The effect of mild water deficit starting at the vegetative state on the physiological and biochemical response of wheat was investigated in a pot experiment. Wheat plants were grown in a controlled warming environment, in which the atmospheric CO2 concentration and temperatures were set to match those projected by the end of this century. Three wheat genotypes of different polyploidy level were selected: two bread (hexaploidy) genotypes named Gazul and HTWSN 41 respectively, and a durum (tetraploid) genotype named Regallo. The set of the potted plants of each genotype were split into two groups when they reached stage 14 within the decimal Zadoks growth scale. One was maintained under well water conditions, at field capacity, and another followed mild water deficit imposed at 65% of field capacity. At ear emergence, foliar pigments and leaf photosynthesis were measured. Additionally, flag leaves and ears from a subset of each group per genotype and water treatment were harvested to measure morphophysiological, water-related and biochemical traits. The remaining potted plants were left until maturity. The above- and belowground parts of the plants were harvested and the grains separated from the ears to quantify both yield- and quality-related traits. A total of 81 continuous measures were collected from the analyses performed on flag leaves and ears at ear emergence, and grains and total biomass at maturity. The variables were divided into four blocks named Leaf, Ear, Yield and Quality to performed supervised statistical multivariate analysis with the ade4 package. The statistical analysis of the results showed that three genotypes experienced reductions in leaf nitrogen balance and the number of productive tillers, though leaf photosynthesis and water use efficiency were rather stable. Ear water content and antioxidant status largely remained unchanged. Grain yield per plant decreased in the three genotypes, while grain yield per ear and grain biomass displayed reduced variability. Both leaves and ears equally contribute to grain yield. Under water deficit conditions, bread wheat genotypes showed a significant increase in nitrogen content, whereas Regallo maintained higher stable nitrogen content and better grain quality except for iron content. From a methodological viewpoint, the use of several functions maintaining the structure of an object of the subclass dudi (duality diagram) within the ade4 package open a new predictive statistical methodology in the screening of wheat with relevant organ and grain traits

No description available