ornamentals mentioned previously. Santonia ‘Golden Light’, an intergeneric hybrid cultivar of S . aurantiaca × L . modesta , has already been developed through ovule culture ( Clark et al., 2005 ; Eason et al., 2001 ; Morgan et al., 2001 , 2003 ). This
Junji Amano, Sachiko Kuwayama, Yoko Mizuta, Masaru Nakano, Toshinari Godo and Hajime Okuno
Sandra M. Reed, Keri D. Jones and Timothy A. Rinehart
their intergeneric hybrids from a principal-coordinate analysis based on data from eight SSR loci. Symbols for hybrid progeny are shaded the same as their H. macrophylla parent. As expected, hybrid populations show considerable genetic diversity and
Darren Touchell, Zenaida Viloria and Thomas Ranney
Weigela Thunb. consists of 12 species distributed throughout Northeast Asia. Diervilla Mill. is a closely related genus containing three species endemic to North America. Taxa from both of these genera are important nursery crops. Hybrids between these genera could potentially combine the excellent cold hardiness and adaptability of Diervilla with diverse forms, foliage colors, and flower colors found in Weigela. Prior attempts to create intergeneric hybrids between these genera were unsuccessful and resulted in embryo abortion before seeds matured. To overcome this barrier, ovule culture and micropropagation procedures were used to develop intergeneric hybrids. Cleaved amplified polymorphic sequences (CAPS) analysis was used to verify hybrids. Intergeneric crosses, D. lonicera × W. middendorfiana, D. sessilifolia × W. florida (two clones), and D. lonicera × W. florida were attempted. Crosses of D. lonicera × W. middendorfiana did not produce viable hybrids. From the remaining three crosses, a total of 544 plants were obtained from 1278 ovules. About 85% of the 544 plants appeared very chlorotic or had low vigor, and senesced when transferred to multiplication medium. Only 80 of the 544 plants were successfully maintained in tissue culture, of which 10 have been successfully transferred ex vitro. CAPS analysis indicated that a majority of these plants were hybrids. Further studies are focused on improving tissue culture procedures and other methods to develop tetraploids to increase plantlet vigor and fertility.
Jianhua Li, Suzanne Shoup, Jianhua Li and Thomas S. Elias
Intergeneric hybrids are generally rare; nevertheless, such putative hybrids need confirmation from other lines of evidence besides morphological intermediacy. In this study the authors used DNA sequences of nuclear and chloroplast genes to determine the hybrid identity of ×Chitalpa. Their results confirm that both ×Chitalpa tashkentensis `Pink Dawn' and ×C. tashkentensis `Morning Cloud' are the result of an Chilopsis linearis ×Catalpa sp. cross. However, Catalpa bignonioides does not seem to have participated in the cross, as speculated before. Different species of Catalpa may have been used as the paternal parent. ×C. tashkentensis `Morning Cloud' is the result of the C. linearis × C. speciosa cross, whereas the paternal parent of ×C. tashkentensis `Pink Dawn' may be a hybrid plant of C. ovata and C. speciosa.
Malcolm W. Smith, Debra L. Gultzow and Toni K. Newman
“intergeneric” hybrids involving Poncirus Raf., Microcitrus Swing., Eremocitrus Swing., Fortunella Swing., and Citrus (e.g., Barrett, 1977 ; Hutchison, 1976 ; Iwamasa et al., 1985 , 1988 ) would constitute only “interspecific” hybrids under a more
Gabriela Verdugo Ramírez, Mauricio Cisternas Baez, Ursula Steinfort, Hermine Vogel and Rosa Cueto-Ewoldt
Chilean species. One of the most important outcomes of these breeding projects was the development of the first intergeneric hybrid, Chlorogavilea ‘Máxima’ obtained from Chloraea crispa Lindl., and Gavilea longibracteata (Lindl.) Sparre ex Navas
Thomas G. Ranney and Paul R. Fantz
Franklinia alatamaha Bartr. ex Marshall represents a monotypic genus that was originally discovered in Georgia, USA, but is now considered extinct in the wild and is maintained only in cultivation. Although Franklinia is very ornamental, with showy flowers and crimson/maroon fall foliage, it tends to be short lived when grown as a landscape tree and is known to be susceptible to a variety of root pathogens. Gordonia lasianthus (L.) Ellis is an evergreen tree native to the southeastern United States, typically growing in riparian habitats. Gordonia lasianthus has attractive foliage and large, white, showy flowers, but limited cold hardiness. Hybridization between F. alatamaha and G. lasianthus could potentially combine the cold hardiness of F. alatamaha with the evergreen foliage of G. lasianthus and broaden the genetic base for further breeding and improvement among these genera. Controlled crosses between F. alatamaha and G. lasianthus resulted in intergeneric hybrid progeny. A morphological comparison of parents and the progeny is presented. ×Gordlinia grandiflora Ranney and Fantz (mountain gordlinia) is proposed as the name for these hybrids and is validated with a Latin diagnosis.
Thomas G. Ranney, Thomas A. Eaker, Paul R. Fantz and Clifford R. Parks
Franklinia alatamaha Bartr. ex Marshall represents a monotypic genus that was originally discovered in Georgia, but is now considered extinct in the wild and is maintained only in cultivation. Although Franklinia is very ornamental, with showy flowers and crimson/maroon fall foliage color, it tends to be short lived when grown as a landscape tree and is known to be susceptible to a variety of root pathogens. Schima argentea Pritz is an evergreen tree that is native to Asia and is valued for its glossy foliage, late-summer flowers, and broad adaptability in mild climates. Hybridization between these genera could potentially combine the cold hardiness and desirable ornamental characteristics of F. alatamaha with the greater adaptability, utility, and genetic diversity of S. argentea. Controlled crosses between F. alatamaha and S. argentea resulted in new intergeneric hybrid progeny. A morphological comparison of parents and the progeny is presented. ×Schimlinia floribunda Ranney and Fantz (mountain schimlinia) is proposed as the name for these hybrids and is validated with a Latin diagnosis.