Seed Yield and Plant Regeneration of Different Subelover Cultivars in Southern Italy

摘要

Legumes are a fundamental resource for agro-ecosystem sustainability and because of their N-fixation capability they play an important biological role in the crop rotation and intercropping systems (Cazzato et al, 2003). As for annual legumes, cloversand medics are the species most utilized for Mediterranean pasture improvement (subclover in particular) while medics are best adapted to alkaline soil. As cover crop of the orchards, legumes reduce the use of N fertilization and herbicides while, in the sloping ground, they mitigate the water erosion. In general, subterranean clover matures during May, but there are large number of varieties representing a wide range of maturation dates. Cultivars are grouped according to the length of time required to reach maturity or seed set, as early, early mid-season, mid-season, and late-(Murphy et al., 1976). The earliest and latest strains may differ by as much as 60 days. Reseeding capability is a very important tool since it assures the species persistencethroughout the years. Subclover seed yield is strongly influenced by the grazing management and the intensity of plant defoliation. Previous researches on seed production and self seeding pointed out that subclover can produce seed under close grazing,unlike most other annual clovers (Evers and Smith, 1988). In this paper are reported the results obtained in a 3-year period on the comparison of different cultivars of subclover belonging to 3 different species: T. brachycalicinum Katznelson and Morley,T. subterraneum L., T. yanninicum Katznelson and Morley, with the aim to determine cultivars earliness, seed yield and hardseededness along with other parameters involved in seed production.