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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR AND GENETIC ENHANCEMENT OF ABIOTIC STRESS TOLERANCE IN SORGHUM Title: Selection System for the "Stay-green" Drought Tolerance Trait in Sorghum Germplasm

Authors
item Burke, John
item Franks, Cleve - ADVANTA U.S. INC.
item Burow, Gloria
item Xin, Zhanguo

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2009
Publication Date: May 6, 2010
Citation: Burke, J.J., Franks, C.D., Burow, G.B., Xin, Z. 2010. Selection system for the "Stay-green" drought tolerance trait in sorghum germplasm. Agronomy Journal. 102(4):1118-1122.

Interpretive Summary: Post-flowering drought tolerance is an essential trait for increasing cereal production in Mediterranean climates. Current methodologies for identifying the nonsenescent (stay-green) trait require the right intensity of drought stress at the right developmental stage to visually evaluate lines in the field. Field-based evaluations of drought tolerance are notoriously difficult to manage, and often require growing lines in multiple locations across several years in order to acquire a meaningful assessment of the stay-green trait. We have developed a rapid detection system for identifying sorghum lines exhibiting the stay-green trait. This technique if performed on well watered plants, thereby eliminating a major environmental limitation to the stay-green trait detection. This technology will greatly reduce the selection time needed to identify drought tolerant sorghum.

Technical Abstract: Post-flowering drought tolerance is an essential trait for increasing cereal production in Mediterranean climates. Current methodologies for identifying the nonsenescent (stay-green) trait require the right intensity of drought stress at the right developmental stage to visually evaluate lines in the field. Field-based evaluations of drought tolerance are notoriously difficult to manage, and often require growing lines in multiple locations across several years in order to acquire a meaningful assessment of the stay-green trait. By means of a 30-minute high temperature challenge to leaf tissue from pre-flowering well-waterd sorghum and 30-minute room temperature recovery, we show that stay-green lines can be readily identified. Using chlorophyll fluorescence to monitor tissue injury, we found that tissue with higher intercellular sucrose concentrations exhibited higher chlorophyll fluorescence yield following the temperature challenge. Stay-green lines evaluated in this study maintained higher dawn leaf sucrose levels than the senescent lines among the five youngest leaf positions. Evaluation of ten known stay-green and senescent sorghum lines with this bioassay allowed us to separate the two classes of sorghum from well-watered pre-flowering plants. This technology will greatly reduce the selection time needed to identify drought tolerant sorghum.

Last Modified: 10/22/2014
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