Evaluation of apple cultivars and hybrids in a fruit nursery

Abstract

The study was conducted in the fruit nursery of the Institute of Agriculture - Kyustendil during a two-year period (2011-2012). The main aim of this study was to check the quality of nursery trees of 24 introduced apple cultivars and hybrids, grafted on ‘MM 106’ rootstock. The rootstocks were budded at the height of 15 cm from the ground by chip budding on July 28. During the research, the following indicators were measured: percentage of developed buds, growth dynamics of the nursery trees, the number of plants with sylleptic shoots, the height and the thickness of nursery trees and at the end of the growing season. Percentage of standard and non-standard trees was recorded according to the norms of the Bulgarian State Standard. It was established that the ‘Hybrid No 6’ and ‘Rubin’ had the highest percentage of developed buds, while ‘Red General’ and ‘Pinova’ had the lowest values. ‘Remo’, ‘Free Redstar’, ‘Melfree’, ‘Gold Millennium’, ‘Reandra’, ‘Primera’, ‘Hybrid No 6’ and ‘Red General’ had a stronger growth and ‘Brina’, ‘Pacific Rose’, ‘Longlu’, ‘Honglu’, the hybrid ‘Pinova’ × ‘Fuji’, ‘Goldrush’, ‘Yanga 1’ and ‘Renora’ had weaker growth, compared to the standard (‘Granny Smith’) and the rest of cultivars. Cultivars ‘Granny Smith’, ‘Longlu’, ‘Yanga’ and the ‘Pacific Rose’ showed a tendency to form sylleptic shoots in the nursery. The highest percentage of standard planting material was obtained from ‘Hybrid No 6’, ‘Granny Smith’ and ‘Rubin’ and the lowest from ‘Brina’, ‘Pacific Rose’ and the hybrid ‘Pinova’ × ‘Fuji’.