Growth Stages of Peanut (Arachis hypogaea L.)1

Abstract Uniform growth stage descriptions were developed for peanut based on visually observable vegetative (V) and reproductive (R) events. The V stage was determined by counting the number of developed nodes on the main stem, beginning with the cotyledonary node as zero. The last node counted must have its tetrafoliolate leaf sufficiently expanded so the leaflets are unfolded and flat in appearance. The R stages proposed are R1 (beginning bloom), R2 (beginning peg), R3 (beginning pod), R4 (full pod), R5 (beginning seed), R6 (full seed), R7 (beginning maturity), R8 (harvest maturity), and R9 (over mature pod). The V and R stages can be measured separately and concurrently and apply to populations or single plants. For populations, a given stage is reached when 50% of the plants sampled have achieved the specified node number or have one or more flowers, pegs, pods, or seeds exhibiting the specified trait. The stages apply to both Spanish and Virginia type cultivars. The proposed standard descriptions of peanut plant development should aid in peanut research planning and communication and should assist extension recommendation of timing of cultural practices.