The first efficient cryopreservation procedure for in vitro-grown shoot tips of raspberry (Rubus idaeus L.) has been developed based on encapsulation-vitrification (EnVi) and encapsulation-dehydration (EnDe). EnVi resulted in higher survival (85%) and regrowth (75%) of cryopreserved shoot tips than EnDe (65 and 50%, respectively). In both cryogenic procedures, shoots regenerated from cryopreserved shoot tips without intermediary callus formation. Histological studies showed that a much larger number of meristematic cells survived following EnVi than EnDe. The EnVi procedure was applied to seven raspberry genotypes with an average survival and regrowth of 71 and 68%, respectively. Regenerated plants showed normal morphology. Results here indicate EnVi as a simple and efficient method for long-term preservation of R. idaeus germplasm.

Summary — A 5-wk factorial experiment was conducted to examine the effects of osmocote (18N:11P:10K; commercial controlled-release fertilizer), rock phosphate and 3 species of arbuscular mycorrhizal fungi on the growth of the strawberry cultivar Senga Sengana in a peat-sand-vermiculite substrate. Three Glomus species, G98 (probably G intraradices), G128 (an undescribed species) and G geosporum were compared. G98 and G128 significantly increased shoot dry weights compared with the non-mycorrhizal control. Levels of root colonization by G98 and G128 were significantly greater than by G geosporum. The addition of both fertilizer types significantly increased shoot dry weights. Neither osmocote (0.5-2.0 g/l) nor rock phosphate (1.0-5.0 g/l) addition had a significant effect on colonization by the 3 fungi. An osmocote fertilizer applied at 25% of the minimum recommended commercial rate to mycorrhizal plants was sufficient to produce equivalent dry matter yields as non-mycorrhizal plants receiving the

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Cryopreservation of dormant buds can be a feasible method for long term preservation of clonally propagated woody plants.In the present study, dormant buds of blackcurrant (Ribes nigrum L) cultivar Mortti were cryopreserved. Twig segments from greenhouse and field grown plants were cooled at their natural moisture content at the rate of 0.17 °C min −1 from zero to −38 °C, immersed in liquid nitrogen and stored in liquid nitrogen vapor. The post-cryopreservation regrowth of buds was evaluated in vitro and viability of recovered plants was tested in vivo. The estimated recovery rate for buds thawed after 1-6 days in cryostorage was 86% and 66% for outdoor and greenhouse grown buds, respectively. Microplants adequate in size and quality grew successfully in vivo and plants produced berries in field. After 4 years in cryostorage, the estimated recovery rate for outdoor buds was 58%. According to results from 1 to 6 days cryostorage, the tested dormant bud protocol turned to be applicable for cryopreservation of the blackcurrant cultivar Mortti. However, concerning the long-term preservation the decline of recovery is important to consider in the future experiments. Key messageThe cryopreservation of dormant buds combined with in vitro recovery provides a feasible tool for conservation of plant genetic resources of blackcurrant.

Worldwide interest in soil quality evaluation has increased rapidly throughout the past decade, prompting us to evaluate the long-term impact of four cropping systems on several biological, chemical and physical determinants of soil quality. We hypothesized that after 17 years several of the determinants would show significant differences between conventional cereal and low input/organic rotations. Four crop rotations were imposed on a silt soil from 1982 through 1999. Rotation A was a conventionally managed cereal rotation that received 100% of the recommended mineral fertilizer each year. Rotation B was also managed conventionally from 1982 until 1993, although it received only 50% of the recommended mineral fertilizer. From 1994 through 1999, rotation B was managed as an organic rotation. Rotations C and D were low-input rotations with plant residues returned either untreated (C)or composted (D)from 1982 until 1994.From 1994 through 1999,they were also anaged organically. Significant decreases in extractable phosphorus (P)and potassium were observed in rotations C and D compared with rotation A, presumably because their yearly nutrient inputs were somewhat lower. The amount of soil organic carbon (Corg), soil water holding capacity, the numbers and biomass of earthworms and the microbial biomass carbon and nitrogen were or tended to be higher in low input/organic than in conventionally managed plots. These effects may be in connection with the slightly increased levels of Corg in soil of the organic rotations. Activities of twelve enzymes were strongly affected by sampling time (early-versus late-summer), but much less by long-term management. Litter decomposition, numbers of soil nematodes, arbuscular mycorrhizal (AM)fungal diversity,AM spore density and AM functioning were little affected by rotation. However,AM spore density correlated positively with the high amounts of extractable calcium and P which were a result from excessive liming applied to some plots in 1982. The crucial question to be answered in future is whether plant growth and yield will correlate with the changes in soil properties. This question will be dealt with in a further paper using data from the same experiment.;