CANOPY TEMPERATURES AND EXCISED LEAF WATER LOSS OF TEF (ERAGROSTIS TEF [ZUCC.] TROTTER.) CULTIVARS UNDER WATER DEFICIT CONDITIONS AT ANTHESIS

Abstract

This experiment was carried out to evaluate the canopy temperatures and excised leaf water loss (ELWL) of tef cultivars under water deficit conditions at anthesis and to demonstrate that these indices are reliable indicators of plant water stress. Twelve tef cultivars of similar maturity group but diverse origin were grown in each of two seasons under stressed and non-stressed conditions at anthesis. Mean cultivar canopy temperatures ranged from 33.2 to 34.9°C and 32.2 to 33.8°C in 1998 and 1999, respectively. There was also a significant difference in canopy temperature between treatments. The canopy temperature of stressed plants was 10.7% and 11.4% higher than that of non-stressed plants in 1998 and 1999, respectively. Under stress conditions the canopy temperature of the cultivars ranged from 33.6 to 36.7°C and from 33.1 to 37.6°C in 1998 and 1999, respectively, as compared to the non-stressed plants which ranged from 32.1 to 34.5°C in 1998 and from 29.7 to 31.9°C in 1999. There was a marked difference in mean excised leaf water loss (ELWL) values between the stressed and non-stressed treatments. There was also a differential response among tef cultivars for ELWL in response to the water deficit treatments during 1998 and 1999. Under non-stressed conditions the values of ELWL ranged between 1.5 g/g/h to 2.1 g/g/h in 1998 and 0.8 g/g/h to 1.7 g/g/h in 1999, whereas under stressed conditions the ELWL of the cultivars ranged from 1.0 g/g/h to 1.8 g/g/h and 0.7 g/g/h to 1.3 g/g/h in 1998 and 1999, respectively. The difference between the cultivars for both canopy temperatures and ELWL in response to the water deficit treatment was greater during 1999 than in 1998. It was concluded that both canopy temperatures and ELWL were suitable methods for the screening of drought resistant tef cultivars since differences between cultivars were detected.