Heat susceptibility evaluation among 100 mango (Mangifera indica) genotypes: a comparative study on leaf cell membrane stability at high temperatures using electrolyte leakage.

Abstract

High-temperature stress induced by global warming can hinder the production of commercial cultivars in mangoes (Mangifera indica L.). Selecting cultivars with high-temperature tolerance is essential. We evaluated damage to leaf cell membranes as an indicator of high-temperature tolerance in mangoes. An evaluation method using leaf-electrolyte leakage was established by comparing the temperature responses of several genotypes, and then applied to 100 genotypes, including major cultivars worldwide. Genotypic differences in high-temperature tolerance were verified based on the climate of selection and production areas. Logistic regression analysis was performed on datasets from two different years for each genotype, with temperature (40-55 °C) as the explanatory variable, and the calculated Injury Index as the target variable. The obtained regression equations were highly accurate (R2 > 0.9; RMSE < 10) for each genotype and year. Furthermore, a strong positive correlation (Spearman's rank correlation coefficient > 0.8) was obtained between the pair of temperature conditions and the maximum curvature on the regression curve (Cmax) for two different years for each genotype, confirming the validity of the evaluation method. Up to ≈ 6 °C genotypic difference was observed in the mean Cmax values. Cultivars from warm and humid Southeast Asia tended to have a higher cell membrane tolerance than those from dry India. Florida cultivars, mostly pedigreed from Southeast Asia and India, were widely allocated from high to low. We ranked 100 mango genotypes based on the high-temperature tolerance of leaf cell membranes, demonstrating reasonable consistency with the climatic conditions of their selection and production areas.