Joint research conducted by Metla and the University of Oulu showed that the current pretreatment methods can be applied also on spruce seed lots to separate live and dead seeds from each other. The treatments do not change the actual structures of the seeds, but maturity and possible structural injuries are critical to the success of the treatments.
The results of the pretreatments and storage are affected by the chemical maturity of the seed’s surface layers; maturity is reached several weeks after the embryo is full-sized. Hence, cone collecting should not be started until the end of October, which applies to seed orchards, too.
The germination capacity of spruce seeds changed at high and low temperatures used in the study. The optimal temperature range for seed extraction and other pretreatments was 20-25 ºC, which is the range of optimum temperatures for germination.
The health and maturity of the structures also turned out to be important factors in controlling storage viability. During short-term freeze storage (-18 ºC ) of one to three years the germination capacity of seed orchard seeds remained stable, but the germination rate was impaired already during one year of storage. During long-term storage of ten years both the germination capacity and the rate were impaired.
The study was funded by Forelia Ltd and Metsämiesten Säätiö Foundation.
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