Influence of 1-naphthylacetic acid on pre-harvest fruit drop and quality of Idared apples

Abstract

The research was carried out during 2016, in the intensive apple orchard founded near the village of Păulești, Călărași district, in the autumn of 2006 at the company S.R.L."Codru ST". The object of the study were trees of the Idared variety grafted on rootstock M9. The trees were trained on the improved super spindle crown. Plant spasing is 3.5 x 1.2 m. The growth regulator Obsthormon 24a plays an important role in preventing preharvest fruit drop in the intensive apple plantations of different varieties, to maintain physiological balance in the plant and to keep as much as possible fruit in the crown at harvest time. To achieve this aim, the following variants were studied: 1. Without treatment (control); 2. Obsthormon 24a - 200 ml/ha; 3. Obsthormon 24a - 300 ml/ha; 4. Obsthormon 24a - 400 ml/ha; 5. Obsthormon 24a - 500 ml/ha; 6. Obsthormon 24a - 200+200 ml/ha; 7. Obsthormon 24a - 200+300 ml/ha. Investigations carried out show that the growth regulator Obsthormon 24a can be included in the technological system for the prevention of premature fruit drop before harvesting of Idared apple production when the treatment was carried out in two steps at the dose 200+300 ml/ha. The first treatment to be applied in the first decade of July, when bud differentiation starts on apple, and the next one 15 days before harvest.