In vitro screening of seeds of local castor accessions ( Ricinus communis L.) under salt stress conditions

Castor ( Ricinus communis L.) is an undemanding plant whose cultivation offers enormous economic potential for Senegalese farmers. The identification of high-performance genotypes with acceptable yields in salt stress conditions is one of the solutions to promote this crop on soils that are unaffected by food crops. Four local castor accessions were cultured for one month on modified Murashige and Skoog (MS) media and added with 0; 25; 50; 100 and 150 mM sodium chloride (NaCl). Accession responses were evaluated under in vitro conditions on the basis of morphological, biochemical and survival parameters of vitroplants. The effect of salinity on these measured parameters enabled to classify accessions tolerant group (acc1), moderately tolerant (ACC7) and sensitive (ACC3 and ACC4). The 50 mM concentration of NaCl was identified as a critical and discriminating tolerance threshold allowing classification of castor accessions according to their sensitivity to NaCl. Aerial biomass has emerged as a relevant criterion for classifying castor accessions. Measurements of the leaf chlorophyll contents of vitroplants led to the same classification of the groups.