USING PLANT BIOREGULATORS TO IMPROVE PRODUCTION AND FRUIT QUALITY OF STRAWBERRY

Hydroponic production of strawberry in greenhouse conditions is ever increasing; however there are still problems such as low yield, poor fruit quality and sensitivity to unfavorable indoor conditions. Use of plant bioregulators in combination with essential elements would not only alleviate these problems but would also have a positive impact on overall growth of plants. Three separated experiments were carried out on strawberry cultivars to assess the effect of salicylic acid (SA), spermidine (Spd), putrescine (Put) and manganese sulfate on vegetative and reproductive growth of strawberry plants. In all researches daughter-rooted plants were potted in plastic pots filled with 1:1 peat moss and perlite, grown in greenhouse, and after their establishment foliar application of treatments was done. In experiment one, the effect of 1, 2 and 3 mM of SA on ‘Pajaro’ was evaluated. Results showed that 2 mM of SA increased total yield, number of fruits and ascorbic acid concentration. Impact of Spd and Put on ‘Paros’ and ‘Selva’ cultivars was investigated in a second study where results indicated that Spd increased chlorophyll content of both cultivars whereas Put decreased it. Polyamines spray caused an increase in diameter and weight of primary and secondary fruits. In the third investigation, the influence of manganese sulfate at two concentrations (1.5 and 3 g L^-1) on ‘Paros’ strawberry was studied: 1.5 g L^-1 of manganese sulfate increased number of fruits and vitamin C concentration. So, bioregulators and essential elements have the potential to manipulate growth aspects and therefore might be used to improve the quality and quantity of production, costs and unfavorable side effects should be taken into consideration when recommendations are made. Local studies on local cultivars may be helpful.