Impact of Delaying Irrigation on Wilting, Seed Yield, and Other Agronomic Traits of Determinate MG5 Soybean

Soybean production in the U.S. Mid-South relies heavily on irrigation with 85% of soybean surfaces irrigated in Arkansas. Reduction in irrigation due to water quantity restrictions will significantly affect soybean seed yield, making variety selection increasingly important. The objective of the study was to assess if irrigation onsets at different reproductive stages affect wilting, seed yield, and key agronomic traits on determinate maturity group 5 (MG 5) soybean. One-hundred sixty-five F-4-derived populations of recombinant inbred lines with determinate growth habit, similar maturity, and contrasting wilting potential were planted in an augmented strip-plot design in four environments as a single replicate. Four irrigation onsets were applied at R1 (initiation flower), R2 (full bloom), R3 (initiation pod), and R4 (full pod) using an atmometer. Results indicated significant differences in wilting and yield but no significant differences in maturity, protein, oil concentration, and 100-seed weight across different irrigation onsets. There was no significant difference between the fast and slow wilting genotypes across different irrigation onsets for each trait. Allowable depletions measured in this study indicated that both fast and slow wilting soybean genotype determinate MG5 can tolerate high allowable depletion with no significant yield penalty at R3 growth stage in silt loam soil.