Main project – summary and project purposes: 1999-2016, in the United States 2427 drought events/year are recorded causing an average loss of 1684 million US dollars per year. Importantly, 2018 drought report shows there is no evident changing tendency in annual economic damages of floods and droughts, despite an upward trend in their annual occurrences. The U.S. 2018 Drought Monitoring data shows statistically significant effect of drought on soybean yields equal to reduction of 1.2% for each additional week of drought in dryland counties and to %0.5 in irrigated counties. A solution to this challenge in corn and peanut has been the exploitation of two specific physiological traits that conserve soil water to support seed development, later.

The ultimate purpose of this research is the development of Tennessee soybean varieties that will confer drought tolerance. The first year of this research has identified candidate lines (commercial and breeding) that express on e or both of two specific physiological traits that result in water conservation, drought tolerance, and recovery, The first 2 years of this study was done in controlled and filed environments. The purpose of the third-year of study is to confirm the extent of drought tolerance (both in field and controlled conditions) and recovery (in controlled environment) expressed by these soybean varieties under rainout shelter condition and comparison of transpiration (TR) recovery from deficit stress a few days after plots will be irrigated. At harvest the seeds protein and oil quality will be measured per genotype per treatment. The lines confirmed to have enhanced drought recovery will be used in breeding for drought-tolerant lines.
Sub-project – goal: Severe flooding has many low-lying soybean fields underwater in mid-south of the U.S., Tennessee included. Results show that an average of 6520 floods has occurred per year during 1996-2016, with annual mean economic losses up to 3986 million US dollars. The purpose of this project is to identify TN soybean genotypes that sustain growth and development under flooding (water stress) conditions.

Main project: Tennessee soybean varieties that exhibit specific water conservation traits that are found to result in delayed wilting and drought tolerance under field and controlled will be identified. The drought stress recovery scoring in controlled environment will be compared with the best recovery rating level among varieties to be able to identify those genotypes with fastest recovery rate. The advanced breeding population that perform one or both water conservation traits will be advanced specifically for drought-prone conditions. The commercial genotypes with high recovery score will be informed.

Sub project: Tennessee soybean varieties that can sustain growth and leaf development with low leaf damage scores will be identified. Tested genotypes will be ranked from flood tolerant, moderately flood tolerant, flood sensitive, and high flood sensitive. Then a selection of lines will be set aside for a field test, next year.