The main objective of this study was to investigate the efficiency of RAPD, AFLP and SAMPL marker systems in detecting genetic polymorphism in cowpea landraces that probably share a similar genetic pool. A second objective was to determine the level of diversity among landraces from a restricted area in order to define the most appropriate strategy of on-farm conservation. Each marker system was able to discriminate among the materials analysed, but a clear distinction between all the local varieties was only obtained with AFLP and SAMPL markers. The average Diversity Index was quite similar for each marker system, but due to the differences in the Expected multiplex ratio values, the Marker Index was higher for the AFLP and SAMPL systems than for RAPD. The AFLP and SAMPL techniques appear to be more useful than RAPD in the analysis of limited genetic diversity among the cowpea landraces tested. The significant correlations of SAMPL similarity and cophenetic matrices with those of the other markers and the lower number of primer combinations required, indicates that this technique is the most valuable. The low genetic similarity detected among landraces suggests that all the cowpea landraces should be maintained on the respective farms from which they came.
Efficiency of three PCR-based markers in assessing genetic variation among cowpea (Vigna unguiculata subs. unguiculata) landraces
NEGRI, Valeria
2002
Abstract
The main objective of this study was to investigate the efficiency of RAPD, AFLP and SAMPL marker systems in detecting genetic polymorphism in cowpea landraces that probably share a similar genetic pool. A second objective was to determine the level of diversity among landraces from a restricted area in order to define the most appropriate strategy of on-farm conservation. Each marker system was able to discriminate among the materials analysed, but a clear distinction between all the local varieties was only obtained with AFLP and SAMPL markers. The average Diversity Index was quite similar for each marker system, but due to the differences in the Expected multiplex ratio values, the Marker Index was higher for the AFLP and SAMPL systems than for RAPD. The AFLP and SAMPL techniques appear to be more useful than RAPD in the analysis of limited genetic diversity among the cowpea landraces tested. The significant correlations of SAMPL similarity and cophenetic matrices with those of the other markers and the lower number of primer combinations required, indicates that this technique is the most valuable. The low genetic similarity detected among landraces suggests that all the cowpea landraces should be maintained on the respective farms from which they came.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
