Corn Growth and Development: Crop Staging

By Osler Ortez and Alexander Lindsey

One of the bottom-line activities in growing crops should be understanding and keeping track of crop growth and development. Crop growth is related to the increase in size. It is influenced by factors such as temperatures, water availability, stress, competition, and fertility. Crop development relates to the progress in stages, and temperatures primarily drive it.

Corn plants are first staged as vegetative (from emergence to tasseling) and then reproductive (from silking to physiological maturity). These vegetative or reproductive stages are assigned on a field basis when more than half of a subsample of plants are at the same stage. Despite different staging methods exist (e.g., horizontal leaf and leaf tip), the recommended is the Leaf Collar method for vegetative stages (V) and indicators of kernel development for reproductive stages (R) [Table 1].

Table 1. Vegetative and Reproductive Stages for corn. Adapted from Abendroth et al., 2011.

When it comes to crop management, one should focus on development as a more precise crop reference instead of growth. At later vegetative stages (after V10), younger leaves have often senesced, and the split-stalk approach may need to be taken to accurately stage plants (i.e., plants do not stay at the V12 stage until tasseling). This video shows staging using the split-stalk technique.

From planting to physiological maturity, plant structures initiate and grow at different stages (Figure 1). In the case of modern hybrids, it is common to see silks emerge (R1) before tassels fully emerged (VT) as this can improve pollination. Adverse conditions such as drought, heat, off label applications during any of these processes can negatively impact the crop and ultimately affect yields.

Figure 1. Corn growth and development from planting and germination (G) to physiological maturity (R6). Brown arrows indicate the primary period, and gray arrows indicate possible variations for each event. Source: Ortez et al., 2022 (Crop, Forage & Turfgrass Management, accepted, in production).

An adequate understanding of stages in corn is essential when planning different activities in the growing season—for example, fertilizer, herbicide, insecticide, and fungicide applications. Additionally, a good follow-through of corn staging can help understand when critical events occur, for example, drought stress linked to a reduction in kernel fill (i.e., kernel weight) towards the end of the season.