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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.56

GENETIC DIVERSITY AND POPULATION STRUCTURE OF A PHASEOLUS VULGARIS L. LANDRACE MAINTAINED ON-FARM IN CENTRAL ITALY (LAZIO)

B. TIRANTI, V. NEGRI

Department of Plant Biology and Agro-environmental Biotechnology, Section Genetics and Breeding, University of Perugia, Italy, Borgo XX Giugno 74, 06021 Perugia

Landrace, Phaseolus vulgaris, SSR, genetic diversity, on-farm conservation

Landraces are balanced, variable populations, susceptible to change in response to environmental and human selective pressures (Harlan, 1975). They present two different levels of genetic diversity: among populations and within population. Population structure of landraces is mostly unknown (Frankel et al., 1995). Several authors showed that a high degree of diversity is maintained in landraces of autogamus species from comparable ecogeographic sites.

Landraces are still maintained in central Italy. Some landraces of Phaseolus vulgaris, which have been maintained on farm due to adaptation to particular situations, are nowadays cultivated and sold at very high prices due to their organoleptic characteristics. Among them our attention is focused on the ‘A pisello’ landrace from Colle di Tora (Rieti), which, due to particular social reasons, is running the risk of extinction.

In order to define managing strategies to preserve this landrace for the future, we studied the genetic structure of ‘A pisello’ populations grown by different farmers and levels of variability among and within populations by using SSR molecular markers.

The high differentiation found in the metapopulation, can be explained by the high sensibility of SSR, isolation of sub-populations during their cultivation, their small size and limited exchange of seeds between farmers.