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United States Department of Agriculture

Agricultural Research Service

Title: Genetic diversity in sorghum transpiration efficiency

Authors
item Xin, Zhanguo
item Aiken, Rob - KANSAS STATE UNIVERSITY
item Burke, John

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 27, 2008
Publication Date: March 15, 2009
Citation: Xin, Z., Aiken, R., Burke, J.J. 2009. Genetic diversity in sorghum transpiration efficiency. Field Crops Research. 11(1-2): 74-80.

Interpretive Summary: The decline in fresh water resources and the increasing demanding for more food, fiber, and fuel production pose a great challenge to agriculture. Crops with high transpiration efficiency (TE) as defined by the total biomass produced per unit water transpired are urgently needed to sustain or increase agriculture production while preserving the valuable fresh water resources. As a drought-tolerant and water-use efficient C4 plant, sorghum is commonly grown under rain-fed conditions in the Southern Plains and other semi-arid regions in the world. Thus, its production is strongly affected by the availability of soil water during the growing season. Enhancing TE may be an effective approach to increase sorghum yield in arid and semi-arid regions under no or limited irrigation. In this report, we surveyed 406 sorghum accessions for variation in TE. A selection of 25 lines was confirmed at Lubbock, TX and Colby, KS. Significant variation in TE was identified at both locations. While most lines displayed different ranking in TE at the two locations, several lines with consistent high or low TE were identified. TE based on biomass production was strongly correlated with increased biomass accumulation rather than reduced transpiration. Gas-exchange analysis of eight selected lines indicated that low internal CO2 concentration and enhanced photosynthetic capacity may contribute to the variation in TE. The results suggest that considerable genetic variation in TE exists in sorghum germplasm collection and that TE is strongly influenced by environment.

Technical Abstract: Sorghum is the fifth most important grain crop and is becoming increasingly important as a biofuel feedstock due to its superior tolerance to water deficit stress. Sorghum is commonly grown under rain-fed conditions in the Southern Plains and other semi-arid regions in the world. Thus, its production is strongly affected by the availability of soil water during the growing season. Enhancing transpiration efficiency (TE), defined as biomass accumulation per unit water transpired, may be an effective approach to increase sorghum yield in arid and semi-arid regions under no, or limited, irrigation. In this report, we surveyed 406 sorghum accessions for variation in TE. A selection of 25 lines was confirmed at two locations that have different experimental conditions and water regimes. Significant variation in TE was identified at both locations. While most lines displayed different ranking in TE at the two locations, several lines with consistent high or low TE were identified. TE based on biomass production was strongly correlated with increased biomass accumulation rather than with reduced transpiration. Gas-exchange analysis of eight selected lines indicated that low internal CO2 concentration and enhanced photosynthetic capacity may contribute to the variation in TE. The results suggest that considerable genetic variation in TE exists in sorghum germplasm collection and that TE is strongly influenced by environment.

Last Modified: 12/21/2014
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