1 Seed multiplication of Trifolium alpinum: crop persistency and harvesting methods Peratoner G. 1, Gallmetzer W. 2, Klotz C. 1, Florian C. 1, Figl U. 1 and Pramsohler M. 1 1 Research Centre for Forestry and Agriculture Laimburg, Auer, Italy 2 Department of Hydraulic Engineering, Autonomous Province Bozen, Bozen, Italy

2 Introduction ○ The use of site-specific seed and plant material is important for achieving a successful and enduring restoration of extreme sites following natural or anthropic disturbance ○ Alpine clover (Trifolium alpinum) is a desirable seed mixture component for the ecological restoration of strongly acidic soils at high altitude 1, 2 References: 1 Krautzer et al. 2004, 2 Malaval et al. 2010

3 Which are the main constraints for the cultivation of Trifolium alpinum? ○ Specific soil requirements (no limestone, susceptibility to nematodes of the genus Pratylenchus) 1 ○ Extremely slow growth (poor competition against weeds, need for manual weeding) 1, 2 ○ Until now, successful seed multiplication was only achieved using transplants 3 References: 1 Peratoner et al. 2007, 2 Gallmetzer & Florineth 1996, 3 Peratoner et al considerable production costs!

4 Experimental questions ○ Which is the crop persistency of Trifolium alpinum if cultivated for seed production? Can the costs for crop establishment be distributed over several harvest years? → How do yield-related traits and seed yield develop over time? ○ Is a mechanised harvest of Trifolium alpinum feasible?

5 Material and methods (1) ○ Experimental site: plant garden Prettau (1600 m a.s.l., South Tyrol, Italy), soil pH 5.6, 81 mg g -1 humus content, no limestone) ○ Trial establishment in 2006 using 5 month-old container-grown plants grown in a commercial substrate ○ Manual weeding of trial

6 Material and methods (2) – trial design ○ Factors 1.Inoculation of transplants with a thin top soil layer of soil from the seed collection site (yes/no) 2.Harvest method (manual/mechanised → motor- powered, portable harvesting device) 3.Harvest year (2008 to 2011) ○ Design: split-plot block design (harvest method as split factor) with 4 replications ○ Statistical analysis with a mixed model (harvest year as repeated factor)

7 ○ In 0.25 m²-permanent observation subplots: Projective cover of Trifolium alpinum Density of ripe and unripe infructescences at harvest time ○ In whole plots: Seed yield Thousand Seed Weight (TSW) Proportion of empty florets Material and methods (3) – data collection

8 Results (1) - Inoculation Inoculation absent present

9 Results (2) – Harvest year Data of 2007 are summary values of two harvest dates

10 Results (3) – Harvesting method Trait Harvesting method P-value of effect manualmechanised TSW (g) Seed yield (kg ha -1 year -1 )

11 Conclusions ○ In accordance with what already known for other alpine legumes, the seed production is reasonably limited to two harvest years only ○ The mechanical harvest seems to be a viable alternative to the manual harvest, but it results in lower seed yield and may be critical in the first harvest year (lack of compact ripening)

12 Thank you for your attention. Thank you for your attention