Cucurbita maxima Duch. population analysis: relationship between Tunisian and Italian germplasm

Abstract

ABSTRACT Cucurbita maxima Duch. is one of the most diversified Cucurbita species worldwide. The objective of this study was to evaluate the genetic relationship between and within Tunisian and Italian Cucurbita maxima germplasm collections using morphological and molecular markers. The phenotypic parameters showed a large qualitative variability, primarily according to fruit-related traits, for both collections. The RAPD, ISSR and SRAP molecular marker systems used turned out to be effective in discriminating all the accessions. Among the Tunisian collection, the polymorphic information content (PIC) and genetic diversity (H) values were of 0.461 and 0.50 respectively, with a total of 96% of polymorphism detected. The Italian collection revealed a PIC and H values of 0.454 and 0.50 respectively and 90% of polymorphism. Population structure analysis reflected the geographical origin of the accessions and helped to classify the Tunisian collection into two populations and to group all the Italian accessions into one. The results suggest that the combination of morphological and molecular approaches is a highly reliable technique in studying and evaluating Cucurbita maxima germplasm which represents an important genetic resource to be preserved and used in breeding programs.