Growth stages of corn are divided into vegetative stages (V) and reproductive stages (R) as outlined in Table 1. Subdivisions of the V stages are designated numerically as V1, V2, V3, etc. through V(n), where (n) represents the last leaf stage before VT for the specific hybrid under consideration. The first and last V stages are designated as VE (emergence) and VT (tasseling). The number of leaves (n) will fluctuate with hybrid and environment differences. The vegetative stages and six subdivisions of the reproductive stages are designated numerically with their common names in Table 1.
Table 1. Growth and development stages.
Each leaf stage is defined according to the uppermost leaf whose leaf collar is visible. The first part of the collar that is visible is the back, which appears as a discolored line between the leaf blade and leaf sheath. The characteristically oval-shaped first leaf is a reference point for counting upward to the top visible leaf collar as demonstrated in Figure 1.
Emergence may occur as rapidly as 4 or 5 days after planting in warm moist soil, or may take 3 weeks or more in cool soils. A new leaf will appear about every 3 days during early growth, while later leaves developing during warmer conditions may appear in 1 to 2 days. Full season hybrids in central Nebraska typically can produce 21 to 22 leaves. Earlier maturing hybrids will produce fewer leaves. The rate of development after pollination is given in Table 2. Bear in mind that development may be faster than suggested here under higher than normal temperatures or slower under lower than normal temperatures.
Table 2. Days after pollination for reproductive growth stages.