Spring late frost resistance of selected wild apricot genotypes (Prunus armeniaca L.) from Cappadocia region, Turkey

Abstract

Spring late frost is the most important problem in apricot growing. One of the effective and long-lasting solutions is the development of genotypes with frost resistance as well as late flowering. In this study, low temperature resistance of 36 wild apricots (Prunus armeniaca L.), selected for their survival after severe spring late frosts in their natural environments among the rich genetic resources of Cappadocia (Nevşehir-Turkey) was determined by artificial freezing tests in controlled conditions. Apricot cultivars of Hacıhaliloğlu, Kabaaşı, Hasanbey, Aprikoz and Levent were used as control. Low temperatures were applied to flower buds, flowers and young fruits at red calyx (–8 °C), balloon (–8 °C), full flowering (–4 °C), petal fall (–3 °C) and young fruit (–3 °C) stages for 2 hours. The cooling rate was 2 °C h−1 with linear decline. Survival rates (%) of female organs in flowers and seeds in young fruits were determined by visual assesments, and by electrical conductivity (μS.cm−1) measurements which is an indication of ion leakage from damaged tissues in genotypes. The results showed that resistance of the wild apricots to low temperatures varied by developmental stage. Overall, most of the genotypes had higher survival rates than the standard apricot cultivars. However, genotypes # 24 and 45 exhibited high viability rates (68.3%<) and low EC values (<30.1%) at many stages of development in both years, and were considered resistant to spring late frosts. Hierarchical Cluster Analysis with the genotypes’ survival rate (%) and electrical conductivity (μS cm−1) data together without discrimination of growth stage placed these two genotypes in the same group.