What Causes Parthenocarpic Pods in Soybeans?
If you noticed empty soybean pods in 2024, you weren’t alone. A curious condition known as parthenocarpy popped up more than usual.
Soybean plants with fully parthenocarpic pods are easy to identify late in the season, appearing lush green with few or no pods.
Unfilled soybean pods form when something—be it genetics, weather or another factor—disrupts pollen production in the flower. After digging into the research, I
suspect cool flowering temperatures played a large role in 2024’s occurrences.
Let’s take a closer look at why this happened and what it might mean for your crops.
Plants with exclusively parthenocarpic pods are relatively easy to spot in late-season soybean fields. They are typically very green and bear few, if any, pods.
Various factors can cause parthenocarpic pods, including environmental influences like chemical residue or drift, soil fertility issues, plant mutations and, less commonly, viruses or insect damage.
Interestingly, 2024 appears to have seen a higher incidence of these unusual plants than prior years. I attribute this to the unusually cool temperatures during flowering.
The occurrence of parthenocarpic pods has been used to evaluate cold tolerance in soybeans, particularly in developing “cold tolerant” early maturing varieties designed for northern climates. Longer periods of cool temperatures at flowering mean more of these odd, unfilled pods.
If you observed parthenocarpic pods in 2024, there’s no need for concern. This phenomenon, like many field issues last season, is likely a one-off occurrence.
Parthenocarpic Pod Points to Ponder
Cool temperatures can cause the formation of parthenocarpic pods,
although for this plant it was more likely genetic mutation.
1. Increased Incidence in 2024: A higherthan-usual occurrence of parthenocarpic soybean pods was observed, likely due to cool temperatures during flowering, which disrupted pollen production.
2. Multiple Contributing Factors: While temperature played a major role, chemical residue, soil fertility issues, plant mutations, and even insect or virus damage can also contribute to parthenocarpy in soybeans.
3. Not a Major Concern: This phenomenon has been used to study cold tolerance in soybeans, but in 2024, it is likely a one-off event rather than an ongoing agronomic issue.
