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Leaf gas exchange and water-use efficiency of dry-land wheat genotypes under water stressed and non-stressed conditions Section B Soil and plant science

Tshikunde, Nkhathutsheleni Maureen, Odindo, Alfred, Shimelis, Hussein, Mashilo, Jacob
Acta agriculturæ Scandinavica 2018 v.68 no.8 pp. 738-748
arid lands, breeding, carbon dioxide, drought tolerance, gas exchange, genetic variation, genotype, leaves, photosynthesis, physiological response, principal component analysis, water stress, water use efficiency, wheat
The objective of this study was to determine drought tolerance characteristics of dryland wheat genotypes based on leaf gas exchange and water-use efficiency in order to identify promising genotypes for drought tolerance breeding. Physiological responses of ten genetically diverse wheat genotypes were studied under non-stressed (NS) and water stressed (WS) conditions using a 2 × 10 factorial experiment replicated 3 times. A highly significant water condition × genotype interaction (P < 0.001) was observed for photosynthetic rate (A), ratio of photosynthetic rate and internal CO₂ concentration (A/Cᵢ), ratio of internal and atmospheric CO₂ (Cᵢ/Cₐ), intrinsic (WUEᵢ) and instantaneous (WUEᵢₙₛₜ) water-use efficiencies suggesting genotypic variability among wheat genotypes under both test conditions. Principal component analysis (PCA) identified three principal components (PC’s) under both test conditions accounting for 84% and 89% of total variation, respectively. Bi-plot analysis identified G339 and G344 as drought tolerant genotypes with higher values of A, T, gs, A/Cᵢ, WUEᵢ and WUEᵢₙₛₜ under WS condition. The current study detected significant genetic variation for drought tolerance among the tested wheat genotypes using physiological parameters. Genotypes G339 and G344 were identified to be drought tolerant with efficient A, T, gs, A/Ci and water-use under water stressed condition.