Environment, Maturation, and Storage Effects on Rfo, Protein and Oil Composition in Soybeans.

This study investigates soybean seed composition after physiological pre-harvest treatments.  Soybeans were planted at two locations and two years in a randomized-block design with three replications.  Because studies were planted in unique field locations, each planting is counted as a separate environment.  A diverse selection of varieties was planted including two modern and one heirloom, and two fast neutron mutant.  NIR analyses for seed composition was completed on a Perten series instrument.  Pre-harvest treatments include one-meter open environment (R5), moderate depodding (R5), severe depodding (R5), 80% shade (R5), 66% defoliation (R5), 66% defoliation (R6).  These treatments are designed to limit the amount of source photosynthate capacity or limit the amount of sink assimilatory capacity.  Compared against the control averages, 80% shade and defoliation at R6 showed high protein/ low oil and low oil/ high protein, respectively.  This can be attributed to the removal of N stores in the leaves of defoliation treatments which are important for N remobilization into seed protein during seed fill.  A strong negative correlation was observed between protein and oil for all treatments.