Chlorophyll content, chlorophyll fluorescence and water deficit in spring wheat

Using greenhouse techniques that nearly-simulate field water deficit would be a supplemental method for screening potential cultivars adapted to water deficit environments. The objective of this study was to determine if there were differential responses to water deficit in chlorophyll content and chlorophyll fluorescence, and determine the drought susceptibility index (DSI) amongst eight genetically diverse wheat cultivars. An experiment was conducted in three replicates where chlorophyll content and chlorophyll fluorescence were measured at 30 days after planting following (a) an early seedling stage water deficit treatment, and (b) a non-water-deficit treatment. A separate experiment was conducted, using a common protocol, to determine the DSI. Water deficit decreased chlorophyll a, b, and total chlorophyll content in all cultivars and caused a decrease in photosynthetic efficiency (PSE) by between 44.5 and 55.7%. Results showed significant (P < 0.05) cultivar x water treatment interaction for chlorophyll a, total chlorophyll and PSE and cultivars differed significantly for DSI.