ABSTRACT

Earlier research has shown a strong correlation between low yields and high temperatures during boll filling. Preliminary research comparing boll growth and yields in contrasting environments (Arkansas and Greece) indicated that an 8ºC higher night temperature during boll development in Arkansas may be a major contributory factor to lower yields. A field experiment was designed using plastic covering over replicated plots at night and heaters or air conditioners, to rise or lower, night temperature compared to the control. Results indicated that high night temperature decreased boll weight, with fiber weight per seed being the main yield component affected. There was no significant effect on respiration or photosynthesis. The one week temperature treatment period was too short and allowed sufficient time for compensation. The study will be repeated in 2003 with some modifications.