( Lyrene, 2011 ). In our previous study, we have succeeded to obtain several tetraploid shashanbo plants by colchicine treatment (H. Tsuda, unpublished data). The objectives of the present study were as follows: 1) to produce intersectional hybrids from the
to the section Cyanococcus ( Karizumi, 1979 ; Kunitake et al., 2006 ; Luby et al., 1991 ). Therefore, we produced intersectional hybrids between colchicine-induced tetraploid shashanbo and the tetraploid highbush blueberry ‘Spartan’ ( V
. macrocarpon CNJ 09-30-24 on a very modest scale. From 30 pollinations, we produced 599 seeds, and we now have 500+ young and vigorous hybrids ( Table 1 ). This cross was, by our standards, highly successful, for an intersectional cross, producing 20.7 seeds
macrocarpon (Ehlenfeldt et al., in preparation). Several salient points can be made regarding the crosses reported here: Despite being intersectional crosses, it was possible to generate hybrids with 4 x V. meridionale with relative ease, and hybrids
three salient points to be made about these hybrids: 1) Despite being intersectional crosses, it was possible to generate hybrids of V. corymbosum with V. meridionale , using V. corymbosum as females. These hybrids were relatively easy to make and
Abstract
The intersectional hybrids, Oncidium altissimum × O. sarcodes and O. floridanum × maculatum, and the intergeneric hybrid, Odontoglossum stenoglossum × O. macuiatum (all with 2n = 56), showed near normal meiosis with 27 or 28 bivalents per pollen mother cell indicating strong homology of parental genomes. Trichocentrum albopurpureum (2n = 24) × O. lanceanum (2n = 26) exhibited fair homology of parental genomes with the formation of 6 to 10 bivalents out of the possible 12. The other intersectional hybrids, O. pulvinatum (2n = 42) × O. floridanum (2n = 56), O. triquetrum (2n = 42) × O. floridanum (2n = 56), O. microchilum (2n = 36) × O. floridanum (2n = 56) and O. microchilum (2n = 36) × O. onustum (2n = 56) and the intergeneric hybrid, Comparettia falcata (2n = 42) × O. onustum (2n = 56) showed highly irregular meiotic behavior with poor chromosome pairing. The number of bivalents in these hybrids ranged from 1.4 to 9.5, indicating poor genome relationships of the parental species.
). Most hybrids between diploid and tetraploid Vaccinium species are tetraploid, due to the production of functioning 2 n gametes by the diploid ( Galletta, 1975 ). With so many species and sections, the number of potential intersectional cross
Darrow and Camp (1945) who reported the cross V. australe (= V. corymbosum ) × V. arctostaphylos . They did not however subsequently report that any hybrids or advanced selections resulted. Ballington (2000) reported several intersectional crosses
Buddleja indica Lam. is encountered frequently as a houseplant or a conservatory specimen and is attractive ornamentally for its oak-shaped foliage. Buddleja indica, a tetraploid African species, 2n = 76, was crossed to the Asiatic tetraploid species B. davidii Franch. The F1 generation was intermediate in foliage character between the two parents. Flowers of the F1 were either white or light lavender in color and the number of flowers per inflorescence was intermediate between the parents. The F1 plants were fertile. These hybrids might be suitable for greenhouse or container culture due to their attractive foliage and floral display.
types. Intersectional hybrids are crosses between the two groups. Intersectionals (Itohs) have a similar growth pattern to herbaceous peonies, so they are able to withstand temperatures that would kill tree peonies, but their foliage and the flowers have