effects of putrescine and potassium nitrate spray on improvement of vegetative and reproductive growth of quince (cydonia oblonga cv. esfahan) fruits

today, hormones and nutrients are used in order to improve vegetative and reproductive growth of many agricultural products in the world. the purpose of this study, was to increase fruit set, fruit weight, and finally, increase of yield along with improvement of vegetative growth with putrescine treatments (0, 0.01, 0.001m) and potassium nitrate (0, 2 and 4%) of quince (cydonia oblonga cv. esfahan) fruits. trees were sprayed at two stages of bud tip green and full bloom, as a split-factorial experiment in a randomized complete block design with four replications. comparison of means showed 0.01 m putrescine treatment alone or in combintion with potassium nitrate (4 and 2%) showed a significant effect on increasing percent of fruit set, average fruit weight and yield. putrescine and potassium nitrate treatments also could increase leaf area, leaf chlorophyll index and the length of current season shoots compared to the control. results showed that, treatments with higher concentrations of putrescine and potassium nitrate as well as their combination had the best effect on measured parameters. in addition, spraying in green tip stage was the best timing to improve the measured characteristics.