Upgrading the genetic quality of hardwoods by selection of elite germplasm and conservation on marginal and abandoned farmland
The following numbers of elite trees were identified and mapped for foresters: Prunus 170, Quercus 125, Castanea 90, Juglans I 10, Fraxinus 80, Acer 300, Camellia 200, Alnus 40, Ulmus 20, Populus 20, Tilia 10. Scions were collected and grafted as well as other propagules from elite trees or seed sources. Elite germplasm were widely exchanged among partners. Methods for sterilization of buds and other explants were found. Several phase-related phenomena were studied. Aged tissues showed poorer shoot proliferation and rooting ability. Several treatments seemed to lessen the maturity effects, but a complete phase reversal from maturity to juvenility was not achieved. Micropropagation was achieved for all species using juvenile sources of buds. Biochemical markers were found which characterized rooting capacity, propagation rate maturity status and adverse physiological disorders such as vitrification. The total production was 130,000 plants of Prunus, 67,000 Camellia, 42,000 Castanea and 1 to 10,000 each for the remaining species. The industrial partners adopted the research methodologies to micropropagate and wean large numbers of plants for which they had a market outlet and research interest. Over 100 cultures per clone were actively propagated of Prunus, Tilia, Syringa, Quercus, Betula, Castanea and Camellia. Attempts to automate production of Quercus, using systems of either a tidal delivery or liquid replenishment, were evaluated; they require further development for industrial application. An analysis of production costs by 3 industrial partners showed variation between countries, but in most cases the labour accounted for over 50% of total costs. The cost of plants was generally higher (but not always) by micropropagation when compared to the market price for equivalent seedlings. The locations of elite trees in forests was documented, and many clones of each species were established and conserved in the nursery, mainly by grafting. Shoot clusters were also successfully stored in vitro and reactivated for periods of 11 to 48 months Quercus, 3 to 12 months Castanea and 12 months Camellia.