Enhance Plant Growth with Biologicals
Bigger, faster, stronger – that’s generally the goal when it comes to crop production. More robust, vigorous plants have several advantages: they can outcompete pests vying for the same resources, are generally more resilient when faced with in-season stresses and have a better opportunity to build yield. While plant growth often depends on weather factors that are hard to predict, biologicals can help give crops an upper hand.
How Do Biologicals Support Crop Growth?
Plant growth regulators (PGRs) are a class of biologicals that influence plant growth. They can be synthetic or natural chemicals that mimic or boost plant hormones to affect specific physiological processes within a plant, including:
• Germination
• Root growth
• Prevention or promotion of stem elongation
• Flowering
• Plant senescence
• Fruit ripening
PGRs can stimulate or inhibit plant growth to support crop development or protect crops during stress. A PGR can affect different crop growth stages depending on its active ingredients and even the ratio of those active ingredients relative to each other. For example, Ascend2® PGR contains an auxin-dominant ratio of three plant hormones and is optimal for in-furrow application in corn. Meanwhile, its foliar counterpart, Ascend® SL PGR, has the same active ingredients, with a slightly higher rate of cytokinin to support vegetative and reproductive growth.
Common Plant Growth Regulators
There are many classes of PGRs, but here are five of the most common ones used in agriculture.
1. Auxins
Auxin is a plant hormone that affects several cellular processes, including root formation and growth. It is often the main active ingredient in rooting compounds for horticultural crops to accelerate root initiation, improve rooting uniformity and increase the number of roots produced.
Auxin has similar effects in row crops, making it an excellent early-season biological for promoting root health. Research has shown that an in-furrow auxin application can increase lateral root growth, while foliar applications have demonstrated an increase in stem diameter, number of leaves per plant, leaf area, total biomass and increased yield in corn.1,2
2. Cytokinins
Cytokinins influence cell division in plants, helping to regulate plant growth and development. Like auxins, they can contribute to faster root growth and help increase leaf surface area. They also can contribute stress tolerance benefits to plants and may help delay senescence. Research demonstrates that kinetin, a cytokinin in Ascend SL PGR, can increase the biomass, chlorophyll content and concentration of stress-fighting amino acids in corn seedlings.3
3. Gibberellic Acid
Gibberellic acid stimulates cell division and elongation in plants and is crucial for the seed germination process. It helps break seed dormancy and can help accelerate germination and crop emergence, which can be particularly beneficial for early-planted crops. Gibberellic acid has also been shown to improve corn growth rate and leaf area when applied with auxin at the V4-V6 growth stage, as well as ear length and number of kernels per row when applied at flowering.4
4. Ethylene
Ethylene is a gas that promotes or inhibits plant growth depending on its concentration and/or application timing. It can induce flowering, leaf drop and senescence in crops at high levels and is commonly used to accelerate fruit ripening in specialty crops. Plants often increase ethylene production in response to stress.
5. Abscisic Acid
Abscisic acid generally functions as a plant-growth inhibitor, which can benefit plants in stressful growing conditions. For example, abscisic acid may induce bud dormancy to help a plant survive a harsh environment. It also can prevent a seed from germinating if soil conditions aren’t ideal. Abscisic acid also may play a role in plant stomata closure to conserve water in drought conditions.
Find Verified Products
Biologicals, including plant growth regulators, can play a crucial role in crop development. But there are a lot of biologicals on the market that may carry lofty claims. WinField® United recognized a need for transparent biological product information, so we developed the WinField United BioVerified™ designation. Products with the designation help simplify biological recommendations and are rated against four key metrics: product uniqueness, agronomic performance, operational compatibility and economic return. Choosing a product with the WinField United BioVerified designation can streamline decision-making and give you more confidence in your product choices.
Plant-growth-enhancing biologicals with the WinField United BioVerified designation include PGRs in the Ascend portfolio:
• Ascend2 PGR
• Ascend SL PGR
• Ascend ST3® PGR
These products contain optimized ratios of auxin, gibberellic acid and cytokinin to support early and late-season crop growth and development. Ascend2 PGR and Ascend ST3 PGR are patented technologies, making them unique in the biologicals market. Consult your WinField United retailer for more information about how these products can help support your yield goals this season.
1 Sible, C. (2019). Plant growth regulators and biostimulants for use in varying management systems to improve corn grain yield. University of Illinois graduate theses.
2 Amin, A. A., Rashad, E. S. M., & Gharib, F. A. E. (2006). Physiological responses of maize plants (Zea mays L.) to foliar application of morphactin CF125 and Indole-3-butyric acid. Journal of Biological Science, 6, 547-554.
3 Xu, L., Li, P., Wang, Y., Guo, X., & Zhao, X. (2010). Effect of exogenous cytokinins on growth, activities of antioxidative enzymes and proline content in corn seedlings (Zea mays L.) under cadmium stress.
4 Ghodrat, V., Rousta, M. J., Tadaion, M. S., & Karampour, A. (2012). Yield and yield components of corn (Zea mays L.) in response to foliar application with indole butyric acid and gibberellic acid. Am Eurasian J Agric Environ Sci, 12, 1246-1251.
All photos are either the property of WinField United or used with permission.
© 2025 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years and to be mindful of how such agronomic conditions could impact results. Ascend, Ascend2, BioVerified, ST3 and WinField are trademarks of WinField United. All other trademarks are the property of their respective owners.
How Do Biologicals Support Crop Growth?
Plant growth regulators (PGRs) are a class of biologicals that influence plant growth. They can be synthetic or natural chemicals that mimic or boost plant hormones to affect specific physiological processes within a plant, including:
• Germination
• Root growth
• Prevention or promotion of stem elongation
• Flowering
• Plant senescence
• Fruit ripening
PGRs can stimulate or inhibit plant growth to support crop development or protect crops during stress. A PGR can affect different crop growth stages depending on its active ingredients and even the ratio of those active ingredients relative to each other. For example, Ascend2® PGR contains an auxin-dominant ratio of three plant hormones and is optimal for in-furrow application in corn. Meanwhile, its foliar counterpart, Ascend® SL PGR, has the same active ingredients, with a slightly higher rate of cytokinin to support vegetative and reproductive growth.
Common Plant Growth Regulators
There are many classes of PGRs, but here are five of the most common ones used in agriculture.
1. Auxins
Auxin is a plant hormone that affects several cellular processes, including root formation and growth. It is often the main active ingredient in rooting compounds for horticultural crops to accelerate root initiation, improve rooting uniformity and increase the number of roots produced.
Auxin has similar effects in row crops, making it an excellent early-season biological for promoting root health. Research has shown that an in-furrow auxin application can increase lateral root growth, while foliar applications have demonstrated an increase in stem diameter, number of leaves per plant, leaf area, total biomass and increased yield in corn.1,2
2. Cytokinins
Cytokinins influence cell division in plants, helping to regulate plant growth and development. Like auxins, they can contribute to faster root growth and help increase leaf surface area. They also can contribute stress tolerance benefits to plants and may help delay senescence. Research demonstrates that kinetin, a cytokinin in Ascend SL PGR, can increase the biomass, chlorophyll content and concentration of stress-fighting amino acids in corn seedlings.3
3. Gibberellic Acid
Gibberellic acid stimulates cell division and elongation in plants and is crucial for the seed germination process. It helps break seed dormancy and can help accelerate germination and crop emergence, which can be particularly beneficial for early-planted crops. Gibberellic acid has also been shown to improve corn growth rate and leaf area when applied with auxin at the V4-V6 growth stage, as well as ear length and number of kernels per row when applied at flowering.4
4. Ethylene
Ethylene is a gas that promotes or inhibits plant growth depending on its concentration and/or application timing. It can induce flowering, leaf drop and senescence in crops at high levels and is commonly used to accelerate fruit ripening in specialty crops. Plants often increase ethylene production in response to stress.
5. Abscisic Acid
Abscisic acid generally functions as a plant-growth inhibitor, which can benefit plants in stressful growing conditions. For example, abscisic acid may induce bud dormancy to help a plant survive a harsh environment. It also can prevent a seed from germinating if soil conditions aren’t ideal. Abscisic acid also may play a role in plant stomata closure to conserve water in drought conditions.
Find Verified Products
Biologicals, including plant growth regulators, can play a crucial role in crop development. But there are a lot of biologicals on the market that may carry lofty claims. WinField® United recognized a need for transparent biological product information, so we developed the WinField United BioVerified™ designation. Products with the designation help simplify biological recommendations and are rated against four key metrics: product uniqueness, agronomic performance, operational compatibility and economic return. Choosing a product with the WinField United BioVerified designation can streamline decision-making and give you more confidence in your product choices.
Plant-growth-enhancing biologicals with the WinField United BioVerified designation include PGRs in the Ascend portfolio:
• Ascend2 PGR
• Ascend SL PGR
• Ascend ST3® PGR
These products contain optimized ratios of auxin, gibberellic acid and cytokinin to support early and late-season crop growth and development. Ascend2 PGR and Ascend ST3 PGR are patented technologies, making them unique in the biologicals market. Consult your WinField United retailer for more information about how these products can help support your yield goals this season.
1 Sible, C. (2019). Plant growth regulators and biostimulants for use in varying management systems to improve corn grain yield. University of Illinois graduate theses.
2 Amin, A. A., Rashad, E. S. M., & Gharib, F. A. E. (2006). Physiological responses of maize plants (Zea mays L.) to foliar application of morphactin CF125 and Indole-3-butyric acid. Journal of Biological Science, 6, 547-554.
3 Xu, L., Li, P., Wang, Y., Guo, X., & Zhao, X. (2010). Effect of exogenous cytokinins on growth, activities of antioxidative enzymes and proline content in corn seedlings (Zea mays L.) under cadmium stress.
4 Ghodrat, V., Rousta, M. J., Tadaion, M. S., & Karampour, A. (2012). Yield and yield components of corn (Zea mays L.) in response to foliar application with indole butyric acid and gibberellic acid. Am Eurasian J Agric Environ Sci, 12, 1246-1251.
All photos are either the property of WinField United or used with permission.
© 2025 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years and to be mindful of how such agronomic conditions could impact results. Ascend, Ascend2, BioVerified, ST3 and WinField are trademarks of WinField United. All other trademarks are the property of their respective owners.
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