Summary
Attempts at the reciprocal cross between Petunia parodii and P. inflata using standard emasculation and pollination techniques failed. Limited pollen tube growth down the style in reciprocal crosses led to reproductive isolation between the self-compatible P. parodii and self-incompatible P. inflata. The interspecific hybrid was successfully produced by bud-pollination of P. parodii with P. inflata as the male parent in 22 percent of attempts, but not in the opposite direction. In vitro pollination of P. parodii ovaries with P. inflata pollen also produced hybrids. The small size of the ovary made it technically impossible to use P. inflata as the female parent for in vitro pollination. The interspecific hybrids were intermediate, as compared to the two parents, for six of the seven plant and flower characters measured. Furthermore, the hybrids had high pollen fertility, set abundant seed upon self-pollination, and readily inter-crossed with the parental species. The results are consistent with a high degree of chromosomal homology in the parental species and with minor genetic divergency leading to reproductive isolation that is pre-zygotic in nature. Overcoming the barriers to cross-incompatibility by practical techniques resulted in fertile interspecific hybrids that segregated for parental characters. The potential value of employing the parental species in somatic hybridization experiments is discussed.
Similar content being viewed by others
Literature
Anderson, E.; De Winton, D.: The genetic analysis of an unusual relationship between self-sterility and self-fertility in Nicotiana. Anns. Missouri Bot. Garden 18, 97–116 (1931)
Brewbaker, J.L.; Majumder, S.K.: Cultural studies of the pollen population effect and the self-incompatibility inhibition. Amcr. J. Bot. 48, 457–464 (1961)
Frearson, E.M.; Power, J.B.; Cocking, E.C.: The isolation, culture and regeneration of Petunia leaf protoplasts. Dev. Biol. 33, 130–137 (1973)
Fries, R.E.: Die Arten der Gattung Petunia. Kon. Sv. Vet. Akad. Handl. 46, 25–40 (1911)
Grun, P.; Aubertin, M.: The inheritance and expression of unilateral incompatibility in Solanum. Heredity 21, 131–138 (1966)
Hayward, C.; Power, J.B.: Plant production from leaf protoplasts of Petunia parodii. Plant Sci. Letts. 4, 407–410 (1975)
Hogenboom, N.G.: Breaking breeding barriers in Lycopersicon. 4. Breakdown of unilateral incompatibility between L. peruvianum (L.) Mill, and L. esculentum Mill. Euphytica 21, 397–404 (1972)
Knowlton, L.L.; Sink, K.C.: The G locus in Petunia hybrida Vilm.: Negative relationship to endogenous chlorophyll, starch and sugar. Euphytica 26, (1977)
Levin, D.A.: The origin of reproductive isolating mechanisms in flowering plants. Taxon 20, 91–113 (1971)
Linskens, H.F.; Essen, K.: Uber eine spezifische Anfärbung der Pollenschläuche im Griffel und die Zahl der Kallosepfropfen nach Selbstung und Fremdung. 44 10 Naturwissenschaften (1957)
Mather, K.: Specific differences in Petunia. I. Incompatibility. J. Genet. 45, 215–235 (1943)
Mather, K.; Edwardes, P.M.J.: Specific differences in Petunia. III. Flower colour and genetic isolation. J. Genet. 45, 243–260 (1943)
Natarella, N.J.; Sink, K.C.: The morphogenesis of double flowering in Petunia hybrida. Hort. J. Amer. Soc. Hort. Sci. 95, 600–602 (1971)
Natarella, N.J.; Sink, Jr. K.C.: Electrophoretic analysis of protein and peroxidases of selected Petunia species and cultivars. Bot. Gaz. 136, 20–26 (1975)
North, C.: In vitro culture of plant material as an aid to hybridization. Acta Hortic. 63, 67–74 (1976)
Power, J.B. et. al.: Somatic hybridization of Petunia hybrida and P. parodii. Nature 263, 500–502 (1976a)
Power, J.B. et. al.: The isolation, culture and regeneration of leaf protoplasts in the genus Petunia. Plant Sci. Letts 7, 51–55 (1976b)
Rangaswamy, N.S.; Shivanna, K.R.: Induction of gamete compatibility and seed formation in axenic cultures of a diploid self-incompatible species of Petunia. Nature 216, 937–939 (1967)
Rangaswamy, N.S.: Applications of in vitro pollination and in vitro fertilization. In: Plant cell, tissue, and organ culture. Eds. J. Reinert and Y.P.S. Bajaj. Berlin-Heidelberg-New York Springer: (1977)
Sink, Jr., K.C.: The inheritance of apetalous flower type in Petunia hybrida Vilm. and linkage tests with the genes for flower doubleness and grandiflora characters and its use in hybrid seed production. Euphytica 22, 520–526 (1973)
Sink, Jr. K.C.: Inheritance of three genes for morphological characters in Petunia hybrida Vilm. in crosses with four Petunia species. Can. J. Genet, and Cytology 17, 67–74 (1975)
Smith, H.H.: Model systems for somatic cell plant genetics. Bio-Science (May), 269–276 (1974)
Steere, W.C.: Petunia parodii, a new species of the subgenus Pseudenicotiana from Argentina. Papers Mich. Acad. Sci. 13, 213–215 (1930)
Author information
Authors and Affiliations
Additional information
Communicated by H.F. Linskens
Michigan Agricultural Experiment Station Journal Article No. 8404
Rights and permissions
About this article
Cite this article
Sink, K.C., Power, J.B. & Natarella, N.J. The interspecific hybrid Petunia parodii × P. inflata and its relevance to somatic hybridization in the genus Petunia . Theoret. Appl. Genetics 53, 205–208 (1978). https://doi.org/10.1007/BF00277369
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00277369