Foliar application of boron to improve 'Hass' avocado productivity

Avocado is an edible crop with increasing economic significance. ‘Hass’ is the primary avocado cultivar, gaining high popularity among consumers and dominating the world industry. ‘Hass’ cultivation areas expand each year, but growers consistently report issues of irregular bearing and low yields. Leaf mineral analyses revealed that leaf boron (B) levels are significantly lower than the standard deficiency threshold in many avocado orchards in Israel. B deficiency is known to decrease vegetative growth and enhance environmental stress susceptibility and is suggested to impair pollen grain development and germination. In the present work, B sprays were carried out at the beginning and middle of the flowering season in orchards suspected of B deficiency. The experiments were conducted over 3 years in four different orchards in Israel’s Galilee region with varying concentrations of B products (B7000 and Nutrivant™). The effects on fruit-set and yield were evaluated, together with histologic examinations of the flower pistil. B-treated flowers exhibited higher levels of pollen germination. Some of the B treatments improved fruit set and final yield, but results were inconsistent across years and orchards. Further research is required to better understand the impact of B on fruit production and to develop an efficient protocol for B application in avocado orchards.