The use of the photosynthesis inhibitor metamitron, and the use of temporary artificial shading as two methods of fruitlet thinning, were evaluated in 2006 and 2008 in apple trees 'Gala Must'. The use of these 2 methods used separately, were expected to induce a temporary decrease in photosynthetic intensity which would strengthen the competition between the fruitlets. This process would then lead to the abscission of the weaker ones. For this purpose, metamitron (preparation Goltix 700SC) was used. A dose of 350 mg/l was sprayed on the trees either one time (when fruitlets were 68 mm in diameter), or twice (the second spraying was repeated 6 days later on fruitlets 10-14 mm in diameter). Another group of trees was covered for 5 to 14 days with polipropylene material causing about a 70% reduction of light. In 2006, only the double metamitron treatment caused significant reduction of fruit set (comparable to hand thinning). This resulted in an increase in the fruit size and yield of marketable (> 70 mm) apples without negative effect on the total yield, 'internal quality' and red colour of the apples. In 2008, the good effect of thinning was noticed after one spray with metamitron, while a double treatment caused over-thinning. The single treatment with metamitron positively influenced fruit size, the distribution of apples in size classes, and yield of apples with diameters of > 70 mm. Comparable thinning was recorded in trees artificially shaded for 10 days; fruitlets were 6 to 14 mm in diameter. The uniform distribution of fruits, which were homogenous in size in the canopy of the trees, proved that both methods of thinning have high selectivity.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.