Effectiveness of Acid Gibberellic and Magnetic Field on Shelf Life and Post-Harvest Life of Strawberry cv. Selva under Temperature Stress Conditions

 Strawberry is one of the most important small fruits in the world, which is cultivated as a perennial plant in temperate regions of the world. Ripe strawberry fruit contains compounds such as protein, fiber, sugars such as fructose, glucose, sucrose, organic acids, vitamins, minerals, as well as phenolic compounds and anthocyanins. The aim of this study was to investigate some hormonal treatments and magnetic field on some physiological and biochemical characteristics, shelf life and postharvest life of strawberry cv. Selva under temperature stress.

 This experiment was performed as a split plot based on a completely randomized design with 3 replications. Physiological and biochemical characteristics were studied on several tissues of Selva strawberry cultivar under several different temperature treatments. The treatments were gibberellic acid at three levels of control, 50 and 100mg/l in the main plots, magnetic field at 3 levels of control, 10 and 20ms, in the subplots and temperature stress in three levels including 2, 8 and 20°C. It was done on strawberries in subplots. Healthy prepared strawberry fruits were subjected to magnetic treatments and then immersed in hormonal solutions for 2min and after drying, stored for 8 days in different refrigerators at temperatures according to research treatments. The samples were then removed from the refrigerator and transferred to a laboratory to measure various characteristics. The studied traits included: fruit weight, fruit diameter, fruit length, fruit moisture content, titratable acidity, fruit juice pH and vitamin C.

 Results of analysis of variance showed that the simple and triple interactions of treatments on all studied traits were significant. Comparison of the mean triple interaction of gibberellic acid treatment × magnetic field × temperature showed that the highest amount of fruit weight (19.49g), the highest amount of fruit diameter (33.7mm), the highest fruit length (48.62mm), the highest fruit moisture (34.65%) was obtained in the treatment of 50mg/l gibberellic acid, ten Tesla magnetic field and a temperature of eight degrees Celsius. The lowest fruit weight of 10.65 g was obtained in the treatment of non-use of gibberellic acid, non-use of magnetic field and temperature of 20°C. The lowest fruit weight loss of 3.74% was obtained in the treatment of 50 mg/l gibberellic acid, 20 Tesla magnetic field and 2°C. The lowest fruit diameter of 21.52mm was obtained in the treatment of non-consumption of gibberellic acid, absence of magnetic field and temperature of 20°C. The lowest fruit length of 25.63 mm was obtained in the treatment of no gibberellic acid, no magnetic field and a temperature of 20°C. The lowest amount of titratable acidity (0.31%), the lowest pH of fruit juice (4.68) and the highest amount of vitamin C (34.92mg/100 ml) in the treatment of non-use of gibberellic acid, no use of field Magnetic and a temperature of 20°C were obtained. The lowest amount of vitamin C was equal to 20.5mg/100ml in the treatment of no use of gibberellic acid, no use of magnetic field and a temperature of 20°C.High concentrations of gibberellic acid have a beneficial effect on increasing cell division and fruit size. Gibberellic acid increases fruit size and weight due to its effect on increasing cell division in the early stages of fruit development and increasing cell size at late fruit ripening. Magnetic field also affects plant metabolic activity. Fruit volume includes fruit length. It decreases due to the magnetic field. Fruit weight showed a significant positive correlation with fruit diameter, fruit length, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field and a temperature of 8°C.

 Fruit weight showed a significant positive correlation with fruit diameter, fruit height, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field at a temperature of 8°C.