2020
Improving Drought Adaptation by Insertion of Limited Transpiration Trait into Soybean Varieties in the Upper Mid-South of the US
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Contributor/Checkoff:
United Soybean Board
Category:
Sustainable Production
Keywords:
(none assigned)
Parent Project:
Improving Drought Adaptation by Insertion of Limited Transpiration Trait Into Soybean Varieties in the Upper Mid-South of the US (1820-172-0118-B)
Lead Principal Investigator:
Avat Shekoofa, University of Tennessee-Institute of Agriculture
Co-Principal Investigators:
Project Code:
2020-172-0159
Contributing Organization (Checkoff):
United Soybean Board
$50,526
Institution Funded:
University of Tennessee-Institute of Agriculture
$50,526
Brief Project Summary:

Unique Keywords:
#environmental stress
Information And Results
Project Deliverables

Final Project Results

Updated February 1, 2021:
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 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 (gs) (Fig. 3). The soybean lines that showed higher water use efficiency (WUEk) also had lower stomatal conductance. The seeds of ten selected breeding lines for TRlim/Drought tolerant trait will be harvested in 2020 for testing in 2021 for their chemical & physical properties.

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