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ARS Home » Southeast Area » Raleigh, North Carolina » Soybean and Nitrogen Fixation Research » Research » Publications at this Location » Publication #299392
Title: Evaluation of elite southern maturity soybean breeding lines for drought tolerant traits

Author
item DEVI, JYOSTNA - North Carolina State University
item SINCLAIR, THOMAS - North Carolina State University
item CHEN, PENGYIN - University Of Arkansas
item Carter Jr, Thomas

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2014
Publication Date: 10/29/2014
Citation: Devi, J., Sinclair, T., Chen, P., Carter Jr, T.E. 2014. Evaluation of elite southern maturity soybean breeding lines for drought tolerant traits. Agronomy Journal. 106(6):1947-1954.

Interpretive Summary: Drought is a major reason for crop loss. Breeding efforts in soybean have addressed this problem through the selection of elite genetic lines which have improved yielding ability during water stress. However, the physiological and genetic basis for the improved yields of these genotypes is largely unknown. This study investigated 10 advanced soybean breeding lines which were selected for improved drought tolerance in the field. Three mechanisms of drought tolerance were evaluated. Most of these lines were expressed and unusual water-conserving stomatal response and improved nitrogen fixation during stress. The fact that these rare traits were observed in these advanced lines, even though they were selected only for agronomic performance in the field, demonstrates that these traits are important to applied breeding efforts aimed at improving drought tolerance.

Technical Abstract: Drought is a major reason for crop loss. Breeding efforts in soybean have addressed this problem through the selection of elite genetic lines which have improved yielding ability during water stress. However, the physiological and genetic basis for the improved yields of these genotypes is largely unknown. The objective of this study was to determine the expression of three putative drought-tolerant traits in ten elite southern breeding lines that might account for their yield increase: (1) limited transpiration rate under high vapor pressure deficit (VPD), (2) early decrease in transpiration rate with soil drying, and (3) drought tolerant nitrogen fixation. Unlike most soybean cultivars, nine of the ten elite lines expressed a limited transpiration rate under elevated VPD, which allows soil water conservation during the growing season. Nitrogen fixation drought tolerance of all ten lines was superior to what is commonly observed in soybean. This study demonstrated that empirical selection for high yield and agronomic desirability under water-limited conditions has generally resulted in the selection of physiological traits contributing to drought tolerance.