As California cherry growers approach bloom, weather conditions and flower timing will play a major role in determining fruit set and overall yield. In today’s Growing Edge segment, Poli Francescatto, Valent BioSciences Global Technical Development Manager for Plant Growth Regulators (PGRs), discussed how plant growth regulators like ReTain® PGR for California can help growers navigate the critical bloom window in cherries.
Francescatto noted that cooler conditions and adequate chilling have positioned many orchards for a strong bloom. However, bloom conditions remain unpredictable. Some orchards may need help improving fruit set, while others could face heavy crop loads requiring thinning. Valent offers tools to support both objectives depending on the situation.
ReTain contains AVG, an active ingredient that blocks ethylene production in plant tissues. Ethylene is responsible for flower senescence, fruit maturation, and fruit drop. By reducing ethylene levels during bloom, ReTain helps extend flower longevity, giving blossoms more time to be pollinated and fertilized.
This extended bloom window can be especially valuable during challenging weather. In hot conditions, ethylene production increases, potentially shortening flower viability. Conversely, during cold or rainy periods when bee activity is limited. ReTain can provide an extra one or two days for pollination to occur.
Timing is critical when using PGRs in cherries. Francescatto emphasized that ReTain should be applied during a specific window, typically from popcorn stage up to about 20 percent open bloom for sweet cherries, to target flowers at their most responsive stage.
As cherry bloom approaches, growers are encouraged to evaluate bud fertility, monitor weather forecasts, and plan applications carefully. With proper timing, ReTain can serve as a valuable tool to support fruit set and help cherry growers maximize yield potential.
For more information, visit valent.com/ReTainCA.
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