Interspecific Hybridization of Fragaria vesca subspecies with F. nilgerrensis, F. nubicola, F. pentaphylla, and F. viridis

The potential of using Fragaria vesca L. as a bridge species for interspecific hybridization to F. nilgerrensis Schlect, F. nubicola Lindl., F. pentaphylla Losinsk, and F. viridis Duch. was investigated using a wide germplasm base of 40 F. vesca accessions. This study was successful in producing many hybrids between F. vesca and other diploid species indicating its value as a bridge species. Of the species used as males, F. nubicola, F. pentaphylla, and F. viridis accessions were more successful, averaging 8 to 16 fruit and 16 to 25 seeds/fruit. It was most difficult to obtain hybrids with F. nilgerrensis, which had only three seeds per fruit. Differences among pollen donors were minimal when hybrid seeds were germinated in vitro. For different species combinations, 75% to 99% of seeds had embryos and 77% to 89% of these embryos germinated. The lack of significant differences in crossability variables among the four F. vesca subspecies [i.e., ssp. americana (Porter) Staudt, ssp. bracteata (Heller) Staudt, ssp. vesca L., and ssp. vesca var. semper-florens L.] demonstrated the similarity between these species and the strong potential for gene flow between F. vesca and other diploid species. As European and North American F. vesca subspecies are not sufficiently divergent to differ in interspecific hybridization, F. vesca may be a younger species rather than an older progenitor species.

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Interspecific hybridization between diploid Fagopyrum esculentum and tetraploid F. homotropicum

Canadian Journal of Plant Science ◽

10.4141/p03-147 ◽

2005 ◽

Vol 85 (1) ◽

pp. 41-48 ◽

Cited By ~ 7

Author(s):

Yingjie Wang ◽

Rachael Scarth ◽

Clayton Campbell

Keyword(s):

Interspecific Hybridization ◽

Chromosome Numbers ◽

Dna Analysis ◽

Genetic Recombination ◽

Diploid Species ◽

Normal Growth ◽

Colchicine Treatment ◽

Chromosome Elimination ◽

Ploidy Levels

The wild diploid species Fagopyrum homotropicum (2n = 2x = 16) has been used for buckwheat improvement, but, prior to this study, the tetraploid form (2n = 4x = 32) had not been hybridized with the cultivated species F. esculentum. The objective of this study was to hybridize F. esculentum with tetraploid F. homotropicum to increase the genetic variability. Forty-one interspecific F1 hybrids were obtained through ovule rescue in vitro, with hybridity confirmed using morphological characters, chromosome numbers (2n = 3x = 24) and DNA analysis. The F1 plants were mainly sterile. However, seven seeds were set spontaneously on two hybrid plants, and a large number of seeds were obtained after colchicine treatment. The F2 plants were divided into two groups based on chromosome numbers and morphology. The first group was hexaploid plants (2n = 6x = 48) or hypohexaploid plants (2n = 44–46), partially fertile with “gigas” features including increased height, dark green leaves, and large seeds with thick seed hulls. The second group of plants was diploid (2n = 2x = 16) (one plant had 17 chromosomes), with normal growth and fertility, and a combination of characters from both parents, indicating that genetic recombination had occurred during chromosome elimination. The diploid group was superior to the hexaploid group for use in buckwheat breeding programs due to the desirable characters and the ease of crossing. This is the first report of interspecific hybridization using different ploidy levels in the Fagopyrum genus. Key words: Buckwheat (F. esculentum; F. homotropicum), interspecific hybridization, breeding, tetraploid, diploid, hexaploid, fertility

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Endosperm-based hybridization barriers explain the pattern of gene flow between Arabidopsis lyrata and Arabidopsis arenosa in Central Europe

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1615123114 ◽

2017 ◽

Vol 114 (6) ◽

pp. E1027-E1035 ◽

Cited By ~ 43

Author(s):

Clément Lafon-Placette ◽

Ida M. Johannessen ◽

Karina S. Hornslien ◽

Mohammad F. Ali ◽

Katrine N. Bjerkan ◽

...

Keyword(s):

Gene Flow ◽

Central Europe ◽

Diploid Species ◽

Biological Species ◽

Biological Species Concept ◽

Interspecific Gene Flow ◽

Seed Formation ◽

Arabidopsis Lyrata ◽

Hybrid Seeds ◽

Arabidopsis Arenosa

Based on the biological species concept, two species are considered distinct if reproductive barriers prevent gene flow between them. In Central Europe, the diploid species Arabidopsis lyrata and Arabidopsis arenosa are genetically isolated, thus fitting this concept as “good species.” Nonetheless, interspecific gene flow involving their tetraploid forms has been described. The reasons for this ploidy-dependent reproductive isolation remain unknown. Here, we show that hybridization between diploid A. lyrata and A. arenosa causes mainly inviable seed formation, revealing a strong postzygotic reproductive barrier separating these two species. Although viability of hybrid seeds was impaired in both directions of hybridization, the cause for seed arrest differed. Hybridization of A. lyrata seed parents with A. arenosa pollen donors resulted in failure of endosperm cellularization, whereas the endosperm of reciprocal hybrids cellularized precociously. Endosperm cellularization failure in both hybridization directions is likely causal for the embryo arrest. Importantly, natural tetraploid A. lyrata was able to form viable hybrid seeds with diploid and tetraploid A. arenosa, associated with the reestablishment of normal endosperm cellularization. Conversely, the defects of hybrid seeds between tetraploid A. arenosa and diploid A. lyrata were aggravated. According to these results, we hypothesize that a tetraploidization event in A. lyrata allowed the production of viable hybrid seeds with A. arenosa, enabling gene flow between the two species.

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Interspecific Crossability of Fragaria vesca as a Female Parent

HortScience ◽

10.21273/hortsci.30.4.856d ◽

1995 ◽

Vol 30 (4) ◽

pp. 856D-856

Author(s):

Bob Bors ◽

J. Alan Sullivan

Keyword(s):

Seed Set ◽

Genetic Material ◽

Diploid Species ◽

Female Parent ◽

Fragaria Vesca ◽

Wild Type ◽

The World ◽

Interspecific Crossability ◽

Strawberry Cultivars

Fragaria vesca has been introgressed into F. ×ananassa in the form of decaploids and synthetic octoploids. As F. vesca is self-incompatible and crosses with most diploid Fragaria species when used as a female parent, it could serve as a bridge for introgression of additional genetic material. A primary goal of this study was to screen selections of F. vesca for interspecific crossability among diploid species. The F. vesca collection included 10 cultivars of the alpine strawberry, F. vesca var. semperflorens, as well as 30 wild runnering types gathered from around the world. The following diploid species were represented by one to three genotypes each: F. viridis, F. nubicola, F. nipponica, F. nilgerens, F. iinumae, F. daltoniana, F. gracilis, as well as two unnamed species from China. Fragaria vesca was used as the female parent and the other species provided the pollen. Crossing took place in the greenhouse, with one pollination occurring during the “popcorn” or “balloon” stage. Germination was performed in vitro using cut achenes shortly after fruit ripening. The alpine strawberry cultivars were easier to cross than wild selections of F. vesca. Their continuous blooming habit combined with higher positioning of flowers allowed for easier and perhaps less-damaging emasculation. Crossability, as measured by seed set and germination, was more variable in wild-type F. vesca and generally lower than alpine strawberry cultivars.

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Flowering phenology of Populustremuloides and P. grandidentata and the potential for hybridization

Canadian Journal of Forest Research ◽

10.1139/x80-036 ◽

1980 ◽

Vol 10 (2) ◽

pp. 218-223 ◽

Cited By ~ 3

Author(s):

Kurt S. Pregitzer ◽

Burton V. Barnes

Keyword(s):

Gene Flow ◽

Flowering Time ◽

Seed Production ◽

Flowering Phenology ◽

Hybrid Seed ◽

Hybrid Seed Production ◽

Strong Potential ◽

Hybrid Seeds ◽

Northern Michigan

Flower phenologies of Populustremuloides, P. grandidentata, and P. ×smithii were monitored for 39 clones in southeastern Lower Michigan, U.S.A., and 73 clones in northern Lower Michigan. In southeastern Michigan the two species were generally found to be reproductively isolated where average flowering times were compared. Populustremuloides exhibited greater intra- and interclonal variation than P. grandidentata and flowered for a significantly longer period. However, overlap in flowering times occurred in southeastern Michigan indicating a potential for hybridization and gene flow. Populusgrandidentata female clones pollinated by P. tremuloides males were most likely to produce hybrid seeds. Small, late-developing female catkins of P. tremuloides also showed strong potential for hybrid seed production. Natural F1 hybrids were intermediate in flowering time between the parents. Therefore, phenology is not a complete barrier to natural backcrossing in southeastern Lower Michigan. Little overlap occurred in northern Michigan, thus strongly limiting the potential for hybridization.

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