THE IMPORTANCE OF CLONAL SEED ORCHARDS IN SEED PRODUCTION AND CONSERVATION OF FOREST GENETIC RESOURCES IN CROATIA

Sukladno razdjelbi šuma u Hrvatskoj na ekogeografske sjemenske regije i zone osnovane su tri proizvodne klonske sjemenske plantaže hrasta lužnjaka (Quercus robur L.), dvije poljskog jasena (Fraxinus angustifolia Vahl) te po jedna plantaža hrasta kitnjaka (Quercus petraea (Matt.) Liebl.), divlje trešnje (Prunus avium L.) i crnog bora (Pinus nigra J. F. Arnold). Fenotipska selekcija i heterovegetativno razmnožavanje plus stabala te osnivanje klonskih sjemenskih plantaža započeto je radi ostvarenja učestalijeg uroda uroda i dobivanja genetski kvalitetnoga šumskog sjemena u kategorijama „kvalificiran“ i „testiran“. U njima se redovito provode pomotehnički zahvati, zaštita i druge mjere za održavanje sjemenskog objekta. Započeta je i procjena genetske vrijednosti majčinskih stabala u testovima potomstva i selekcija po genotipu radi povećanja stvarenja genetske dobiti. U trima plantažama hrasta lužnjaka (Quercus robur L.) provedene su analize genetske varijabilnosti pomoću jezgrinih i kloroplastnih mikrosatelitskih biljega. Istovremeno se provodi i očuvanje genetske raznolikosti naših vrsta šumskog drveća statičkom metodom ex situ. Klonske sjemenske plantaže čine jezgru očuvanja genofonda, jer je odnos između veličine populacije i postotka očuvane heterozigotnosti tako sveden na minimalan gubitak ukupne aditivne genetske varija bilnosti. Klimatske promjene i novi stanični uvjeti stvorit će dodatne izazove u sjemenarstvu i gospodarenju šumama s posljedicama utjecaja na njihovu ekonomsku i socijalnu korist te na biološku raznolikost šumskih ekosustava.In accordance with the division of forests in Croatia into cogeographic seed regions and zones, the following productive clonal seed orchards have been established: three orchards of pedunculate oak (Quercus robur L.), two of narrow-leaved ash (Fraxinus angustifolia Vahl), one of sessile oak (Quercus petraea (Matt.) Liebl,), one of wild cherry (Prunus avium L.) and one orchard of black pine (Pinus nigra J. F. Arnold). Phenotypical selection and heterovegetative propagation of plus trees, as well as the establishment of clonal seed orchards were launched with the goal of controlling more regular yield periodicity and obtaining forest seed of good genetic quality in the categories Qualified and Tested. The orchards are regularly subjected to pomotechnical treatments, protection and other measures of seed site maintenance. The evaluation of genetic values of mother trees in progeny tests and selection by genotype were also started for the purpose of obtaining increased genetic gain. In three orchards of pedunculate oak (Quercus robur L.) genetic variability of clones was analysed by nuclear, as well as chloroplast microsatellite markers. Genetic diversity of Croatian forest tree species is simultaneously being conserved using the ex situ statical method. Clonal seed orchards are a nucleus of forest genetic resource conservation, since the relationship between the size of population and the percentage of preserved heterozygosity is thus reduced to minimal loss of total additive genetic variability. Climate changes and new habitat conditions will pose additional challenges to seed production and forest management; in turn, this will influence their economic and social benefits, as well as biological diversity of forest ecosystems