Heat stress detection in tomato under different irrigation treatments

S. Takács, Z. Pék, T. Bıró, L. Helyes

Research output: Contribution to journalArticle


Processing tomato (Solanum lycopersicum) production is growing continuously worldwide, as well as in Hungary. This vegetable cannot be cultivated without irrigation except in small regions of the main production area. Water savings can be achieved more effectively if we have a better understanding of how heat stress affects the given species or hybrid. To understand the impact of heat stress in processing tomato, an open field experiment was conducted in Szarvas with ‘UG812J’ F1. The weather was adequate for detecting heat stress in July of 2017. Plants under two different irrigation levels, 100% of potential evapotranspiration (ET) and 50% of ET (D) were compared with control (K). Raytek Raynger II infrared remote thermometer and a FLIR One for Android thermal cam were used for the measurements. Two heat stress indices were calculated from the gathered canopy temperature data, stress degree day - SDD (Tleaf - Tair) and crop water stress index - CWSI (Tleaf - Twet)/(Tdry - Twet), respectively. For the CWSI, wet and dry reference surfaces were used to simulate a fully transpiring and a non-transpiring leaf. Statistical analysis showed that in the case of SDD computed from thermometer data and CWSI computed from thermal cam data, all the three treatments with different water supply were distinguished (P<0.05). Only the rainfed control and the two irrigated treatments were separated by the post-hoc test in the matter of CWSI calculated from thermometer data and SDD calculated from thermal cam data (P<0.05). Moderately strong coherence was found only in one case when a linear model was fitted to soil moisture and heat stress data. Soil moisture affected tomato’s heat stress level according to the linear regression. Highest R2-value was obtained with SDD data (R 2 =0.53; P=0.04). Other linear models fitted to the rest of the data could not provide any strong connections.

Original languageEnglish
Pages (from-to)47-52
Number of pages6
JournalActa Horticulturae
Publication statusPublished - Jan 1 2019



  • CWSI
  • Infrared thermometer
  • Precision irrigation
  • SDD
  • Solanum lycopersicum
  • Thermal cam
  • Water stress

ASJC Scopus subject areas

  • Horticulture

Cite this