Comprehensive evaluation of heat resistance in 68 Vitis germplasm resources

Temperature is a crucial factor limiting plant growth. Grapevine is frequently subjected to high temperature during its maturation stage, and this seriously influences grape growth and development. Here, we selected 68 grapevine varieties and examined the heat damage index, relative electrolyte leakage, and Fv/Fm after exposure to 50 °C. 'Red Seedless', 'Hong Yuli', 'At Suma', 'Hupei 3#', and 'Tamina' were tolerant to high-temperature stress; however, 'Brazil', 'Shenfeng', 'Gold Finger', 'Heimeixiang', 'Kaiji', and 'Zuijinxiang' varieties were sensitive to high-temperature stress and died after exposure to 50 °C. Our findings provide a valuable insight into resistance breeding programs for grapevine.