The Genetic Diversity Analysis of Tunisian Male Date Palm Cultivars (Phoneix dactylifera L.) Revealed by Phenotypic and Molecular Markers

Tunisian oases reveal an important genetic heritage of date palm cultivars, with various qualities of use. Since the beginning of the century, this heritage has evolved to a selective orientation based on the monoculture of "Deglet Nour," this orientation risks causing the loss of many cultivars. The male of the date palm is part of this heritage and so far remains marginalized. Although they are important for the date palm production cycle, it is in this context that lies our work to study the genetic diversity of a collection of male date palm pollinators from southern Tunisia. The morphological study of the 20 date palm pollinators using 45 IPGRI (International Plant Genetic Resources Institute) descriptors showed significant discrimination, with a similarity index ranging from 0.207 to 0.457, divided them into five similarity groups. The use of 7 ISSR (Inter Simple Sequences Repeat) primers resulted in 64 reproducible bands, of which 57 were 90% polymorphic, and statistical analysis showed a more or less significant genetic diversity with genetic distances 0.491 to 0.873. According to the Mentel test, a non-significant weak correlation (r = 0.015) was noted between the molecular and morphological data. However, the processing of molecular data by various methods generated very significant correlations. Indeed, the correlation between the SM (Simple matching) coefficient and the DICE coefficient showed an important correlation with r = 0.748, which confirms the discriminating power of the ISSR markers in studying the genetic diversity of date palm pollinators.