In vitro selection of somaclonal variant cells of Lycopersicon esculentum cv. Super strain B following exposure to osmotic stress.

Abstract

Callus was induced from seeds of tomato plant (Lycopersicon esculentum cv. Super strain B) on MS medium supplemented with 0.5 mg/L Naphthalene-acetic acid (NAA), 0.5 mg/L Indole-3-acetic acid (IAA), 2 mg/L Benzyl-aminopurine (BAP) and 2 mg/L Kinetin (Kn). This callus was subjected to osmotic stress using elevated concentrations of mannitol (0.0, 50, 100, 150, 200, 250 and 300 mM). The sub-lethal concentration which killed about 80% of callus cells (ID80) was determined to be 250 mM mannitol. The remaining 20% of cells which survived the sub-lethal concentration was selected visually and multiplied on the same medium composition and are considered somaclonal variant cells and designated as "selected callus line". Experiments were conducted to compare different metabolic activities of the selected callus line with the non-selected one (control callus, 0.0 mannitol). Results showed reduction in fresh weight of the selected line and non-significant reduction in relative water content (RWC) of both callus lines.