Protocol for Doubled-Haploid Micropropagation in Quercus suber L. and Assisted Verification

Cork oak (Quercus suber L.) belongs to the family Fagaceae. The tree is robust, up to 20 metres high. The stem may reach 2 metres of diameter. The main raw material produced by this forest species is the corky bark. The cork is a demanded product of economic importance, sustaining an active cork industry. The most valuable manufacture is the cork stopper for wines of high quality.

This forest species has serious drawbacks for the deployment of the classical genetic improvement programmes, mainly based on: 1) its long life and irregular reproductive cycle; 2) low correlation between traits at the juvenile and adult phases; 3) late sexual maturation; 4) the difficulty of seed conservation and of vegetative reproduction; 5) difficulty for the establishment of seed orchards; and 6) the impractical method of repeated backcrossings for the production of pure lines. Somatic embryogenesis has been used to solve the problem of rapid plant propagation of selected trees. A different approach is based on the production of pure lines through doubledhaploid plant regeneration from gametic embryos induced in anther culture.