Effects of elevated temperatures at different fruit development stages on apricot ( Prunus armeniaca L.) growth and quality

Abstract

This study evaluates the potential impacts of warmer temperature conditions on apricot ( Prunus armeniaca L.) production and fruit quality, with particular emphasis on whether key commercial traits decline under heat stress. Warmer temperature conditions were simulated in a commercial orchard by covering individual trees with a thin, transparent polyethylene film. We examined the effect of cover timing (early cover, late cover, and uncovered control) on leaf photosynthesis, yield, and a range of fruit quality traits in the cultivar ‘LadyCot’. From fruit set to harvest, the plastic cover increased daily mean and maximum temperatures by approximately 1.7 °C and 3.9 °C, respectively, with more than twice hours above 30 °C compared to the control. Elevated temperatures did not accelerate ripening and control fruits matured 3–4 days earlier than those grown under the plastic cover. Plastic-covered trees produced smaller fruits (around 55 g) compared with the control (67.9 g), suggesting that heat stress reduced cell division and expansion. Several fruit quality parameters were also affected. Fruits under plastic cover were firmer, had lower soluble solids content, and developed less intense external coloration, while flesh colour remained unaffected. Overall, the results indicate that although short-term plastic cover can enhance early-season photosynthetic activity, prolonged exposure under warm conditions reduces fruit size and compromises fruit quality, therefore limiting its potential benefits, particularly for late-ripening cultivars. These preliminary findings suggest that projected temperature increases under future climate scenarios may pose a significant risk to apricot yield and quality in warm growing regions, highlighting the need for further research.