The effect of temperature at early flowering on the growth and development of peanuts (Arachis hypogaea)

Abstract

The effect of a number of temperature treatments on peanuts, applied during a 12-day period soon after the onset of flowering, was studied in a phytotron on a Spanish type variety, Spantex. The treatments were 30/20, 30/25, 30/30, 30/35, 20/25, 25/25, and 35/25°C (day temperature/night temperature). Prior to and following the application of the temperature treatments the plants were grown under a regime of 30125°C.

Relative growth rates and net assimilation rates (leaf dry weight basis) were both affected during the temperature treatment, with a maximum rate for both at 25/25°C. Flowering was also markedly affected, low temperature favouring flower formation. There was no evidence of a thermoperiodic effect on flower production. Temperature and the period of exposure to that temperature appeared to be the chief determinants of flower production.

Following the temperature treatments, when all plants were being grown under the same regime, there were marked residual effects on both flowering pattern and vegetative growth. The residual effects on flowering could not be related to the number or weight of developing fruits, and it was concluded that the developing fruits did not suppress flowering.

The temperature treatments also led to large differences in the final nut-in-shell and kernel yields. These differences were largely associated with the number of developing pegs, which in turn were correlated with the flower production up to the end of the temperature treatments. It is suggested that the effects of temperature on final yield were the result of temperature on growth leading to differences in flower formation.