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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR AND GENETIC ENHANCEMENT OF ABIOTIC STRESS TOLERANCE IN SORGHUM

Location: Plant Stress and Germplasm Development Research

Title: Leaf dhurrin content is a quantitative measure of the level of pre- and post-flowering drought tolerance in sorghum

Authors
item Burke, John
item Chen, Junping
item Burow, Gloria
item Rosenow, Darrell -
item Mechref, Yehia -
item Payton, Paxton
item Xin, Zhanguo

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 18, 2012
Publication Date: March 8, 2013
Citation: Burke, J.J., Chen, J., Burow, G.B., Rosenow, D., Mechref, Y., Payton, P.R., Xin, Z. 2013. Leaf dhurrin content is a quantitative measure of the level of pre- and post-flowering drought tolerance in sorghum. Crop Science. 53(3):1056-1065.

Interpretive Summary: Post-flowering drought tolerance (stay-green) is a key trait for increasing the production of sorghum. Unfortunately, assessment of the stay-green phenotype is dependent on the occurrence of drought stress conditions at specific developmental stages in order to achieve meaningful evaluation. Thus, field-based evaluations, most of which are visual, of stay-green drought tolerance are notoriously difficult to perform and require growing lines in multiple locations across several years to achieve efficient selection for the trait. We have identified a compound (dhurrin) whose accumulation in sorghum leaves correlates to the level of post-flowering drought tolerance and is highly correlated with the stay-green phenotype. Additionally, relationship between leaf dhurrin content and stay-green drought tolerance is stable across irrigation regimes and may be used as a screening tool during pre-flowering sorghum growth, eliminating the need for field-based screening and difficult visual ratings when environmental conditions are variable.

Technical Abstract: Post-flowering drought tolerance is a key trait for increasing the production of sorghum [Sorghum bicolor (L.) Moench] in Mediterranean and semiarid tropical climates. The nonsenescent trait, stay-green, is the most significant criterion for assessing post flowering drought tolerance in sorghum. However, assessment of the stay-green phenotype is dependent on the occurrence of drought stress conditions at specific developmental stages in order to achieve meaningful evaluation. Thus, field-based evaluations, most of which are visual, of stay-green drought tolerance are notoriously difficult to perform and require growing lines in multiple locations across several years to achieve efficient selection for the trait. Here we report and demonstrate that leaf dhurrin [(S)-p-hydroxymandelonitrile-ß-D-glucopyranoside] content from irrigated or dryland sorghum is significantly correlated with the level of post-flowering drought tolerance of sorghum lines previously reported as stay-green. The correlation between leaf dhurrin content and post-flowering drought tolerance provides the first quantitative measure of post-flowering stress tolerance from irrigated or dryland pre-flowering sorghum.

Last Modified: 4/19/2014
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