Abstract
A consistent risk for soybean (Glycine max L.) production is the impact of drought on growth and yield. Canopy temperature (CT) is an indirect measure of transpiration rate and stomatal conductance and may be valuable in distinguishing differences among genotypes in response to drought. The objective of this study was to map quantitative trait loci (QTLs) associated with CT using thermal infrared imaging in a population of recombinant inbred lines developed from a cross between KS4895 and Jackson. Heritability of CT was 35% when estimated across environments. QTL analysis identified 11 loci for CT distributed on eight chromosomes that individually explained between 4.6 and 12.3% of the phenotypic variation. The locus on Gm11 was identified in two individual environments and across environments and explained the highest proportion of phenotypic variation (9.3% to 11.5%) in CT. Several of these CT loci coincided with the genomic regions from previous studies associated with canopy wilting, canopy temperature, water use efficiency, and other morpho-physiological traits related with drought tolerance. Candidate genes with biological function related to transpiration, root development, and signal transduction underlie these putative CT loci. These genomic regions may be important resources in soybean breeding programs to improve tolerance to drought.
Highlights
A consistent risk for soybean (Glycine max L.) production is the impact of drought on growth and yield
Under optimum moisture conditions, increased vapor pressure deficit increases evaporative demand resulting in higher transpiration rate and a decrease in canopy temperature provided that stomatal conductance does not change
We identified genomic regions associated with Canopy temperature (CT) in a recombinant inbred population derived from KS4895 and Jackson that was phenotyped in six different environments
Summary
A consistent risk for soybean (Glycine max L.) production is the impact of drought on growth and yield. The locus on Gm11 was identified in two individual environments and across environments and explained the highest proportion of phenotypic variation (9.3% to 11.5%) in CT Several of these CT loci coincided with the genomic regions from previous studies associated with canopy wilting, canopy temperature, water use efficiency, and other morpho-physiological traits related with drought tolerance. Candidate genes with biological function related to transpiration, root development, and signal transduction underlie these putative CT loci These genomic regions may be important resources in soybean breeding programs to improve tolerance to drought. Decreased transpiration rate and stomatal conductance under water deficit conditions limits evaporative cooling and leads to increased canopy temperature[18,19,20]. Soil moist. deficit (mm) soybean genotypes under drought had a cooler canopy than fast wilting genotypes and that a cooler canopy was positively associated with grain yield
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