The effect of night temperature on greenhouse grown tomato yields in warm climates

• Published in: Agricultural and forest meteorology Vol. 92; no. 3; pp. 191 - 202
• Main Authors: Willits, D.H, Peet, M.M
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 16.10.1998; Oxford Elsevier; New York, NY
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; CROP YIELD; ESTRES TERMICO; FRUCTIFICACION; FRUCTIFICATION; FRUITING; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Heat stress; High temperatures; LYCOPERSICON ESCULENTUM; Lycopersicon esculentum Mill; Protected cultivation; RENDEMENT DES CULTURES; RENDIMIENTO DE CULTIVOS; Soilless cultures. Protected cultivation; STRESS THERMIQUE; TEMPERATURA; TEMPERATURE; Temperature stress; THERMAL STRESS; Tomato; Yield; North Carolina; United States; North America; America; Yield; Heat stress; Temperature stress; Tomato; High temperatures; Lycopersicon esculentum Mill; Heat treatment; Production quality; Horticulture; Temperature effect; Protected cultivation; Hot climate; Seasonal variation; Dicotyledones; Angiospermae; Lycopersicon esculentum; Cooling treatment; Solanaceae; Nocturnal variation; Phytoclimate; Air conditioning; Cooling; Thermal factor; Agroclimatology; Stress; Vegetable crop; Spermatophyta; Greenhouse; Night temperature; Temperature fluctuation; Fructification
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/S0168-1923(98)00089-6

Data from six seasons of night cooling experiments conducted at north Carolina State University were analyzed to determine the effect of night temperature on the yield of tomato. Each season contained at least one treatment where night temperatures in one greenhouse were kept below 20°C, using air conditioning, and one treatment where night temperatures in a separate greenhouse were essentially the same as those outside. Two seasons included additional treatments where night cooling took place only from 01:00 hours until dawn. Regression analysis indicated a strong dependence of yield on the night temperature during fruitset when the warm treatment temperature exceeded 21°C. Total fruit numbers were as much as 39% higher, and total weights as much as 53% higher, than that observed in the warmer treatment. The effect on fruit quality was even greater, with No. 1 number and No. 1 weight increases as high as 85% and 106%, respectively, as the warm treatment approached 24°C. Regression also suggested the possibility of secondary effects: (1) night temperature reductions over the whole season (as opposed to only during fruit set) and higher night time relative humidities in the warm treatment during fruitset were independently predicted to decrease the quality advantage in the cool treatment(s); (2) higher levels of irradiance were predicted to increase the weight advantage in the cool treatment(s).