Many people observe similarities between sorghum and corn, leading to questions about their relationship. These two plants, both widely cultivated globally, share visual characteristics and some agricultural uses. Understanding their distinct biological classifications and unique attributes clarifies why they are often grouped together yet serve different roles in agriculture and industry.
A Shared Family Tree
Both corn (Zea mays) and sorghum (Sorghum bicolor) belong to the Poaceae family, the grass family. This classification places them alongside other cereal grains like wheat and rice. While they share this broad family lineage, corn is classified under the genus Zea, and sorghum is in the genus Sorghum. This taxonomic distinction shows they are related by a common ancestor, but not as closely as different varieties of corn, which are all Zea mays. Both genera are part of the PACMAD clade, a major evolutionary group, illustrating their shared, distant genetic heritage.
Similarities in Appearance and Growth
The visual resemblances between sorghum and corn can cause confusion, particularly during early growth stages. Both plants exhibit a tall, stalk-like growth habit with broad leaves, making them appear similar in fields. In their vegetative stages, distinguishing young sorghum from young corn can be challenging even for experienced observers. Both crops develop fibrous root systems, which anchor them and absorb nutrients and water from the soil. As cereal crops, both are cultivated for their grains and biomass.
Distinctive Features and Applications
Morphology and Environmental Adaptations
Despite their superficial similarities, corn and sorghum possess clear distinctions in their morphology and environmental adaptations. Corn produces large, single ears where its kernels develop, whereas sorghum forms a dense, panicle-like seed head at the top of its stalk. Sorghum leaves often have serrated or “scratchy” edges, while corn leaves are generally smooth. Sorghum plants also tend to produce more tillers, or side shoots, compared to corn.
Sorghum exhibits greater drought and heat tolerance compared to corn, making it a resilient crop in arid and semi-arid regions. This resilience stems from mechanisms like waxy leaf coatings that reduce water loss, leaves that roll to conserve moisture, and a finely branched root system that efficiently absorbs water. Sorghum can also enter a dormant state during drought and resume growth when moisture becomes available. In contrast, while corn is adaptable to diverse climates, it requires more consistent water for optimal growth.
Applications
Their applications also diverge, reflecting their unique properties. Corn is a versatile crop used for human food, including sweet corn, cornmeal, tortillas, and polenta, and as an ingredient in sweeteners and starches. It is also used for animal feed and in the production of ethanol and industrial materials like plastics and adhesives. Sorghum is valued for its gluten-free properties, making it suitable for food products and brewing. It is also used for animal feed, ethanol production, forage, and non-food items such as syrup and brooms.