The effect of agronomic factors on seed and forage production in perennial legumes sainfoin (Onobrychis viciifolia Scop.) and French honeysuckle (Hedysarum coronarium L.)

Perennial legume varieties and ecotypes belonging to the species sainfoin ( Onobrychis viciifolia Scop.) and French honeysuckle ( Hedysarum coronarium L.) were investigated under different management treatments (two regimes of irrigation, cutting and seeding densities) at the Forage Crops Institute in Foggia, Italy (which has a typical Mediterranean environment) for two seasons, 1990 and 1991. Dry-matter production, seed production and seed yield components were affected more by harvest year and irrigation than by seeding density. Mean increases due to irrigation were 2·8% and 60·6% respectively for dry-matter and seed yield in sainfoin and 35·3% and 32·5% respectively in French honeysuckle. Under both cutting regimes, the higher seeding density was more suitable for sainfoin, increasing stems m^?2 with irrigation and seed yield without irrigation. In French honeysuckle the lower seeding density was more suitable for production of inflorescences per tiller and for seed weight without irrigation. Higher seeding density positively influenced seed yield under irrigation. The seed yield components most influenced by irrigation were: 1000-seed weight, seeds per inflorescence and inflorescence per stem. French honeysuckle genotypes were potentially more productive in dry matter and seed yield under both irrigation regimes than the sainfoin, which was more productive in seed yield when cut. The ecotypes of both legumes represent a genetic resource, particularly for seed yield after forage cutting, to be utilized in breeding programmes for developing varieties well adapted to Mediterranean environments.