Proline synthesis and physiological response of cassava genotypes under in vitro salinity/Sintese de prolina e resposta fisiologica de genotipos de mandioca sob salinidade in Vitro

The objective of this research was to evaluate the proline synthesis and physiological response of cassava genotypes which were micro propagated and induced to salinity stress in vitro. Micro cuttings of approximately 1.0cm long with a single bud of genotypes TBRS Tapioqueira, BRS Verdinha and Lagoao which were previously established in vitro were inoculated in a MS medium containing different concentrations of NaCl (0; 25; 50; 75; 100mM) and were analyzed after 90th day for: number of roots, number of leaves and shoot dry mass. The proline content of BRS Tapioqueira and Lagoao was assessed at 30th, 60th and 90th day. There was no analysis of proline of the variety Verdinha because of the contamination of the explants. The experimental design was completely randomized in double factorial scheme (3 genotypes x 5 salt treatments), with seven repetitions for growth variables. For comparing proline content, completely randomized design was used in a plot subdivided in time, with genotype and NaCl factors in plot and time in subplot, with two repetitions. For r time and genotypes Tukey test (P