Physiological and molecular characterisation of 'stay green' mutants in durum wheat.
About 20.000 seeds of Triticum durum desf. (cv Trinakria) were treated either with EMS (10.000) or with Sodium Azide (10.000) and four M5 progeny plants grown in the field (Foggia, Italy) were chosen for their similar timing of flowering, but later
timing of senescence. Physiological characterisation was carried out in a controlled-environment glasshouse in IACR-Rothamsted, Harpenden, UK. Net photosynthesis, chlorophyll
concentration, leaf internal CO2 (Ci), stomatal conductance and the fluorescence of chlorophyll "a" were measured on attached flag leaves at weekly intervals from flowering until full senescence. Total nitrogen, the nitrogen distribution in protein fractions and HPLC analyses of proteins were also performed on flour milled from randomly selected grains.
Differential display reverse transcription-polymerase chain reaction (DDRT-PCR) was used as molecular technique to identify genes that were differentially expressed in the mutant and control plants. Different stages of leaf development and
combinations of probes were used and the fragments identified were screened for differential expression. The results presented show that an extension of photosynthesis could have
importancef or increasingy ield in durum wheat