Improving Fruit Set, Yield and Fruit Quality of Date Palm (Phoenix dactylifera, L. cv. Mnifi) Through Bunch Spray With Boron and Zinc

Fertilization is one of the most important cultural practices in date palm orchards. Spraying micro-nutrients has an important role in fruit set, fruit retention, development, improved total yield, and fruit characteristics. The present study was conducted during the two successive seasons, 2011 and 2012, in order to investigate the effect of bunches sprayed with boron and/or zinc on fruit set, yield, and fruit quality of 10-year-old "Mnifi" date palm. Bunches were pollinated by placing 10 "Meghal" fresh male strands among female clusters during both seasons. Nine spraying treatments were performed twice; 2 h before pollination and 4 weeks after pollination. Results of the two seasons indicated that application of 1500 ppm boron +300 ppm zinc (B-1 + Zn-1) increased total yield/ palm, fruit weight and volume, flesh weight, soluble solids content (SSC), and total and reducing sugars. Fruit set and titratable acidity were improved with spraying of 1500 ppm boron (B-1). Fruit dimensions and moisture content increased with B-1 treatment in the first season and B-1 + Zn-1 treatment in the second season. Application of boric acid alone (1500 ppm) or combined with zinc sulphate (300 ppm) to get a positive effect on fruit set, total yield, and fruit quality of "Mnifi" date palm could be recommended.