Stomata regulate photosynthesis and transpiration, and these processes are critical for plant responses to abiotic stresses such as salinity. A barley double haploid population with 108 lines derived from a cross between CM72 (salt-tolerant) and Gairdner (salt-sensitive) was used to detect quantitative trait loci (QTLs) associated with stomatal and photosynthetic traits related to salinity tolerance. A total of 11 significant QTLs (LOD > 3.0) and 11 tentative QTLs (2.5 < LOD < 3.0) were identified. These QTLs are distributed on all the seven chromosomes, except 5H and explain 9.5–17.3% of the phenotypic variation. QTLs for biomass, intercellular CO2 concentration, transpiration rate and stomatal conductance under control conditions co-localised together. A QTL for biomass also co-located with one for transpiration rate under salinity stress. A linkage was found between stomatal pore area and gas exchange. A QTL for salinity tolerance also co-localised with QTLs for grain yield and biomass on chromosome 3H. Based on the draft barley genome, the candidate genes for salinity tolerance at this locus are proposed. The lack of major QTLs for gas exchange and stomatal traits under control and saline conditions indicates a complex relationship between salinity and leaf gas exchange due to the fact that these complex quantitative traits are under the control of multiple genes.

Eggplant (Solanum melongena L.) has become an increasingly common vegetable grown in glasshouses. This study emphasized on the physiological traits and productivity of three eggplant cultivars (Longa, Lydia, and Tracey) in a high-tech glasshouse to determine the genotypic differences of agronomical, morphological, and physiological responses. The physiological parameters as well as the productivity of these eggplant cultivars were evaluated. The results showed that Tracey had significantly higher leaf growth than Longa and Lydia. Longa exhibited significantly higher values of net CO₂ assimilation (A), stomatal conductance (g_s), and transpiration rate (T_r) than Tracey, whereas Tracey showed significantly larger g_s, T_r, and intracellular CO₂ concentration (C_i) than Lydia. Tracey showed a significantly higher number of flowers per node compared to the two other varieties, but the number of fruits did not statistically differ among cultivars. Tracy produced the highest yield (fruit weight and fruit yield per m²) due to the significantly higher leaf length and leaf expansion rate despite the lowest level of A among the three cultivars. Interestingly, the higher yield of Tracey translated into better water use efficiency (WUE) in the agronomic term, but its intrinsic WUE (A/g_s) was the lowest among the three cultivars. However, significant correlations between photosynthetic parameters and WUE were only found in certain stages of eggplant growth. Therefore, further research work with an emphasis on the source and sink partitioning of a large number of eggplant genotypes is required to investigate the varietal performance of greenhouse eggplants. Then, the information can be translated into protected cropping to set up the growth benchmark for large-scale sustainable production of eggplants with better yield and less water consumption for the horticultural industry.