Soybean breeders will apply the information from the proposed project in multiple ways:

• Defining the association of yield components with yield per se, and precise mapping of the underlying QTL, will produce strategies for screening exotic germplasm to identify novel useful genetic variation to enhance yield.

• New genetic variation derived from exotic pedigrees, either present in SoyNAM lines or identified subsequently, will be used in soybean breeding programs. This will be facilitated by identification of QTL, and positive alleles of QTL, for yield components in the SoyNAM mapping populations.

• Enabled by output from the proposed experiment and SoyNAM genotyping, phenotypic or genotypic selection for physiological yield components can be implemented in breeding populations.

• An enhanced understanding of the genetic variance of physiological yield components will be incorporated into soybean breeding programs. Genetic variance is a measure of the extent to which a trait is controlled by genes versus environmental factors, and whether progress can be made from selection.

The proposed project will generate methods that are relevant to soybean breeders, agronomists, and physiologists:

• Techniques will be developed for rapid and accurate in-field determination of canopy closure and relations to light interception and soybean growth.

• Non-destructive means of estimating soybean yield potential over large populations for breeding selection via crop reflectance measurements will be developed. This has the potential to also be used by public and private crop professionals to assist growers.

• Collection of physiological data on this scale has not occurred previously in soybean. The data management and field informatics techniques implemented during this project can be applied to future activities. This has been the experience of MaizeNAM cooperators.