Quality and germination capacity of seed material harvested from an Arrhenatherion meadow

Arrhenatherion meadows are an endangered type of semi-natural grassland in Europe, and their conservation and restoration is an important policy objective. Recent research has led to development of techniques for harvesting seed material from regional donor sites and strategies for re-establishment of species-rich grassland, but their practical application requires that consumers are guaranteed sufficient seed quality of directly harvested material. Methods for the evaluation of purity, thousand seed weight (TSW) and germination capacity were developed and tested, a pre-condition to define the optimal seeding rate for this vegetation type (2000–3000 seeds m−2). The assessment was based on seed obtained by two harvesting techniques: on-site threshing (OST) and seed stripping (SS). Materials from both methods obtained 63% pure seeds. The TSW differed significantly between harvesting methods: the OST provided greater seed weight (1·057 g) than the SS (0·84 g). Two trials were implemented to define criteria for the germination capacity test. Organic growing media obtained the best and most homogenous results in a first comparative germination test. In the second trial, different dormancy-breaking treatments were compared, each with and without pre-chilling, namely: addition of potassium nitrate (KNO3), addition of gibberellic acid (GA3) and without addition of chemicals (WA). The germination capacity of the treated variants KNO3, GA3 and pre-chilling was lower than that for WA. The harvesting method significantly influenced quality and quantity of the seed material, whereas the substrate and dormancy-breaking treatments had no effect.