Updated January 31, 2022:
Currently, the yield data from both locations for 2020 are processed following the statistical methods. The soybeans plots were harvested in mid-November. The seeds quality measurements also are in process in Dr. Shekoofa’s crop physiology lab at the University of Tennessee. When the seeds quality monitoring will be finished then, all seeds from both locations per genotype will be counted and packaged for Spring 2021, planting season. The ten superior soybean lines will be planted under rainfed conditions in the same two locations which they were planted in 2020. Therefore, the experiment will be repeated to compare the impact of environmental changes on soybeans drought tolerant trait, physiological parameters, and yield sustainability under stress in each location in two years.

Part of this research project results was presented by the project’s PI during an invited talk at 2020 Tri-societies (ASA-CSSA-SSSA) Virtual-annual meeting in November 2020.

Furthermore, Dr. Shekoofa is working toward hiring a postdoc research fellow to assist with the current project’s data analysis, and publications.

Updated January 31, 2022:
Harvested seeds from both locations in 2020 for each soybean lines are in process of counting, packaging, and labeling for Spring 2021, planting season. In 2021, all ten superior soybean lines will be planted in the same two locations which were planted in 2020. The experiment will be repeated to compare the impact of environmental changes on soybeans drought tolerant trait, physiological parameters, and yield sustainability under dryland in each location for both years.

The field trials’ map and plan are in process. The experimental plots will be under rainfed conditions at West TN Research & Education Center (WTREC) in Jackson as well as Milan Research & Education Center (MREC). Areas for 2021 research plots in both locations have been selected and soon the work plans will be submitted to each station director.

A new postdoc was hired, and he will be joining Dr. Shekoofa’ s research lab during the last week of March 2021 to assist with the current research project’s data analysis, and publications.

Updated January 31, 2022:
In two locations in West Tennessee including Jackson WTREC and Milan REC, soybean RILs from crossing ‘KS4895’ x ‘Jackson’ [parental lines] were planted in three replications in mid-May 2021. A fungicide was applied at planting. And an insecticide was applied earlier in June to manage pests. The crop is currently looking good in each location. All our plots are under rainfed/dryland conditions.
We are monitoring soybean plants growth and development regularly in Milan REC and Jackson WTREC. Plots in both locations are being scouted weekly for insects and diseases that might require treatment. The sampling and data collection will be started around early to mid-July for both locations, when the crop water deficit stress is developed.

Dr. Sarkar (a postdoc researcher) joined the current project team on March 29th, 2021. Currently, he is drafting a paper based on the project previous years’ data. Also, he will be working with my research associate and lab assistant to collect data from both field’s locations during summer 2021.

Updated January 31, 2022:

View uploaded report

Updated January 31, 2022:
Drought conditions in the United States are estimated to result in average annual losses in the range of $10 to $14 billion. Identification of genetic mechanisms for tolerating periods of drought is critical to sustaining crop production and yield. Therefore, over 1000 de-rooted shoots of 150 upper mid-south soybean lines were tested using silver nitrate to determine the expression of the limited transpiration (TRlim) trait (i.e., slow wilting) among soybean lines under high evaporative demand (> 2.5 kPa). Among 122 lines, half of the population showed higher sensitivity (fast wilting) to silver nitrate than their parents. However, several lines showed no or limited changes in water loss (slow wilting) with the silver treatment. Therefore, after the silver treatment 26 lines out of 122 were selected for measuring the whole plant transpiration rate under dry air (i.e., high evaporative demand) in a walk-in growth chamber. All 26 lines were divided into 3 categories: 1) slow, 2) moderate, and 3) fast wilting based on silver test results. The whole plant transpiration results indicated that 71% of category 1, 40% of category 2, and 33% of category 3 soybean lines expressed limited water loss which shows water saving potential under dry air in a controlled environment. The lowest transpiration rate (and presumably most water saving) lines had a combination of Quantitative Trait Locus (QTL) from two different parents (Chr10, Jackson; Chr12, KS2495). Lines which inherited alleles from KS4895 for the Chr12 QTL for Canopy temperature (which was genetically distinct from the TR QTL) had lower canopy temperatures (0.84 °C on average across all RILs). Moreover, the soybean lines that showed limited water loss during whole plant transpiration test in contolled environemnts were studied under field conditions in 2020. A correlation was found between water use efficiency intrinsic (WUEk) and lower stomatal conductance. Soybean lines that showed higher water use efficiency (WUEk) also had lower stomatal conductance. In average genotypes with expressing the TRlim/Drought tolerant trait (i.e., RILs #91, #22, #151, and #93) had 20-22% higher yield than other soybean genotypes (2020-2021).