ملک حسین شهریاری

Strawberry is a small fruit crop (Fragaria x ananassa Duch) native to temperate zone but grown worldwide due to its characteristics. This fruit contains significant amounts of minerals, vitamins and essential amino acids, antioxidant compounds and flavonoids. Currently, greenhouse strawberry production using hydroponic systems are increasing. The two main objectives in growing strawberry are to increase production and enhance the quality. However, there are many problems exist such as low yield and quality, sensitivity to unfavorable greenhouse conditions i.e. temperature, humidity, light intensity, nutrients, drought and high salinity that effect on growth and yield of plant. The objective of the present study was to investigate the impact of foliar application of putrescine and humic acid on the vegetative growth, yield and quality of strawberry plant in soilless culture. The experiment based on completely randomized block design included foliar application of five putrescine levels of 0, 0.5, 1, 2, 3, 4 mM and 4 humic acid levels of 0, 10, 20 and 40 mgl-1. A randomized complete block design with 20 treatments and 3 blocks (replicates) for each treatment and each replication consisted of 2 pots (each pot containing one plant) and hence a total of 120 plants were used. Five times of foliar spray of putrescine were applied 3 and 5 weeks after transplanting, at onset of flowering and first and third week after fruit setting. Plant vegetative and reproductive traits and fruit characteristic were measured. The results showed that foliar application of putrescine significantly increased the number of fruits per plant, yield, and total soluble solids of fruit and while it showed non-significant decrease in the number of days to first harvest of fruits per plant. Humic acid increased fresh and dry weights of shoot but reduced fruit titrable acidity both insignificantly. The interaction of the two factors affected the number of days to first harvest of fruits per plant. Th