The Effect of Paclobutrazol and Calcium Prohexadione on Some Vegetative and Reproductive Characteristics of Strawberry (Fragaria × ananassa Duch. cv. Paros)

In order to evaluate the role of paclobutrazol (PBZ) and prohexadione-calcium (ProCa) in reduction of vegetative growth and improvement of reproductive growth of strawberry (cultivar Paros), a 4-replicate completely randomized design was carried out in greenhouse. ProCa in three concentrations of 0, 100 and 150 mg L-1 and PBZ in four concentrations of 0, 60, 90 and 120 mg L-1 were sprayed on the strawberry plants in two stages (four weeks after planting and three weeks after the first stage). The results showed that the application of PBZ, ProCa and also their interaction had a significant effect on plant height, plant fresh weight, petiole length, specific leaf weight, root weight ratio, crown number, fruit number, fruit yield and harvest index. Application of 120 mg L-1 of PBZ without the use of ProCa resulted in the lowest plant height. The interaction of 100 mg L-1 of ProCa and 60 mg L-1 PBZ resulted in the highest number of flowers and crowns. The use of these retardants did not have a significant effect on fruit weight. The effect of ProCa and its interaction with PBZ was significant on the number of flowers and the interaction of PBZ and ProCa was significant on fruit set. Treatment with 100 mg L-1 ProCa without PBZ was the most effective treatment on increasing fruit set. In general, the results showed that the use of retardants reduced the vegetative growth and increased reproductive growth of the Paros strawberry genotype. The concentration of 100 mg L-1 ProCa and 60 mg L-1 PBZ was the most effective treatment for increase in reproductive growth of the examined strawberry cultivar.