Molecular morphogical and physiological study in Tunisian wild wheat relative Aegilops geniculata Roth and wheat (Triticum durum Desf.) under salt stress

In this investigation, an attempt was made to assess the genetic diversity among thirteen Aegilops geniculata Roth populations and three durum wheat varieties originated from different bioclimatic areas using 19 RAPD markers. For morpho-physiological traits we have selected three populations of Aegilops geniculata and one variety of durum wheat from each bioclimatic area. This study has shown a high degree of variation of these characters mainly related to geographical origin. It was observed also that the Sbeitla population was less affected by the imposed salt stress than all the others while Ain zana was the most affected one. The CO2 assimilation rate, stomatal conductance, and intercellular CO2 for the three Ae. geniculata populations and wheat variety significantly decreased with increasing salt. Among the factors inhibiting photosynthetic activity, those of a stomatal nature had a greater effect. The molecular study indicated an important inter-specific polymorphism between Aegilops and durum wheat. Ae. geniculata populations revealed a high level of polymorphism (71.27%) than wheat cultivars (39.76%). Two main groups were represented by cluster analyses. The first group is formed by Ae. geniculata populations and the second is constituted only by durum wheat cultivars.