1a.Objectives (from AD-416):
To develop high yielding drought tolerant cultivars adapted to North Carolina and other drought-prone U.S. environments.
1b.Approach (from AD-416):
Soybean germplasm will be screened to identify drought tolerance. Putative tolerant types will be verified. Genetics of the tolerance will be investigated. Drought tolerance genes, as found, will be transferred to adapted cultivars. This work will be pursued in lab, greenhouse, and field studies.
This project is related to Objective 3 of this in-house project: to discover novel genes/alleles in soybean for ‘tolerance to drought and related stress’, determine their inheritance, determine genomic location, transfer to adapted germplasm, and release. The Drought Tolerance project seeks to unlock the rich store of drought tolerance genes that exist in the USDA’s preserve of soybean germplasm. This reservoir of exotic diversity, although collected by scientists, was produced originally by over 3000 years of ‘on-farm breeding’ in Asia, in which farmers selected and adapted the soybean for human use under a range of climate conditions. Special genes for drought tolerance, bred into soybean so long ago by these ancient farmers, are key to coping with the problem of drought in the USA today. U.S. varieties do not presently contain these special drought genes from Asia. The central theme of our drought tolerance work is that we can ‘turn the tables’ on drought in the USA by putting the world’s genetic resources in soybean to work on U.S. farms. To that end, the United Soybean Board's drought tolerance project coordinates the research activities of 8 scientists and 7 research institutions in the Midwest and South, aimed at transferring drought genes from exotic Asian material into adapted genetic materials. A major factor determining success in the genetic improvement of drought tolerance is the physiological processes that give rise to drought tolerance. A key physiological process is the genetic response of soybean leaves to drying air and soil conditions. Exotic soybeans have been identified that are ‘slower to wilt’ under drought stress than normal soybean varieties. Breeding efforts of the USDA-ARS Soybean and Nitrogen Fixation Unit have produced advanced drought-tolerant breeding lines based in field evaluation and selection. This project evaluated ten of these new breeding materials for response to specific stress factors. Four had a favorable reaction to drying air and six had superior N fixation under water stress. All had a similar ability to extract water from a drying soil.