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

Abstract

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

Interspecific hybridization of Fragaria moschata with two diploid species, F. nubicola and F. viridis

“…Descriptions of the first four characters are contained in Bors and Sullivan (2005). Ploidy levels of hybrids that bloomed after one year were confirmed with flow cytometry (Bors, 2000).…”

“…While many combinations of accessions did not create viable offspring, most available germplasm was successfully incorporated into at least one tetraploid. Having a wide genetic base is especially important for interspecific crosses (Bors & Sullivan, 2005;Hermsen, 1992). To increase success of wide crosses, using many parental genotypes for a few interspecific hybrids is superior to using a few parents for many crosses (Galletta & Maas, 1990).…”

“…Fragaria nubicola and F. viridis accessions are hermaphroditic and were used as both male and female parents. Seeds were germinated in vitro using the technique of Miller et al (1992) with slight modifications described in Bors and Sullivan (2005). Briefly, only 30% (rather than 50%) of each achene was removed and only white healthy embryos were placed on media for germination.…”

“…It appears that F. viridis and F. nubicola have the greatest potential to produce fertile hybrids with F. moschata. Studies of interspecific hybridization with other diploid Fragaria species have shown that using more accessions can increase the frequency of successful hybrids (Bors & Sullivan, 2005;Hermsen, 1992).…”

Diversity of metabolite patterns and sensory characters in wild and cultivated strawberries1

“…Later, since the beginning of the 20th century F. vesca was used in breeding programs with F. × ananassa as donor for interesting sensory and resistance traits [2,10,13]. The development of synthetic octoploids [4,7] was also based on F. vesca accessions.…”