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Three approaches to the development of high performance cultivars considering the differing biological background of the starting material

Pank, F.
Acta horticulturae 2002 no.576
Foeniculum vulgare, Hypericum perforatum, Origanum majorana, breeding, cultivars, cytoplasmic male sterility, early development, essential oils, fennel, genotype, heterosis, lipid content, plant breeders
The biological background of medicinal and aromatic plant species varies to a large extent. The following examples demonstrate different breeding approaches with respect to the biological specialties of the breeding objects. Combination breeding by crossing proved to be the appropriate approach to combine the early maturity and the low growth height of a sweet fennel genotype (Foeniculum vulgare Mill. spp. vulgare var. dulce) with the high essential oil content and oil composition of a bitter fennel population (F. vulgare Mill. spp. vulgare var. vulgare) because there were no fertilization barriers between the different parent genotypes. The frequent incidence of cytoplasmic male sterility of sweet marjoram (Origanum majorana L.) favors the development of hybrid varieties with an improved performance due to the hybrid vigor of the F1 of genetically different parent lines with a high homogeneity because the F1 is used as variety for the production. The segregation of following generations prevents unlicensed seed propagation and, in this way, a natural protection of the plant breeders rights is guaranteed. The apomictic behavior of St. John's wort (Hypericum perforatum L.) can be used for fast genetic fixation of desired trait expressions, because seed progenies of high-grade apomicts are true breeding to a great extent. St. John’s wort is in general a pseudogamous facultative apomict, but in rare cases obligatory sexuals and pure apomicts also occur. In a St. John's wort collection of more than 120 accessions the following shares were determined: 94.7% facultative apomicts / sexuals, 2.2% obligatory apomicts, and 2.5% obligatory sexuals.