Eila Tillman-Sutela, Anu Hilli and Anneli Kauppi Finnish Forest Research Institute and University of Oulu Oulu Muhos Helsinki Arctic Circle Rovaniemi Germination changes of Picea abies seeds at water-based pretreatments

INTRODUCTION Pretreatments are a prerequisite for a mechanized seedling production in modern forest tree nurseries. The goal is to achieve a homogenous seed lot - germination capacity and rate of at least 95 %. Seed extraction is only the first step in a multi-phased procedure preceding sowing. Conifer species have a high genetic control over germination attributes and their differences between and within species. Structural differences in the seed coat and nucellus cause functional differences between moistened spruce and pine seeds. Results of ecological studies suggest that pretreatment conditions should be customized for different seed species. Highly mechanized treatments tend to be homogenized using water and elevated temperatures to accelerate the process. Pretreatments of spruce seeds have been reduced to a minimum due to unpredictable results.

The aim of our study was to find out: 1.changes in the germination attributes of Norway spruce seeds during the multi-phased pretreatment chain, 2.impact of seed structures on the changes of germination attributes from cone collection to storage 3.effect of storage on germination attributes of IDS-treated spruce seeds.

1200 l of cones collected in February 2001 Extraction using water 580 l in airflow 20 ºC 40 l, control without water 580 l 38 ºC De-winging Water cleaning Drying Mechanical cleaning Storage 90 d, -3 ºC MATERIAL AND METHODS IDS-treatment: Moistening, 20 ºC, 16 h Incubation, 5 ºC, 24 h Desiccation, 20 ºC Separation 11 fractions Drying, 20 ºC Storage, -18 ºC phases by hand, 20 cones Radiography Germination tests, ISTA Moisture content measurements Floating tests Microscopy Tukeys multiple comparison test paired t-test

1 = Initial germination 2 = Extraction 3 = Dewinging 4 = Water cleaning 5 = Drying 6 = Mechanical cleaning 7 = Storage 90 d, -3 ºC 8 = Initial moistening 9 = Incubation 24 h, 5 ºC 10 = Desiccation 45 min 11 = Storage drying Fr 1 12 = - "- Fr 2 13 = - "- Fr 3 14 = - "- Fr = -"- Fr 11 Changes in germination parameters of dry-extracted spruce seeds at different pretreatment phases Germination Germination rate Changes in germination parameters of water-extracted spruce seeds at different pretreatment phases IDS

Opened seed coat in a moistened fungi-infected spruce seed. Opened micropyle of the seed coat in a moistened spruce seed. Spruce Large nucellar cap covers about ¾ of the length of the micropylar end of the spruce seed.

The changes of germination parameters in dry-extracted, IDS-treated seed fractions after one years storing at –18 C The changes of germination parameters in water-extracted, IDS-treated seed fractions after one years storing at –18 C % Fr Germination capacity Germination rate % Fr Germination capacity Germination rate

CONCLUSIONS Separation of spruce seeds succeeded well according to the principles of the IDS-method, even if the germination parameters in the fungi-infected seed lot did not reach 95 %. The result was achieved using a surprisingly short incubation time compared to the experiences in pine seeds. Short incubation time may be favourable to Norway spruce seeds because of the rapid opening of the seed coat in moistened seeds. Restriction of water and lowering of temperature at least at the extraction phase of winter-collected spruce cones should be considered. The results need verification using good quality seeds collected in consecutive months.

Mechanical cleaning Pretreatment of forest tree seeds from cone collection to nursery sowing Cone collection Storage Seed extraction De-winging Water cleaning SowingStorage Drying PREVAC IDS (Incubation· Desiccation· Separation· Storage drying) Sowing in nurseries