Boosting Resilience and Efficiency of Tomato Fields to Heat Stress Tolerance Using Cytokinin (6-Benzylaminopurine)

Heat stress is one of the most critical environmental abiotic stresses that can negatively affect plant growth. This article investigates the role of a plant growth promoter (Benzylaminopurine) in tomato fields in regard to its ability to withstand high-temperature conditions resulting from greenhouse gas emissions and climate changes. Three genetically different tomato cultivars (Castlerock, GS 12-F1, and Fayrouz F1) were sprayed with 2% 6-Benzylaminopurine (BAP) at 300 and 600 ppm; then, growth and yield components, physio-biochemical characteristics, and antioxidant enzyme activities were determined. The results showed that the highest BAP concentration (600 ppm) enhanced the ability of tomato plants to withstand high temperatures and the maximum dose of BAP improved chlorophyll (71.7 spad units) in GS 12 leaves, while the same dose enhanced proline contents (24.91 mg/100g FW), total antioxidants (83.35 µmol Trolox/g dw), total phenolics (20.99 mg/g dw), Superoxide dismutase (33.74 U/g), peroxidase (46.30 U/g), and polyphenol oxidase (64.10 U/g) in Fayrouz F1 leaves. Application BAP on tomatoes moderately improved fruit quality, such as ascorbic acid and maturity degree, while BAP applications reduced TSS and acidity. In this investigation, taste index was not affected by Benzylaminopurine application but by tomato genotype. The highest number of fruits/plant (45.7), fruit yield/plant (3.98 kg), and total yield (103 tons/ha) were obtained from the GS 12 genotype.