Current Projects
Research of Soybean Tolerance to Waterlogging and Drought Funded by the Southern Soybean Research Program and the United Soybean Board
Dr. J. Grover Shannon of the University of Missouri , Delta Center is carrying out joint research projects that explore tolerance of various soybean varieties when exposed to waterlogging, but also drought.
Waterlogging
Plant yellowing, reduction in nitrogen fixation, stunted growth, leaf defoliation and plant death can all be results of soybean flooding. The Southern Soybean Research Program (SSRP) has challenged Dr. Shannon in identifying soybeans that can best tolerate these stressful conditions.
Studies began with flood testing in two stages-complete submergence of the whole plant, and waterlogging defined as a portion of the root and shoot exposed to flooding.
Three objectives are hoped to be derived from this project:
The SSRP voted to fund this research due to the fact that there is little known about flood tolerance for most of today’s varieties as only 500 of 17,000 PIs are screened for flood tolerance. It is very likely to have lines with higher tolerance. The study spans over two years beginning in 2008 and to be continued this growing season.
In 2008, Shannon conducted screening on a zero grade heavy clay field. There he screened four Group III varieties of which two showed some tolerance; 122 varieties of Group IV where eight showed some tolerance; and he screened 72 varieties of Group V with 20 varieties showing some tolerance.
Dr. J. Grover Shannon of the University of Missouri , Delta Center is carrying out joint research projects that explore tolerance of various soybean varieties when exposed to waterlogging, but also drought.
Waterlogging
Plant yellowing, reduction in nitrogen fixation, stunted growth, leaf defoliation and plant death can all be results of soybean flooding. The Southern Soybean Research Program (SSRP) has challenged Dr. Shannon in identifying soybeans that can best tolerate these stressful conditions.
Studies began with flood testing in two stages-complete submergence of the whole plant, and waterlogging defined as a portion of the root and shoot exposed to flooding.
Three objectives are hoped to be derived from this project:
1. To determine tolerance to field waterlogging and drought among group III, IV and V soybean varieties and exotic gerplasm lines (Plant Introductions or PI’s).
2. To identify the levels of tolerance amongst the most tolerant soybean varieties.
3. To provide information to soybean producers so they may make the most economical decisions when selecting varieties based on their tolerance of waterlogging and drought.
2. To identify the levels of tolerance amongst the most tolerant soybean varieties.
3. To provide information to soybean producers so they may make the most economical decisions when selecting varieties based on their tolerance of waterlogging and drought.
The SSRP voted to fund this research due to the fact that there is little known about flood tolerance for most of today’s varieties as only 500 of 17,000 PIs are screened for flood tolerance. It is very likely to have lines with higher tolerance. The study spans over two years beginning in 2008 and to be continued this growing season.
In 2008, Shannon conducted screening on a zero grade heavy clay field. There he screened four Group III varieties of which two showed some tolerance; 122 varieties of Group IV where eight showed some tolerance; and he screened 72 varieties of Group V with 20 varieties showing some tolerance.
| Varieties with best tolerance (1-year data only) | |
| MG II | NK S39-A3 |
| Hornbeck HBK 3927 | |
| MG IV | Trisoy 4586 |
| Southern Cross Caleb | |
| Progeny 4908 | |
| Asgrow 4303 | |
| MG V | USG 75Z-38 |
| Delta Grow 5160 RR STS | |
| Dyna-Gro 32-A52 | |
According to Shannon , soybean varieties have a narrow gene pool so they can be traced back to only a few ancestors. PIs from Asia have the most promise for providing complete flood tolerance.
After screening PIs, several have shown enough promise for further study. In 2009, 23 Group IIIs, 28 Group IVs and 6 Group Vs lines with be selected for further study.
In 2009, Shannon plans to measure level of tolerance of the best lines by identifying lines with the least amount of damage by determining yield loss under drought versus irrigated conditions. Then provide the results to growers and companies for breeding programs to develop flood tolerant varieties.
Drought
The United Soybean Board (USB) is providing Dr. Shannon with checkoff support to conduct the same study but to reverse the waterlogging and screen for drought tolerance. In addition to finding drought tolerance varieties, Shannon will be able to answer the question: Are there varieties and exotic germplasm lines that have both tolerance to flooding and drought?
Drought is the number one factor when it comes to yield loss. In this study drought tolerance was based on wilting scores and pod set at the end of the season. It was found that there was less variation among varieties for wilting (varieties looked similar except at maturity where there was variation for pod set). Promise of tolerance was shown in two of the 4 group IIIs; 29 of the 122 group IVs and 12 of the 72 group Vs.
When examining PIs, more variation was found for wilting and also at maturity for pod set. Promise of tolerance was shown in 30 of the 177 group III-PIs; 82 of the 349 group IV-PIs and 18 of the 176 group V-PIs.
Finally, do some flood tolerant varieties and PIs also show drought tolerance? And the answer is, yes, but year two will confirm findings and allow Shannon to name varieties and PIs resistant to both. 2009 research will look heavily on nine varieties that could be tolerant to both and 22 PIs that show the same promise.
For more information on Dr. Shannon’s research contact him
at 573-379-4036 or shannong@missouri.edu.
After screening PIs, several have shown enough promise for further study. In 2009, 23 Group IIIs, 28 Group IVs and 6 Group Vs lines with be selected for further study.
| PIs Showing Best Tolerance (1-year data only) | |
| PI 567506 (III) | Flood Score 1.5 |
| PI 567519 (III) | Flood Score 1.5 |
| PI 567593A (III) | Flodd Score 1.0 |
| PI 567650A (IV) | Flood Score 2.0 |
| PI 587607A (IV) | Flood Score 1.5 |
| PI 594430A (IV) | Flood Score 1.8 |
| PI 594431 (V) | Flood Score 2.5 |
| Data based on scores from 1-no flood injury to 5-all plants dead. Tests were rated after flooding plots for 10 days to two weeks. Then, plots were flooded a second time for ten days to two weeks and rated again. Ratings are based on plant recovery after the second flood. | |
In 2009, Shannon plans to measure level of tolerance of the best lines by identifying lines with the least amount of damage by determining yield loss under drought versus irrigated conditions. Then provide the results to growers and companies for breeding programs to develop flood tolerant varieties.
Drought
The United Soybean Board (USB) is providing Dr. Shannon with checkoff support to conduct the same study but to reverse the waterlogging and screen for drought tolerance. In addition to finding drought tolerance varieties, Shannon will be able to answer the question: Are there varieties and exotic germplasm lines that have both tolerance to flooding and drought?
Drought is the number one factor when it comes to yield loss. In this study drought tolerance was based on wilting scores and pod set at the end of the season. It was found that there was less variation among varieties for wilting (varieties looked similar except at maturity where there was variation for pod set). Promise of tolerance was shown in two of the 4 group IIIs; 29 of the 122 group IVs and 12 of the 72 group Vs.
When examining PIs, more variation was found for wilting and also at maturity for pod set. Promise of tolerance was shown in 30 of the 177 group III-PIs; 82 of the 349 group IV-PIs and 18 of the 176 group V-PIs.
| PIs Showing Best Tolerance for Drought | |
| PI 567543A (III) | Wilting Score 2.0 |
| PI 567645A (III) | Wilting Score 1.8 |
| PI 538383 (IV) | Wilting Score 1.0 |
| PI 567318 (IV) | Wilting Score 1.5 |
| PI 567333B (V) | Wilting Score 1.5 |
Finally, do some flood tolerant varieties and PIs also show drought tolerance? And the answer is, yes, but year two will confirm findings and allow Shannon to name varieties and PIs resistant to both. 2009 research will look heavily on nine varieties that could be tolerant to both and 22 PIs that show the same promise.
For more information on Dr. Shannon’s research contact him
at 573-379-4036 or shannong@missouri.edu.
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