PRODUCTION OF TETRAPLOID FORMS OF EIGHT TROPICAL LANDSCAPE TREE SPECIES

The prolific production of messy and sometimes hazardous fruits and seeds make the typical 2n forms of many tropical tree species high maintenance and potentially invasive plants.
Tetraploid (4n) plants of monkey pod (Samanea saman), Baker’s shower tree (Cassia bakeriana), golden shower tree (Cassia fistula), pink shower tree (Cassia javanica), dwarf poinciana (Caesalpinia pulcherrima), royal poinciana (Delonix regia), Indian coral tree (Erythrina variegate), and African tulip tree (Spathodea campanulata) were obtained from young diploid (2n) seedlings by a previously developed procedure of using 0.1% colchicine solution to treat shoot meristems of newly germinated seedlings for 48h.
Suspected polyploids, based on leaf thickening, distortion or color intensification, were identified and guard cells were measured.
Many suspected polyploids with guard cells measuring 1.25X or larger than those of the diploid controls were further subjected to chromosome counting, and in one case to flow cytometry analysis to quantify DNA content as a measure of ploidy.
The converted tetraploids along with controls for each species will be field-grown to flowering.
At flowering, 2n and 4n plants will be crossed to produce 3n (triploid) progeny that are expected to be sterile and non-fruiting for lack of regular meiosis and normal gamete production.
Non-fruiting 3n forms of these popular landscape plants (propagated by air layering or grafting) will be less expensive to maintain, will be non-threatening to native ecosystems, and may have slightly larger flowers and bloom over a longer flowering season.

VI International Symposium on New Floricultural Crops

K.W. Leonhardt, X. Shi

colchicine, tetraploid, flow cytometry, invasive species

https://doi.org/10.17660/ActaHortic.2009.813.17