Abstract
Morpho-agronomical traits and Inter Simple Sequence Repeats (ISSRs) were used to investigate the genetic diversity in ten spontaneous populations of Tunisian tall fescue (Festuca arundinacea Schreb.), and to assess their relationships with three local cultivars as well as their ability to provide specific markers suitable in germplasm conservation and plant breeding method. Principal component analysis based on morpho-agronomical data revealed that both wild populations of Bizerte and Borj Massoud have an important agronomic potential with a significant seed production and a substantial forage yield. These populations, characterized by higher agronomical potentiality than the local cultivars, will be suitable in a selection program for improving tall fescue in the north of Tunisia. The close connection of the wild form with the local cultivars presenting a limited agronomical performance, suggested a substantial gene flow caused by the limited geographical areas in the north and northwest of Tunisia. A large genetic diversity as related to ISSR patterns was revealed within the Tunisian tall fescue germplasm. The number of ISSR fragments generated per primer set ranged from 7 to 16 with a mean of 10.7 bands by primer. A total of 120 ISSR fragments were detected, 107 of which were polymorphic (89.17%). In addition, the ISSR phylogram exhibited a great molecular similarity of the spontaneous populations with cultivars. A non-significant correlation between morpho-agronomical traits and ISSR markers was detected. The patterns of variation which appeared to be consistent for the two studied marker systems can be used for designing breeding programs, conservation and management of tall fescue genetic resources.