Second year yield depression in seed production of subarctic Poa pratensis in South Norway

caracteres de rendimiento carbohidratos carbohydrates composante de rendement floraison induite glucide induced flowering inflorescence inflorescences inflorescencias localisation des productions macollamiento noruega norway poa pratensis production de semences production location racine rhizome rhizomes rizomas roots seed seed production semence semillas tallage tillering yield components