Liquid sorting and film coating : techniques for improving tree seed performance

Tree seed performance has benefited considerably from the development of controlled methods to overcome dormancy. Traditionally tree seeds have often been stratified outdoors. Depending on the types of dormancy, stratification starts before or during summer and continues during winter, or it starts before winter. Seeds become ready to germinate during winter, and they may start to germinate before sowing. Reducing the water content of the seeds during pre-treatment can prevent this premature germination. If premature germination is prevented, treatments at slightly reduced and controlled moisture content (MC) can be prolonged. As a result, percentage, rate, and uniformity of germination increase. Moreover germination proceeds over a wider range of seedbed conditions. So far, controlled MC treatment has been developed for about 20 species, both broad leaved and conifers