Effect of foliar application of urea and potassium chloride on flowering characters and concentration of auxins and gibberellins in flowers and fruits of jujube Ziziphus mauritiana Lam. cv. Tufahi

Abstract

The present study was conducted on 12 years old jujube trees Ziziphus maurtitiana Lam., cv. Tufahi which were grown in a private orchard situated at Al-Hartha District. Basrah Governorate during the growing season of 2009 to investigate effects of spraying urea fertilizer at concentrations of 0%, 1% and 2% and potassium chloride fertilizer at concentrations of 0%, 0.5% and 1% and their combinations on flowering characters and concentrations of auxins and gibberellins like substances in flowers and fruits. The trees were sprayed three times on 15th and 30th August and 15th September 2009. Results showed that treatment of 2% urea recorded significant increases in flowering shoot length , number of leaves per flowering shoot, number of flower per inflorescence and concentration of gibberellins like substances in fruit. Treatment of 1% urea gave significant increases in fruit set and concentration of auxins like substances in fruit whereas treatment of 0% urea recorded significant increase in flower drop percentage. Treatment of 1% kCl recorded significant increases in flowering shoot length, number of leaves and inflorescences per flowering shoot, concentration of auxins and gibberellins like substances in fruit. The combination treatments of 2% urea and 0% kCl gave significant increases in flowering shoot length and number of flowers per inflorescence whereas treatment of 2% urea and 1% kcl significantly increased number of inflorescences per flowering shoot and concentration of gibberellins like substances in fruit. Treatment of 0% urea and 1% kCl significantly increased number of leaves per flowering shoot and concentration of auxins like substances in fruit whereas treatment of 1% urea and 0.5% kCl increased percentage of fruit set significantly. Treatment of 0% urea and 0% kCl had the highest percentage of flower drop. Anthesis stage had significant increase in concentration of auxins like substances in fruit whereas period of one week after fruit set had significant increase in concentration of gibberellins like substances in fruit. The tri-combination of 0% urea and 1% kCl and period of one week after fruit set had the highest concentration of auxins like substances in fruit whereas that of 2% urea and 1%kCl and period of one week after fruit set recorded the highest concentration of gibberellins like substances in fruit.