The Influence of Temperature and Soil Water Deficit on the Development and Morphology of Groundnut (Arachis hypogaeaL.)

The rate/temperature relation of several developmental processes in groundnut was examined in a suite of temperature-controlled glasshouses maintained at mean air temperatures of 19, 22, 25, 28 and 31 °C. The sensitivity of the various processes to soil water deficit was also examined. When the relation between rate and temperature was linear, measurements were analysed in terms of thermal time (°Cd) and an extrapolated base temperature (Tb) at which the rate was zero. Tb was conservative (≏10 °C) for leaf appearance, branching, flowering, pegging and podding. A higher value of Tb for seedling emergence (16 °C) was probably an artifact caused by soil pathogens. Leaf appearance and branching were more sensitive to soil water deficit than the other processes examined.