Effect of Temperature Treatment on Peanut Vegetative and Fruit Growth1

Abstract

Abstract Two studies were conducted in growth chambers to evaluate the effects of temperature on the vegetative and reproductive growth phases of peanuts (Arachis hypogaea L., cv. Florigiant). Temperature regimes in the first study ranged from 34/30 to 18/14°C day/night and in the second from 34/30 to 22/18°C. The experiments were conducted for 61 and 110 days, respectively. In the first study, the plants were kept vegetative by clipping the pegs. Dry weights of leaflets, petioles and stems, leaf area, and number of flowers were measured. The same measurements plus fruit weights were made in the second study. Early growth, as determined by accumulation of top dry weight, was optimum at a weighted mean temperature of 27.5°C and essentially no growth occurred at 15.5°C. When plants were grown at the optimum temperature for four weeks and then subjected to different temperatures, the treatments had much less effect on top weight during subsequent growth and the optimum temperature decreased somewhat relative to that for early growth. Total fruit weight and individual pod weight were greatest at 23.5°C. Also, the rate of increase in pod weight was greatest at 23.5°C. During early growth the optimum temperatures for development of leaf area and for rate of flowering were above 28°C while in later stages the optimum for rate of flowering decreased to about 26°C.