Exploiting Genetic Variation for Heat Stress Tolerance in Tomato Conference Paper uri icon


  • Tomato production is vulnerable to extreme heat during the spring-summer cropping season, exacerbated by a lack of superior genetic materials that can perform well in such environments. The selection of resilient varieties through an improved understanding of morpho-physio-biochemical traits is imperative to sustain tomato production under high-temperature conditions. Thus, this study was conducted to determine heat-tolerant tomato varieties through an improved understanding of their physio-biochemical basis of heat-tolerance. The first study was conducted in three stages to select heat-tolerant varieties under persistent heat-stress conditions in controlled and open-field conditions. In the first stage, varieties were screened based on yield responses. Then, eighteen varieties were chosen and exposed to control (green-house: 26/20 ) and constant heat-stress (growth-chamber: 34/24 ) conditions. The last stage was executed in an open field with twenty-four varieties selected from the first two experiments. Plant morphology and physio-biochemistry were assessed under different environments. From this study, we concluded that heat-tolerant genotypes selected through chlorophyll fluorescence measurements and heat injury index rank in controlled heat-stress conditions exhibited heat-tolerance in open-field conditions as well. Electrolyte leakage and heat injury index distinguished the varieties best in open-field conditions as the plants with low electrolyte leakage and heat injury index had higher marketable yield. Heat Master, New Girl, HM-1823, Rally, Valley Girl, Celebrity, and Tribeca were selected as high heat-tolerant varieties. In the second study, selected ten tomato varieties were exposed to three temperature conditions (26/18 as control, 38/28 for seven days as heat-stress, and 40 for 7 hours as heat-shock), and plant physio-biochemical traits were assessed. Electrolyte leakage, malondialdehyde content, and heat injury index most efficiently discriminated the varieties under both heat-stress and heat-shock conditions. Heat Master under heat-shock and Celebrity, Heat Master, Valley Girl, New Girl, and Picus under heat-stress conditions were identified as the most heat-tolerant varieties. Celebrity, Heat Master, Valley Girl, and New Girl were established as heat-tolerant under all environments in the study. Adopting these promising varieties could potentially enhance tomato production in the areas prone to extreme temperatures during the cropping period.

published proceedings


author list (cited authors)

  • Bhattarai, S., & Leskovar, D. I.

complete list of authors

  • Bhattarai, Samikshya||Leskovar, Daniel I

publication date

  • November 2020