Improvement of ‘Nova’ mandarin productivity

physiological aspects and agricultural practices

Abstract

Under Uruguayan southern conditions ‘Nova’ mandarin behaves as a low yielding cultivar. During the first years after planting, it shows high flowering intensity, low leaf:flower ratio and extremely low fruit set. To improve its productivity, different cultural practices were evaluated over two experiments. Flowering intensity, pattern of fruitlet abscission, final fruit set and yield were measured. Gibberelic acid (GA₃, 40 mg L^-1) sprayed during winter period (June), significantly reduced flowering intensity due to a reduction in the sprouting intensity accompanied by an increase in the proportion of leafy shoots. Although GA₃ applied at this stage increased final fruit set, it did not significantly improve yield. GA₃ applied at full bloom (50 mg L^-1), delayed fruitlet abscission, but had no effect on final fruit set, and reduced fruit size. Girdling carried out 30 days after full bloom did not improve fruit set in the performed experiment. However, when combined with a winter GA₃, application, increased final fruit set and yield. Therefore, we conclude that this combined practice is the most suitable to enhance ‘Nova’ mandarin productivity.