Wheat high temperature tolerance during reproductive growth. I. Evaluation by chlorophyll fluorescence.

(...) Our objective was to evaluate chlorophyll fluorescence, which indirectly measures photosynthetic efficiency, as a screening criterion for high temperature tolerance in wheat. Six genotypes differing in adaptation to the southern Great Plains were tested in two controlled environments and in the field. Plants in controlled environments were subjected to 37/25 °C and 25/20 °C day/night regimes during grain filling and at different developmental stages from late boot to 10 d after anthesis. The field experiment was planted during late winter to increase the probability of high temperature stress after antheis (...)