Blum, A., Institute of Field and Garden Crops, The Volcani Center, POB 6, Bet Dagan, Israel
Shpiler, L., Institute of Field and Garden Crops, The Volcani Center, POB 6, Bet Dagan, Israel
Golan, G., Institute of Field and Garden Crops, The Volcani Center, POB 6, Bet Dagan, Israel
Mayer, J., Institute of Field and Garden Crops, The Volcani Center, POB 6, Bet Dagan, Israel

The utility of using canopy-temperature sensing under drought-stress as a selection index for drought resistance was evaluated by seeking an association across genotypes between canopy temperatures and yield stability under changing moisture conditions. Sixty-eight and 17 genotypes of wheat (Triticum aestivum and T. durum) were tested in 1986/87 and 1987/88, respectively. All materials were grown under a rainout shelter, either with full irrigation, or under moisture stress which increased as the season progressed. Stability in grain-yield was estimated for each genotype by the 'drought-susceptibility index' derived from the yield difference between stress and non-stress environments. It was compared with midday canopy temperatures under drought-stress, which expressed the relative plant water stress for each genotype. A positive correlation was found in both years (r = 0.64 and r = 0.72, P ≤ 0.01) across genotypes between 'drought-susceptibility index' and canopy temperatures, indicating that 'drought-susceptible' genotypes which suffered relatively greater yield loss under stress also tended to be under greater water-stress and had warmer canopies at midday. These results lend support to the use of two different and well-defined water regimes for the evaluation of yield stability (or 'drought-susceptibility index') under drought-stress, as well as the continued use of canopy temperatures as a tool in selection for drought resistance. © 1989.