Exploitation de la diversité génétique des espèces sauvages dans l’amélioration des paramètres physiologiques et agronomiques et de la réponse au stress salin chez le blé dur
Abstract: Exploitation of the genetic diversity of wild species in durum wheat improvement and its tolerance to salinity This study aimed to evaluate the performance and tolerance to salinity of 67 lines derived from crosses of durum wheat varieties with wild species Triticum bicornis, Triticum boeoticum, Triticum dicoccoides, Triticum urartu and Aegilops speltoides. These lines along with the checks were evaluated for yield and yield components, total biomass and physiological parameters (Chlorophyll fluorescence and canopy temperature) in a trial conducted at Marchouch experiment station. The tolerance to salinity was conducted in hydroponic system. The analysis of variance did not show significant differences among the lines for the canopy temperature but the differences were significant for chlorophyll fluorescence parameters. The lines issued from crosses Cham5 /Aegilops speltoides et Cham5 *2 /Triticum boeoticum, Cham5 *4 *3 /Triticum boeoticum showed high values for chlorophyll fluorescence parameters. For agronomic performance, the lines Cham5 /Triticum urartu, Cham5 *2 /Triticum urartu, Haurani *2 *3 /Triticum boeoticum, and the checks Icarachaz and Marzak showed earliness and good plant height. The lines derived from Cham5 /Triticum boeoticum had highest total biomass and 1000 kernel weight, along with high grain yields. Two varieties of the checks Icarachaz and Marzak had the highest harvest indices. No significant differences were found among the lines for all the yield components. The second study showed that salinity stress at 150mM NaCl had major effects on the growth and development of 70 lines tested as reflected by the reduction of roots and shoots. The genotypes derived from crosses Cham5 *3 /Aegilops speltoides, Cham5 *2 /Triticum dicoccoides, Cham5 *4 *4 /Triticum urartu, Bezaghras/ Aegilops bicornis// Bezaghras/3/Marzak, Segndroue/ Aegilops bicornis /Aegilops speltoides, Haurani *2 //Segndroue/3/Ouassara et *2 Cham5 /Triticum urartu are less affected by salinity stress. Based on our results, the wild relative species Triticum dicoccoides, Aegilops speltoides, Triticum urartu, et Aegilops bicornis are an important reservoir of adaptive genes for use by durum wheat breeding programs to enhance productivity, tolerance and resistance to abiotic and biotic stresses.