IUFRO Breeding theory and progeny testing

The forested area of Greece represents the 20% of the total land area of the country, while 40% of the existing forests are formed by coniferous species. Pinus halepensis Mill. and Pinus brutia Ten. (species of the group Halepensis) are valuable and prominent low elevation Mediterranean pines with a significant role to rural economies. Both species’ ability to grow in the adverse climatic conditions of the Mediterranean region, their fast growth in favorable sites together with the ability to endure forest fires through specific mechanisms, render them irreplaceable multipurpose species for forestry in the special and delicate Mediterranean ecosystem.

Breeding efforts for P. halepensis and P. brutia were initiated two decades ago aiming to selection of plus trees, establishment of a network of provenance-progeny tests and a P. halepensis seed orchard. Remarkable differences were recorded on a population level for both species, as the most volume productive provenances yielded up to a 17- 20% increase above average volume growth. The strong additive genetic control for growth traits exhibited by specific populations of both species, coupled with the marked differences among families for their growth performance, suggested high potential for selection. Genetic gain was as high as 6.5%, depending upon selection method.

Pinus nigra Arn. is a high elevation (above 600m) pine of great economic importance due to its timber quality. Thus, three clonal seed orchards were established that cover the demand for genetically improved planting stock in the northern, central and southern part of the country. Orchards’ roguing is planned as soon as progeny testing of clones yields reliable results.

Cupressus sempervirens L. breeding efforts have mainly focused towards resistance to the fungus Seiridium cardinale (Wagener) Sutton & Gibson. Three provenance-progeny tests, two clonal tests of resistant material and a seed orchard for the production of resistant to cancer genetic material have been put in place.

Results point towards an urgent necessity to take further steps for the genetic improvement of the Mediterranean conifers, given their great potential, in order to secure substantially better growth combined with adaptation to future environmental changes.

Author: Evi Alizoti, Aristotle University of Thessaloniki, School of Forestry and Natural Environment Laboratory of Forest Genetics and Tree Improvement, 54124 Thessaloniki, Greece.