In this study, the effect of different doses of foliar melatonin application on the leaf and bulb properties of onion under salt stress was investigated for
the first time. Four commercial varieties were used as plant materials. One 1μM, 2 μM, 4 μM, and 8 μM doses of melatonin were applied to the plants
at the seedling stage by leaf spraying two times. Salt stress was created by an irrigation programme containing 0, 100 mM, 200 mM, and 400 mM NaCl.
At the end of the study, 13 morphological traits that play an important role in onion cultivation were observed. As a result of the study, it was found
that the combined effect of three factors for the number of bulb scales and bulb weight traits is statistically significant. Overall, it has been observed that
melatonin has the potential to counteract the negative effects of salt stress for some traits. However, different results between genotypes revealed that
similar field trials should be tested with different genotypes to determine the appropriate melatonin dose in onion plants.