Résumé:
The present work aims to study the effect of salinity on the micropropagation and callogenesis of potato (Solanum tuberosum L.) in vitro and to compare the Physio-morphological and biochemical behavior of four varieties (Bartina, Spunta, Desiree, Timate). In this context a factorial experiment was conducted in a completely randomized block device (Latin square) with four concentrations of NaCl (CO: 0, C1: 25, C2: 50, C3: 150) male and four repetitions the work was performed on 64 experimental units in an MS environment and controlled conditions The physio-morphological and biochemical observations during the micropropagation show that the salt concentrations cause a progressive decrease in the length of the stems (LT) and the roots (LR), the number of leaves (NF) and roots
(NR) followed by a significant reduction of the fresh and dry weight of leaves and roots (PFf, PSf, PFr, PSr) for all the varieties studied. Chlorophyll (a, b) and potassium (K+) values in the leaves and roots are reduced under high concentrations of NaCl (150mMol) in the Désirée variety with an accumulation of sodium (Na+) in the leaves and roots and a rise in sugar level in the leaves (Suc). The group separation index from the analysis of variance indicates that specific behaviors between the two varieties Bartina and Désirée that seem more tolerant against the two other varieties Spunta and Timate present a strategy sensitive to salt stress . The results of the study on callogenesis capacities and the regeneration power under salt stress in vitro indicate that the four varieties showed clearly differentiated behavior. The sensitivity index (Is) confirms the sensation of the two varieties Spunta and Timate. comparing to the variety Bartina and Désirée which have a high rate of fresh and dry weight and a rate of increase of callus induction (cal%) with a high capacity of retentions of water (Ws) this tolerance under saline conditions is related to a proliferation of callus (CMR) . The results obtained suggest the possibility of using the in vitro technique for varietal selection under abiotic stress..
