Israeli Researchers Use Gibberellin to Boost Young Avocado Tree Survival and Yields Amid Climate Stress
In response to extreme heatwaves that severely damaged young avocado trees, especially the popular 'Hass' variety, Israeli agricultural researchers have developed a treatment using the plant hormone gibberellin to improve tree survival and fruit yield. The 2020 May heatwave caused significant mortality among young avocado seedlings during their sensitive spring leaf replacement and flowering period. This led growers to seek solutions from the Ministry of Agriculture and Dr. Vered Yerichimovich of the Volcani Institute, who specializes in flowering control in subtropical trees.
Gibberellin, known to reduce flowering and promote leaf growth, was tested in field trials across several regions including Sharon, Shfela, and Gaza envelope. The hormone was sprayed on young avocado plots in autumn, resulting in reduced flower numbers but increased leaf retention, larger leaves with higher chlorophyll, and ultimately higher fruit yields the following season. Dr. Yerichimovich explained that although flowering was suppressed, the treatment increased the number of undeveloped inflorescences that could mature into fruit, and reduced fruit drop due to enhanced photosynthesis.
The research involved collaboration with Prof. Trine Paz-Kagan from Ben-Gurion University, Dr. Leo Weiner from the Ministry of Agriculture, and the company Gadot Agro. Remote sensing via drones combined with machine learning models allowed precise monitoring of canopy density, leaf cover, and chlorophyll content, confirming denser canopies in treated trees. This technology shows promise for accurate avocado orchard management.
Avocado cultivation in Israel covers about 140,000 dunams with 7,000-10,000 dunams newly planted annually, making it a key agricultural export surpassing citrus fruits. The treatment's economic importance is high, especially as many orchards are located in border areas like northern Israel and Gaza envelope, adding national significance. Further studies led by Dr. Noam Elkan and Dr. Marie-Daphné Yellin found additional benefits of gibberellin treatment, including improved fruit quality, reduced fruit skin cracking, and lower fungal infections.
The gibberellin treatment is cost-effective, involving two low-concentration sprays, and is currently recommended for young orchards up to 3-4 years old. Ongoing research aims to assess its effects on mature trees and whether continued application can enhance yields in weaker years. The findings are set for publication in a scientific journal, and the treatment is being integrated into agricultural practice to mitigate climate-related damage to avocado crops in Israel.
