In vitro salinity screening of garlic (Allium sativum L.) via shoot tip culture under NaCl stress

Salinity is one of the major abiotic stresses limiting plant growth and agricultural productivity worldwide. This study investigated the effects of NaCl induced salinity stress on the in vitro growth of garlic (Allium sativum L.) plantlets derived from shoot tip culture. Shoot tip explants of Taşköprü garlic were cultured on Murashige and Skoog (MS) medium supplemented with 0, 100, 200, and 300 mM NaCl. Shoot fresh weight (SFW), shoot dry weight (SDW), shoot length (SL), dry matter content (DMC), and infection rate were evaluated on the 7th, 14th, 21st, and 28th days of culture. NaCl stress generally reduced growth parameters in a concentration dependent manner. While 100 mM NaCl caused moderate inhibition, maintaining growth parameters at approximately 77-80% of control values, concentrations of 200 mM and above resulted in severe suppression of shoot growth and biomass accumulation. Shoot length exhibited the strongest linear response to NaCl concentration on the 28th day (y = -0.143x + 55.82; R² = 0.917), confirming its reliability as a salinity stress indicator in garlic. These findings confirm the salt sensitivity of garlic under in vitro conditions and demonstrate that shoot tip culture is an effective system for salinity tolerance screening. Shoot length and shoot fresh weight are proposed as key morphological indicators for evaluating NaCl stress responses in garlic.