Response to Temperature in a Stand of Pearl Millet

Abstract

Stands of pearl millet were grown in glasshouses in which mean air temperature was controlled to 19, 22, 25, 28 and 31 °C with an amplitude of ±5 °C. During the main growth period, leaf area index increased at a constant rate which was proportional to mean temperature above a base of 10 °C. The warmest stand, therefore, intercepted more radiation before anthesis but the transmission coefficient was independent of temperature (K ≏ 0.3). Based on dry weight at final harvest, the efficiency of conversion for intercepted radiation ranged from about 2.1–2.4 g MJ⁻¹ consistent with field experience. Combining this information with figures for the duration of growth in relation to temperature suggests that growth rate should be maximal at 25–27 °C and total dry weight at 20–22 °C.