SCREENING TEST In vitro BY THE APPLICATION OF SALT STRESS ON FRIABLE CALLUSES OUTCOME FROM FOUR GENOTYPES OF CITRUS ROOTSTOCKS

Salinity is an abiotic constraint, the consequences of which affect both the production and the quality of citrus fruits. The use of rootstocks resistant and / or tolerant to this stress is necessary to overcome this problem. This work aims to compare in vitro, the behavior of callus of citrus rootstocks with respect to successive concentrations of NaCl, on morphological and physiological parameters, such as: fresh weight; Dry weight; Callus growth, proline content; Total sugars content, and Chloride content. Calli tested in vitro of eight rootstock genotypes including: Poncirus trifoliata (PT), citrange Carrizo (CC), Citrumelo 4475 (C); Citrus volkameriana (CV), citrange Troyer (CT), Citrandarin (CD), Lime rangpur (LR), Mandarin cleopatre (MC), induced in MT medium (Murashige and Tucker), with the presence of 2,4-D (2,4-dichlorophenoxyacetic acid) , and BAP (Benzylaminopurine), then transferred to MT medium (Murashige and Tucker), added successive concentrations of sodium chloride: NaCl (1 g / l; 3 g / l; 6g / l), for a period of 2 months. The results obtained show that the application of stress leads to a decrease in fresh weight, and dry weight, as well as the growth of calluses compared to control callus. On the other hand, there is an increase in the content of proline, and total soluble sugars, as well as the significant accumulation of chloride ions in stressed calluses, compared to control calluses. The accumulation of proline and total soluble sugars could be an indicator of tolerance to salinity in the callus of the rootstocks studied.