Intergeneric hybridization in the Rosaceae, subtribe Malinae ( Sun et al., 2018 ), is an important reproductive mechanism that has facilitated plant speciation and domestication of novel plants ( Postman, 2011 ); however, these wide hybridization
Publishers, Hauppauge, NY Tang, F. Wang, H. Chen, S. Chen, F. Liu, Z. Fang, W. 2011 Intergeneric hybridization between Dendranthema nankingense and Tanacetum vulgare Sci. Hort. 132 1 6 Wang, H.C. Yang, J.B. Compton, J.A. Sun, H. 2006 A phylogeny of
without emasculation such as Yang et al. (2010) who conducted intergeneric hybridization without emasculation between Opisthopappus taihangensis (Ling) C. Shih. and Chrysanthemum lavandulifolium (Fisch. ex Trautv.). From our observation in the
The genus Pyrus has been classified into at least 22 primary species. These can be grouped by geographical distribution and/or taxonomic relationships. The European group includes P. communis L., P. nivalis Jacq., and P. cordata, (Desv.) Schneid. The North African group contains P. longipes Coss. and Dur., P. gharbiana Trab., and P. mamorensis Trab. The west Asian group consists of P. syriaca Boiss., P. elaeagrifolia Pall., and P. amygdaliformis Vill., P. salicifolia Pall., P. glabra Boiss., P. regellii Rehd., (syn. P. bucharica and P. heterophylla Reg. & Schmalh). The medium to large fruited east Asian species are P. pyrifolia (Burm.) Nak., P. kansuensis, P. ussuriensis Max., P. hondoensis Kik. and Nak., while the Asian “pea” pear species are P. calleryana Dcne., P. betulaefolia Bung., P.fauriei Schneid., P. dimorphophylla Makino, and P. koehnei Schneid. (3, 27). A number of nonprimary species also appear in the literature, which may be either botanical varieties, subspecies, or interspecific hybrids. Among the east Asian group, P. bretschneideri Rehd. is a probable hybrid of P. betulaefolia and the cultivated forms of P. pyrifolia; P. phaeocarpa Rehd. may be a P. betulaefolia × P. ussurensis hybrid, whereas P. serrulata Rehd. is a probable interspecific hybrid involving P. pyrifolia and P. calleryana.
Four species of Dissotis and three species of Tibouchina, two genera of the Melastomataceae family, were crossed in an attempt to create interspecific and intergeneric hybrids. Intergeneric crosses set seed at a rate of 18.1% and interspecific crosses had a 32.3% rate of seed set. Germination was extremely poor, with only four crosses having germinated seed. Crosses produced 31 seedlings. Three of the seedlings were from intergeneric crosses between Dissotis canescens and Tibouchina lepidota. Interspecific crosses produced 25 seedlings from crosses between Dissotis princeps and Dissotis rotundifolia and three seedlings from crosses between D. canescens and D. princeps. The prognosis for conventional breeding for species in Dissotis and Tibouchina is poor due to low seed set, poor germination, and slow growth of progeny.
Intergeneric hybrids between wingnut (Pterocarya sp.) and walnut (Juglans regia) were developed by regenerating plants from somatic embryos produced on immature cotyledons of seed from control-pollinations. Hybridization was confirmed by isozyme analysis using starch gel electrophoresis. To the best of our knowledge, this is the first report of hybrids between wingnut, which has a high level of resistance to Phytophthora spp. and nematodes, and walnut. Wingnut may now be used as a source of germplasm for improving walnut rootstocks.
Four isozyme systems, glucosephosphate isomerase (PGI, EC 220.127.116.11), phosphoglucomutase (PGM, EC 18.104.22.168), isocitrate dehydrogenase (IDH, EC 22.214.171.124), and malate dehydrogenase (MDH, EC 126.96.36.199), were identified as useful in detecting intergeneric Vitis vinifera × Muscadinia rotundifolia hybrids. Polymorphism between and within the two genera was observed at the PGI-2, PGM-2, and IDH-1 loci. However, the two appeared fixed for different alleles at the MDH-3 locus. The combination of any two of the enzyme systems allowed for rapid identification of F1 hybrids at the young, pre-fruiting seedling stage.
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.
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.