBN crosses, diploid.

Evidence for genetic suppression of heterogenetic chromosome pairing in polyploidy species of Solanum, sect. Petota

1983 ◽  
Vol 25 (5) ◽  
pp. 530-539 ◽  
Author(s):  
Jan Dvořák
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Diploid Species ◽  
Diploid Hybrid ◽  
Polyploid Species ◽  
Chromosome Differentiation ◽  
Genetic Suppression ◽  
Solanum Sect ◽  
Paradoxical Results

Data on chromosome pairing in haploids and interspecific hybrids of Solanum, sect. Petota reported in the literature were used to determine whether the diploidlike chromosome pairing that occurs in some of the polyploid species of the section is regulated by the genotype or brought about by some other mechanism. The following trends emerged from these data. Most of the polyploid × polyploid hybrids had high numbers of univalents, which seemed to indicate that the polyploid species were constructed from diverse genomes. Haploids, except for those derived from S. tuberosum, had incomplete chromosome pairing. All hybrids from diploid × diploid crosses had more or less regular chromosome pairing, which suggested that all investigated diploid species have the same genome. Likewise, hybrids from polyploid × diploid crosses had high levels of chromosome pairing. These paradoxical results are best explained if it is assumed that (i) the genotypes of most polyploid species, but not those of the diploid species, suppress heterogenetic pairing, (ii) that nonstructural chromosome differentiation is present among the genomes of both diploid and polyploid species, and (iii) the presence of the genome of a diploid species in a polyploid × diploid hybrid results in promotion of heterogenetic pairing. It is, therefore, concluded that heterogenetic pairing in most of the polyploid species is genetically suppressed.

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