The European Ryegrass Core Collection: A Tool to Improve the Use of Genetic Resources

A core collection of 162 populations of ryegrass (Lolium perenne) native to 18 European countries, is being evaluated across Europe in a multi-country trial. Each participating country contributed the lesser of 10% or 25 accessions from its collection of native populations. The accessions are being grown at 18 sites in 17 countries. Quick, cheap protocols were developed for evaluation. Preliminary results are presented for performance during the first winter. Populations of northern origin showed uniformly low winter damage and low winter growth at all evaluation sites. Populations of Mediterranean origin were more affected by the environment used for evaluation, developing higher winter yield at sites with mild winters, lower winter yield where winters were colder, and suffering severe damage at sites with the coldest winters

Productivity and canopy modification of Medicago arborea as affected by defoliation management and genotype in a Mediterranean environment

Medicago arborea is one of the most potentially valuable fodder shrubs in a Mediterranean environment because of its high preference by small ruminants and its nutritive value. Edible biomass production is affected by agronomic and environmental factors. A study, carried out in an inland area of Sicily in the growing seasons of 1994/95, 1995/96 and 1996/97, evaluated the forage production and canopy modification in a M. arborea plantation after (i) commencing defoliation 1 or 2 years after transplanting and (ii) defoliating only in autumn (A), only in early summer (S) or in both seasons (A and S). Six clones derived from five different Mediterranean populations were used. Plant age at the first defoliation did not significantly influence forage production. The genotypes differed in growth rate and forage production. The season and frequency of defoliation markedly influenced forage production and canopy size. The highest annual production was obtained by defoliating once a year in early summer (on average, 1Æ65, 2Æ85 and 4Æ50 tonnes ha)1 respectively in the three growing seasons). With the A and S, and A defoliation treatments, production decreased over 3 years by, on average, 0Æ19 and 0Æ57 respectively, but the differences became more marked over a 3-year period. Defoliating only in early summer, however, resulted in an excessive shrub height (>120 cm, 3 years after transplanting), thereby increasing problems of accessibility to small grazing ruminants, and possibly necessitating cutting. On the contrary, the A and S defoliation made it possible to limit the height to <90 cm