Big Seeds vs. High Yields - Does Seed Size Actually Matter at Harvest?
Many growers assume that larger seeds automatically lead to higher crop yields, but research suggests the relationship is not that straightforward.
While the basic yield formula—yield equals the number of seeds per acre multiplied by the weight of each seed—appears to support that idea, several biological and environmental factors influence the final outcome.
According to Dennis Egli, Professor Emeritus at the University of Kentucky, one of the most important considerations is whether seed size differences are caused by genetics or by growing conditions.
Seed size varies dramatically among crop species. For example, canola produces very small seeds, while corn generates much larger ones. Even within the same crop, varieties can differ significantly in seed size due to genetic traits.
However, larger seeds do not necessarily result in greater yields. In many cases, genetic differences in seed size are linked to how quickly seeds develop rather than the total amount of grain a crop produces.
Varieties with larger seeds often achieve that size through faster seed growth, but this can reduce the total number of seeds produced per acre.
Conversely, plants that develop smaller seeds may compensate by producing more seeds. As a result, overall yield frequently remains similar despite differences in individual seed size.
There are situations where larger seeds can contribute to higher yields. This typically occurs when seed size increases because of a longer seed-filling period rather than a faster growth rate.
When plants have more time to accumulate nutrients and carbohydrates in developing seeds, both seed weight and total productivity can improve.
Environmental conditions often have an even greater influence on final yield than genetics. Once seed numbers are established, factors such as rainfall, temperature, disease pressure, and water availability determine how well seeds fill.
Favorable weather during seed development can increase seed weight and boost yields, while stress conditions can have the opposite effect.
Studies in soybeans have shown that just a few days of water stress during seed filling can significantly reduce both seed size and overall yield.
Ultimately, crop productivity depends on a balance between seed number, seed size, genetics, and environmental conditions throughout the growing season.
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