Efficiency of fruitlet thinning apple „Golden Reinders” by use Naphthylacetamide acid (NAD)

Abstract

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