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Genotypic variation in whole-plant transpiration efficiency in sorghum only partly aligns with variation in stomatal conductance

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Geetika, G., van Oosterom, E. J., George-Jaeggli, B., Mortlock, M. Y., Deifel, K. S., McLean, G. and Hammer, G. L. (2019) Genotypic variation in whole-plant transpiration efficiency in sorghum only partly aligns with variation in stomatal conductance. Functional Plant Biology, 46 (12). pp. 1072-1089.

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Article Link: https://doi.org/10.1071/FP18177

Publisher URL: https://www.publish.csiro.au/paper/FP18177


Water scarcity can limit sorghum (Sorghum bicolor (L.) Moench) production in dryland agriculture, but increased whole-plant transpiration efficiency (TEwp, biomass production per unit of water transpired) can enhance grain yield in such conditions. The objectives of this study were to quantify variation in TEwp for 27 sorghum genotypes and explore the linkages of this variation to responses of the underpinning leaf-level processes to environmental conditions. Individual plants were grown in large lysimeters in two well-watered experiments. Whole-plant transpiration per unit of green leaf area (TGLA) was monitored continuously and stomatal conductance and maximum photosynthetic capacity were measured during sunny conditions on recently expanded leaves. Leaf chlorophyll measurements of the upper five leaves of the main shoot were conducted during early grain filling. TEwp was determined at harvest. The results showed that diurnal patterns in TGLA were determined by vapour pressure deficit (VPD) and by the response of whole-plant conductance to radiation and VPD. Significant genotypic variation in the response of TGLA to VPD occurred and was related to genotypic differences in stomatal conductance. However, variation in TGLA explained only part of the variation in TEwp, with some of the residual variation explained by leaf chlorophyll readings, which were a reflection of photosynthetic capacity. Genotypes with different genetic background often differed in TEwp, TGLA and leaf chlorophyll, indicating potential differences in photosynthetic capacity among these groups. Observed differences in TEwp and its component traits can affect adaptation to drought stress.

Item Type:Article
Business groups:Crop and Food Science
Keywords:photosynthesis, Sorghum bicolor (L.) Moench, vapour pressure deficit.
Subjects:Science > Botany > Genetics
Agriculture > Agriculture (General) > Agricultural meteorology. Crops and climate
Agriculture > Agriculture (General) > Methods and systems of culture. Cropping systems
Plant culture > Field crops > Sorghum
Live Archive:12 Nov 2019 03:44
Last Modified:20 Mar 2024 03:00

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