What reproductive stages describe seed fill in soybeans?

Seed fill in soybeans is characterized by the reproductive stages known as R5 and R6. During the R5 stage, the soybean pods reach their full size and the seeds inside begin to develop. This is crucial for the accumulation of dry matter in the seeds, as they start filling with nutrients and carbohydrates. Subsequently, in the R6 stage, the moisture content of the seeds is at its highest, and they continue to fill out, increasing in size and weight as they mature.

These stages are vital in plant development as they significantly influence the final yield. The R5 stage signals the beginning of seed fill, while R6 is where seed fill reaches its peak just before maturity, making them the definitive stages for this crucial development period in soybeans.