Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)
Jeudi 28 septembre 2017
Salle A – (Bâtiment 1) à 14h00
Transpiration limitation under elevated vapor pressure deficit for yield increase: From model to phenotype to physiology to cultivar
Thomas R. Sinclair
Université de caroline du Nord (NCSU) Etats Unis
Water deficit is the major constraint on increasing crop yield in many regions of the world. Effective use of available water, therefore, is critical in minimizing the water constraint. Limiting transpiration rate under elevated vapor pressure deficit is a putative plant trait for conserving soil water to sustain crop physiological activity in developing drought. Research on this trait has gone full circle beginning with exploration of the hypothesis using a mechanistic model. Then in soybean, research was done to search for genetic variability in expression of the trait, investigate its physiological basis, breed for improved cultivars, and finally, analyze using a mechanistic model the geospatial viability of the trait. Genotype PI 416937 was identified to express no further increase in transpiration rate at vapor pressure deficit greater 2 kPa. Low hydraulic conductivity in the leaves of this genotype indicated that the leaf capacity for water flux was limiting transpiration rate at high vapor pressure deficit. Low hydraulic conductance was consistent with the insensitivity of PI 416937 to treatment of aquaporin-limiting silver ions. That is, absence of silver-sensitive aquaporins was hypothesized to be the basis of the lower hydraulic conductance of this genotype. Breeding efforts using PI 416937 has now led to released soybean germplasm and varieties. Simulation studies using a mechanistic soybean model has indicated the transpiration-limiting trait would result in yield increases in 85% or more seasons in many locations in US and Africa.
Dr. Sinclair’s research career has involved various aspects of the interaction between physiological processes and the abiotic environment, particularly water deficit. This research has been synthesized in the development of the Simple Simulation Model (SSM). Also, this research contributed to the development of several crop cultivars. Most this research was done during his 30 years at the University of Florida, and has been continued in his current position at North Carolina State University.