Submitted to: Book Chapter
Publication Type: Proceedings
Publication Acceptance Date: 1/20/2004
Publication Date: 3/20/2004
Citation: Orf, J.H., Hutton, S.F., Carter Jr, T.E. Breeding for soybean drought tolerance: update on u.s. experience. Proc. World Soybean Conf. VII, Fox do Iguassu, PR, Brazil, February 29-March 5, 2004. Embrapa Soybean, Londrina, P.R. Brazil. pp. 1344. Interpretive Summary: In the USA, weeds, diseases and pests are often reasonably well-controlled. However, fluctuations in soybean yield continue to be great from year to year. These yearly differences in yield on the same farm are often due to drought stress. There is more optimism now than ever before that these problems can be solved through breeding. Multidisciplinary teams consisting of plant breeders, physiologists, and molecular geneticists are working together to coordinate research to reduce the impact of drought stress on soybean yield. Current focus is on transferring drought tolerance genes discovered in southern USA germplasm to Midwestern breeding. The practical outcome of this research will be varieties which are more tolerant of stress and better able to produce soybeans at a profit. Our purpose in this presentation was to provide a brief update on breeding for drought tolerance in the USA.
Technical Abstract: This paper reviews progress in breeding soybean cultivars resistant to drought.. Approaches to breeding for drought tolerance in soybeans have involved several mechanisms, including drought avoidance, slow canopy wilting, prolific rooting, and selecting for higher yield under drought conditions. These approaches are outlined in this paper. Most of the progress in breeding for drought tolerance to date has occurred in the Southern USA. This report highlights recent advances in the Midwest. These advances consist of 1) development of Midwestern breeding lines that carry drought tolerance genes derived from southern germplasm, and 2) discovery of exotic Midwestern-maturity plant introductions (PIs) from Asia which are slow wilting. In 2003, a severe drought developed in much of the Midwest, allowing these new genetic materials to be tested under good screening conditions. Many breeding lines and PIs were identified which wilted more slowly than current Midwestern cultivars. The new genotypes are serving as the basis for an expanded drought tolerance breeding program in the Midwest.