ARS | Publication request: Genetic diversity in sorghum transpiration efficiency

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
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[abstract]. American Society of Plant Biologists, June 26-July 1, 2008, Merida, Mexico. CDROM.

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 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. A collection of 406 sorghum accessions were screened for variation in TE. Twenty-five lines were selected to conduct re-confirmation studies 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 rank in TE at the two locations, several lines with consistently greater or less 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 decreased internal CO2 concentration and enhanced PEP carboxylase activity may contribute to the increase in TE. The results indicate that considerable genetic variation in TE exists in sorghum germplasm collection and that TE is strongly influenced by environment.