Clonal selection in ‘Tombul’ hazelnut: Preliminary results

Abstract

There are 18 registered hazelnut cultivars grown in Turkey. Among these, ‘Tombul’ has the highest quality. Some morphological variations have been observed among ‘Tombul’ plants, ocaks and orchards. A research project was carried out between 2007 and 2012 to identify superior ‘Tombul’ clones in Giresun and Trabzon provinces where this cultivar is widespread and the ecological conditions are ideal for hazelnut. A total of 380 ‘Tombul’ plants were evaluated for three years, and 29 of them were selected based on yield and quality. Before proceeding with replicated trials the identity of these selections was verified. Molecular analysis using AFLP and SSR markers showed that 14 selections were found to be genetically different (clones) from the standard ‘Tombul’. These clones were propagated in 2013 and a replicated trial was established in 2014. Phenological observations and pomological analyses were made in 2015 and 2016. The cumulative yield was 82.2 g plant-1 in standard ‘Tombul’ while higher cumulative yields were recorded in selections of 61Ç17 (181.2 g), 28G13 (134.8 g), 28P01 (118.3 g), 28M15 (108.1 g), 61V25 (107.3 g) and 28K16 (86.7g). Differences were also noted in nut and kernel sizes (15.4-16.8 and 11.8-14.1 mm, respectively) and weights (1.65-1.95 and 0.89-1.07 g, respectively), shell thickness (0.91-1.02 mm), percent kernel (50.8-55.7%), internal cavity diameter (1.62-2.35 mm), ratio of good kernels (82.5-100%), and in plant characteristics such as plant height (165-211 cm), stem diameter (31.7-38.6 mm) and number of suckers (17.9 to 29.2). Evaluation of the selections will continue for several more years. © 2018 International Society for Horticultural Science. All Rights Reserved.