Knowledge of the existing levels of diversity is fundamental for planning in situ (on-farm) conservation activities. Three neighbouring cowpea landraces (LRs) still grown in central Italy, were studied by amplified fragment length polymorphism (AFLP) and selectively amplified microsatellite polymorphic locus (SAMPL) markers to determine the distribution of genetic variation within and among them. The LRs being studied, although relatively similar, are well differentiated from one another as shown by the significance of the Fisher exact test for the genic differentiation and the absence of genotype sharing among LRs. AFLP and SAMPL and their combined data also show a relatively high level of diversity still present within LRs. The more efficient SAMPL technique gave a better discrimination of the plants than AFLP. The LRs under study appear to be structured as a metapopulation in which a substantial differentiation is maintained at the subpopulation level. A complex interaction of factors (drift, LR isolation, farmer selection, migration within LRs) explains the observed pattern of diversity. This study suggests that the best strategy for maintaining diversity in the area is to preserve each of the examined LR on the farms from which it came.
On-going on-farm microevolutionary processes in neighbouring cowpea landraces revealed by molecular markers
NEGRI, Valeria
2005
Abstract
Knowledge of the existing levels of diversity is fundamental for planning in situ (on-farm) conservation activities. Three neighbouring cowpea landraces (LRs) still grown in central Italy, were studied by amplified fragment length polymorphism (AFLP) and selectively amplified microsatellite polymorphic locus (SAMPL) markers to determine the distribution of genetic variation within and among them. The LRs being studied, although relatively similar, are well differentiated from one another as shown by the significance of the Fisher exact test for the genic differentiation and the absence of genotype sharing among LRs. AFLP and SAMPL and their combined data also show a relatively high level of diversity still present within LRs. The more efficient SAMPL technique gave a better discrimination of the plants than AFLP. The LRs under study appear to be structured as a metapopulation in which a substantial differentiation is maintained at the subpopulation level. A complex interaction of factors (drift, LR isolation, farmer selection, migration within LRs) explains the observed pattern of diversity. This study suggests that the best strategy for maintaining diversity in the area is to preserve each of the examined LR on the farms from which it came.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
