The effects of different bioregulators on salinity tolerance levels of strawberries grown in soilless culture conditions

Drought, salinity, etc. abiotic stress factors such as soil and soilless culture are among the most common agricultural problems in recent years. In particular, salinity stress affects the growth and development of plants and causes yield and quality losses. Strawberry is in the category of plants sensitive to salt, the plant responds quickly to high salinity stress and stress factors can cause irreversible damage. In addition, in soilless strawberry cultivation, the use of growing media used as an alternative to soil in limited and restricted volumes both accelerates and increases the harmful effects of salinity stress. For these reasons, in this agricultural technique, studies on externally applied preparations in order to take quick and effective measures against the salinity problem attract attention. In this study, two different biostimulants (Control, Fitomare, Comcat) in strawberries grown in greenhouse conditions, in cocopeat growing media, at two different EC levels (1.5 dS/m and 2.25 dS/m), were determined morpho-physiologically (crown diameter, number of crown, number of leaves, number of necrotic leaves, chlorophyll index, leaf temperature, , membrane damage index, leaf area index, leaf tip burn, wilt scale), phenological (first bloom, first harvest), pomological (fruit weight, solid soluble matter, firmness, pH, EC, fruit color L, C*, h◦) and their effects on yield and end-of vegetation characteristics (crown and leaf fresh and dry weight, root fresh and dry weight) were investigated. As a result of the research, the first flowering time of the strawberries grown in both control and high salinity conditions was at the beginning of December, the first harvesting time was at the end of January, and there was no difference between bioregulator applications. From January to May, rapid changes were seen in all the morpho physiological features examined. Especially in January, February and March, it was seen that both bioregulator applications tested had a positive effect on the crown diameter and crown number compared to the control applications. No necrotic leaf lesions were observed in January, February and March, and these symptoms started in April and May. In particular, in high salinity conditions, it was observed that both bioregulator applications in April decreased the number of necrotic leaves compared to the control. The relative water content of the leaves showed a decrease depending on the months, and this decrease was observed more in high salinity conditions. In research, it was observed that bioregulator applications under high salinity conditions reduced leaf tip burn. In plants grown in high salinity conditions, the lowest yield was observed in May, and no difference was determined between bioregulators in terms of yield. On the other hand, the firmness of the fruit was found to be more advantageous in the Comcat application than in other applications, both in control and high salinity conditions. As a result of our research findings, it has been shown that bioregulator applications are advantageous in terms of plant growth and development both in control and high salinity conditions. Especially in plants grown in high salinity conditions, bioregulator applications have shown that they can increase plant tolerance by delaying the negative effects of salinity.