Stage of Development Descriptions for Soybeans, <i>Glycine Max</i> (L.) Merrill¹

TLDR

We developed stage‑of‑development descriptions intended to apply to all soybean genotypes grown in any environment. The system defines vegetative stages by counting nodes on the main stem and reproductive stages by key phenological events—flowering, pod, seed, and maturation—providing precise, objective, plant‑ or community‑level descriptors. These standardized stages are expected to improve soybean research and will be used by the hail‑insurance industry to determine crop losses.

Abstract

We developed stage of development descriptions which we believe apply to all soybean ( Glycine max (L.) Merr.) genotypes grown in any environment. The descriptions apply to single plants or a community of plants and are precise and objective. Vegetative and reproductive development are described separately. Vegetative stages are determined by counting the number of nodes on the main stem, beginning with the unifoliolate node, that have or have had a completely unrolled leaf. Reproductive stages Rl and R2 are based on flowering, R3 and R4 on pod development, R5 and R6 on seed development, and R7 and R8 on maturation. The stage descriptions should enhance soybean research by standardizing descriptions of soybean plant development. The system also will be used by the soybean hail insurance industry for stage determination in adjustment of losses.