Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

ECOGEOGRAPHY OF PERENNIAL FORAGE LEGUMES IN CENTRAL AND SOUTH ITALY

RUSSI L.*, PAGNOTTA M.A.**, PORQUEDDU C.***, COCKS, P.S.****

* Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali. Università degli Studi di Perugia, Borgo XX Giugno 74, 06121 Perugia

lrussi@unipg.it

** Dipartimento di Agrobiologia e Agrochimica, Università della Tuscia, Via S. C. de Lellis, Viterbo

pagnotta@unitus.it

*** Centro di Studio sui Pascoli Mediterranei (CNR), Sassari

porquedd@hpj.area.ss.cnr.it

**** University of Western Australia, Nedlands, Perth, WA 6907, Australia

pcocks@agric.uwa.edu.au

forage perennial legumes, genetic resources, soil salinity, farming systems

Dryland salinity in mediterranean Australia is at present affecting almost 2 million ha, and the loss of soils is sharply increasing. This is caused by the rising of saline groundwater as consequence of low water use by shallow rooted annual crops and pasture. To prevent degradation is necessary to reintroduce in the farming system deep rooted perennial species better able to use rainfall water and avoid its accumulation in the groundtable all around the year. In areas with soil pH from neutral or alkaline lucerne is already being introduced with success. The problem do exist in areas with acid soils, where adapted, well known perennial legumes are scarce. In order to single out species with potential it is important to understand their distribution and adaptation in natural ecosystems and to study their variability between accessions. While the ecology of annual self re-seeding pasture legumes in areas with a Mediterranean climate is well known, literature about perennials is scarce. Some information is available for species of agricultural importance such as lucerne, sainfoin, sulla, white and red clovers, where breeding is being playing a major role. However, the flora of the Mediterranean Basin is very rich of legumes, including perennials, which are likely to be a valid alternative to annuals in the farming system.

A total of 79 sites were surveyed, 24 scattered in central Italy, 26 in Calabria and Sicily, and 29 in Sardinia. At each site the legume botanical composition was assessed, recording presence and abundance of species, site information (geographical data, aspect, slope, depth of soil, drainage, grazing pressure, etc.) and collecting a soil sample, subsequently analysed for physical and chemical properties. Climatic data of each site (mean minimum temperature of the coldest month, mean maximum temperature of the warmest month, total annual rainfall and number of rainy days) were also recorded, downloading them from the WEB site of UCEA, the Central Office of Ecological Agriculture. Germplasm of available perennial legumes have been collected from each site during the summer 1999 and evaluated.

A total of 147 legume species were identified, of these 94 were annuals and 53 perennials. Canonical correlation analysis was firstly performed in order to ascertain the relationship between environmental factors (climate, soil and site characteristics) and perennial legume species (only those found in above 6% of the sites were included in the analysis). K-Mean clustering was also performed separately for soil and climate, assigning sites and frequency of species in any present cross-combinations of soil and climate clusters. The most common perennial species were Trifolium pratense, T. repens, and Lotus corniculatus. Onobrychis viciifolia was found only in Central Italy, while Hedysarum coronarium basically in Sicily. Medicago lupulina, Vicia cracca, T. resupinatum and Psoralea bituminosa were also common. The most important environmental factors which affected species distribution and abundance were: temperatures (minimum and maximum), pH, OM, altitude and phosphorus.