Temperature, Photoperiod, and Light Intensity Effects on Growth of Pisum sativum L.1

Abstract

Controlled environment chambers were used to study the effect of three factors (temperature, photoperiod, and light intensity) on the growth (dry weight) of seven pea (Pisum sativum L.) introductions and three pea cultivars. The design of the experiment was a split plot with three large temperature chambers divided in the center with one photoperiod treatment on each side. Each photoperiod chamber was then divided by a horizontal partition into two light intensity chambers. The three temperatures, low, medium, and high, were 12 C, 17.5 C, and 25 C. The two photoperiods were 12 hours light and 18 hours light. The two light intensities were 21,500 and 43,000 lux.Growth was much greater at the medium temperature than at either the high or low. The relatively unfavorable effect of low temperature was partly offset by the most favorable light regime, namely long day combined with high light intensity. Of the four light regimes, the results from two were similar and from two others were very dissimilar. The best growth was with long day and high light intensity. The poorest growth was with short day and low light intensity. The two recombinations (short day plus high intensity and long day plus low intensity) were not different in growth response. The first order interactions involving temperature were all significant indicating that temperature response was modified by both day length and light intensity effects.