Location: Plant Science Research
Project Number: 6070-11000-010-018-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2021
End Date: Sep 30, 2022
The objective of this project will be to identify genetic sources of heat stress tolerance in soybean for breeders to use in their programs to improve the abiotic stress tolerance of soybean. Breeding lines known to be drought tolerant will be tested to determine if drought tolerance is associated with heat stress tolerance. If drought and heat stress responses are not linked, then more diverse soybean germplasm will be screened for heat stress response and the results transferred to soybean breeders.
The project will screen soybean germplasm for heat stress tolerance, taking advantage of the unique outdoor facilities designed and constructed by USDA-ARS at Raleigh, NC, for the purpose of studying the heat stress response of crops. Germplasm will be selected in consultation with soybean breeders within USDA-ARS and university colleagues. Initial screening will be conducted in a temperature gradient greenhouse with follow-up trials in elevated temperature field plots. Both systems provide elevated temperature treatments of up to +4 degrees Celsius throughout the growing season to provide an integrated assessment of temperature response across all developmental stages. This elevated temperature regime is in line with predicted future temperature increases of 2-4 degrees Celsius. Well-drained commercial potting mix will be used to minimize disease pressure and allow frequent irrigation so that heat stress can be assessed in the absence of other stress factors during this initial screening process. Lines that perform well in the greenhouse will be validated in field plots where seeds will be sown directly into the ground rather than in pots, and our custom Air Exclusion System (AES) used to provide heat stress treatments. The AES is engineered to provide elevated temperature treatments with a combination of electrical resistant heaters and solar-heated water. Rating for heat stress response will be based on seed yield and harvest index for plants grown to maturity under season-long elevated temperature conditions. We will focus on maturity groups IV through VII with appropriate check cultivars included for comparison.