DETERMINATION OF TOLERANCE TO HIGH TEMPERATURE STRESS IN SOME TEMPERATE CLIMATE FRUIT VARIETIES

In recent years, global climate change has increasingly disrupted optimal growing conditions for plants, leading to a decline in agricultural productivity. Rising air temperatures, in particular, induce heat stress in plants, resulting in significant economic losses. Consequently, the identification and utilization of ecologically well-adapted species and cultivars have become critically important. In this context, understanding the responses of different plant species and their cultivars to high-temperature stress is essential. This study was conducted on the experimental fields of Eskişehir Osmangazi University, Faculty of Agriculture, and aimed to evaluate the heat stress tolerance of various fruit species and cultivars. The plant material included plum cultivars (Angeleno, Black Beauty, Black Amber, Black Diamond, Formosa, Fortune, Friar), a sour cherry genotype and cherry cultivars (0900 Ziraat, Early Burlat, Kordia, Regina, Starksgold, Sweetheart, and Prunus mahaleb), apple cultivars (Golden Delicious, Pink Lady, Jersey Mac, Williams Pride, Fuji, Granny Smith, Mondial Gala, Red Summer, Vista Bella), and pear cultivars (Santa Maria, Williams, Ankara, Kiefer, Magness, Moonglow, Kaiser Alexandre, Nashi, Conference, Akça Limon, Bursa, Ekşi, Taş). The results revealed significant differences in heat stress tolerance both among species and among cultivars within certain species. Among cherry cultivars, ‘Kordia’ exhibited superior tolerance to high temperatures, while among pear cultivars, ‘Akça’ was identified as the most heat-tolerant. In contrast, no significant differences were observed among the evaluated plum and apple cultivars. When species were ranked according to their overall heat stress tolerance, from most resistant to most sensitive, the order was determined as follows: sour cherry, sweet cherry, pear, plum, mahaleb, and apple.