Interspecific hybridisation between Pelargonium zonale hybrids and Pelargonium tongaense Vorster on the tetraploid ploidy level
2012
Esenalieva, A. | Drewes-Alvarez, R. | Arnold, R. | Pohlheim, F. | Wiedemann, M. | Meinl, K. | Hofmann, C. | Olbricht, K.
Funnel effects in breeding programmes of Pelargonium zonale hybrids are obvious after more than 200 years of breeding history although several species are expected to be ancestors of this most important bedding plant. Introgression of wild species is valuable for widening the gene pool and to increase diversity in plant characteristics. Pelargonium tongaense Vorster was discovered in 1983 in the northeast region of Natal, South Africa. This species belongs to the section Ciconium like the two main ancestors of the P. zonale hybrids P. zonale (L.) L’Hérit. and P. inquinans (L.) L’Hérit. In our experiments, the chromosome number of P. tongaense was doubled by mutagenesis (colchicine) from 2n=2x=18 to 2n=4x=36. Subsequent cross-combination with Pelargonium zonale hybrids resulted in fertile F1 plants. Self-pollination and backcrosses with cultivars up to the F3 are reached so far. Strong root growth enables these clone selections to grow very efficient and drought tolerant as plants in the open planting in urban areas. The trailing character perfectly suits with requirements for baskets. Parallel cross-combination on the species levels showed heterosis effects. In addition, chlorophyll deficiencies could be observed.
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