Breeding of new European plum (Prunus domestica L.) cultivars faces two major problems: low fruit set in cross-pollination and low germination rate of the seeds obtained from the harvested fruit. Up to now, breeding programs reported mainly stratification in peat, soil or sand and embryo culture according to Theiler (1971) in order to avoid the need of stratification and its associated problems, such as high losses due to microbial infection. The in vitro technique used in this study combines elements of different reported stratification methods and minimizes the infection rate during the stratification. Seeds were placed in a modified Murashige and Skoog (MS) medium in test tubes. Two seed treatments were tested: 1) sowing and stratification immediately after the harvest, 2) seeds were dried and stored for four months prior to sowing and stratification. Stratification was carried out in vitro at 4°C in both cases. Germination was checked once a week. When the radicle emerged through the surrounding tissues, seedlings were removed from the test tubes and cultivated in soil in the greenhouse. Some hard seed coats were removed manually to relieve the radical from the hardened testa and to encourage seeds germinate. The germination rate ranged from 16--100{%}. By comparing the two treatments it is obvious that if the seeds are sown immediately after harvest, the germination percentage is higher.     «

Breeding of new European plum (Prunus domestica L.) cultivars faces two major problems: low fruit set in cross-pollination and low germination rate of the seeds obtained from the harvested fruit. Up to now, breeding programs reported mainly stratification in peat, soil or sand and embryo culture according to Theiler (1971) in order to avoid the need of stratification and its associated problems, such as high losses due to microbial infection. The in vitro technique used in this study combines el...     »