160 V. G. Kakani et al.
have not been conducted so far under field conditions. Such studies under con-
trolled environment did not result in any definite conclusions (Craufurd et al. 1999 ).
This study evaluated the effects of high-temperature stress on groundnut yield,
and its interaction with drought, under field conditions. The objectives of this study
are: (1) to investigate the effects of water stress and high temperature on growth,
development and yield of groundnut grown in the semiarid tropics; (2) to test the
possible interaction between water stress and high temperature observed under con-
trolled environment, on yield and yield components under field conditions.
8.2 Materials and Methods
8.2.1 Location, Weather and Soil
An experiment to study the interaction between high temperature and water stress
was conducted at two sowing dates, at the International Crops Research Institute
for Semiarid Tropics (ICRISAT), Patancheru, Hyderabad, India. The ICRISAT is
located in semiarid tropics at an altitude of 545 m above sea level (ASL), 17°32’ N
latitude, 78°16’ E longitude.
A mini weather station (Fig. 8.2a) was set up to record daily values of temperature
and incident solar radiation. Air and soil temperatures were measured using copper–
constantan thermocouples. Air temperatures were measured at canopy level and soil
temperatures at a 10-cm depth (i.e. in the podding zone; Fig. 8.2b). Solar radiation
Fig. 8.1 Diurnal temperature cycle under natural (−) hot environment at ICRISAT, India, and
controlled (−) high temperature treatment (40/22 °C—day/night with 12 h photo-thermoperiod)