Efficiency of Fruitlet Thinning Apple „Golden Reinders” by use Naphthylacetamide Acid (NAD)

Abstract

Thinning the apple crop during the post bloom periodis absolutely essential to ensure large fruit size, superior fruit quality, andreliable annual cropping. To evaluate the effectiveness of thinning agent onbase of naphthylacetamide acid (NAD) in reducing fruit set in Golden Reindersapple trees. The experimental plot is placedin the orchard “Dacfruct” Ltd. founded in 2006 with trees of a „knip boom” canopytype. The study subject of theexperience was Golden Reinders apple variety grafted on M 9 weak vigorrootstock. The trees were trained as slender spindles. The distance ofplantation is 3,5 x 1,2 m.The agent tested were NAD, (preparation Geramid New). Thepreparation was sprayed on the trees either one time (when fallen 80% of petals +2-3 days), or twice (the secondspraying was repeated at the dimension of central fruits 6 mm in diameter). Theresearch was conducted during the period of 2011 year. During the research, itwas studied the number of blossom clustersbefore thinning degree, fruit at harvest time (number per tree, number per 100flower clusters and number per cm2 TCSA), yield, mean fruit weight, average fruit diameter, sizeclasses based on their diameter and the number of pygmy fruits. It wasestablished that, the good effect of thinning was noticed after one spray withpreparation Geramid New. The single treatment has a significant affect onyield, mean fruit weight and positively influenced fruit size, the distributionof apples in size classes.