ISHS Acta Horticulturae 591: III International Symposium on Pistachios and Almonds
EFFECTIVENESS OF BORON AND ZINC FOLIAR SPRAYS ON FRUIT SETTING OF TWO ALMOND CULTIVARS |
| Authors: | C. Sotomayor, H. Silva, J. Castro |
| Keywords: | Prunus dulcis, almonds, boron, zinc, fruit set, foliar sprays. |
| Abstract:
Fruit set is crucial in almond trees (Prunus dulcis) and it has been proven that micronutrients, zinc (Zn) and especially boron (B), have a significant impact on fruit set, as well as on fruitlet abscission. In several fruit trees it has been reported that even foliar spraying of one or both elements has improved productivity. As far as almond trees are concerned there is very little information in this respect; therefore 2 experiments were carried out with almond trees cv. 'Nonpareil' and 'Carmel'. In the first experiment 'Nonpareil' trees were sprayed at full blossom with boric acid at 0.2%, Zn-50 at 0.3% and with the combination of these micronutrients, compared with a non-sprayed control. Fruit set of the latter was 23.4%, similar to the B treatment (27.7%) and Zn (22.2%). However the B + Zn combination produced a significantly higher fruit set (38.1%). In the second experiment, trees of 'Nonpareil' and 'Carmel' were sprayed with boric acid at 0.15% and 0.30%, both post harvest and during the blossom period, in order to determine the possible influence of the time of spraying and of 2 doses on fruit set. In 'Nonpareil', B at 0.15% at blossom produced a 20.2% fruit set and B at 0.30% at post-harvest produced a fruit set of 19.9%, similar to the control with 15.5%. B at 0.30% at bloom had only 10.7% of fruit set, significantly lower than the first two. In 'Carmel' the best result of fruit set was with B 0.15% at post-harvest (27.8%), significantly higher than the control (20.9%). B 0.15% at bloom with 23.1% and B 0.30% post-harvest with 21.7% were similar to the previous ones. The least effective treatment was B 0.30% at bloom with 12.3% fruit set. None of the experiments showed any difference in the foliage contents of B or Zn nor in the final seed weight as a result of treatments. | |
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