Turkish Journal of Botany, cilt.50, sa.2, ss.163-176, 2026 (SCI-Expanded, Scopus, TRDizin)
Rising global temperatures due to climate change threaten optimal strawberry growth and sustainable yields. Limited data exist on the physiological and biochemical responses of strawberry cultivars to high-temperature stress and their tolerance mechanisms. This study evaluated the responses of 21 day-neutral and short-day strawberry cultivars to high-temperature stress and classified their tolerance levels using a novel weighted rating method. Plants were grown in 15-cm plastic pots (3:1:1 garden soil, peat, perlite) under open-field conditions until the 3–4 leaf stage and then transferred to climate chambers. After acclimatization at 25/15 °C (day/night) for 2 weeks, the plants were subjected to increasing temperatures (30/25, 35/25, 40/25, and 45/25 °C) every 48 h, with controls maintained at 25/15 °C. High temperatures significantly reduced relative water content (RWC), total chlorophyll content, and membrane stability index (MSI), while increasing leaf surface temperature, malondialdehyde (MDA), and proline content. Among the cultivars, Portola exhibited the highest RWC, MSI, and proline content; Redlands Hope the highest chlorophyll content; and Fronteras the highest MDA content. Using a new modified weighted rating method based on MSI, proline content, and leaf wilting at 45 °C, the cultivars were classified as tolerant (Albion, Portola, Monterey, Sweet Ann, Osmanlı, Calinda, and Splendor), moderately tolerant (Alba, Asia, Favette, Fortuna, Petaluma, Roxana, Redlands Hope, and San Andreas), or sensitive (Festival, Sabrina, Jive, Tillamook, Amiga, and Fronteras). These findings provide valuable insights for breeding heat-tolerant strawberry varieties, supporting sustainable agriculture in a warming climate.