Arbosana Olive Is Self-Incompatible, but Inter-Compatible with Some Other Low-Vigor Olive Cultivars

Abstract

Trendy high-density olive fields are often monovarietal orchards, mostly using the cultivar Arbequina. However, Arbequina shows a strong self-incompatibility response, and its yields depend on wind cross-pollination, which is not always available. With the aim of finding suitable self-compatible cultivars that can replace Arbequina, we evaluated pollen–pistil interaction, fruit set and seed paternity in Arbosana under different pollination treatments: self-pollination, open-pollination and three cross-pollination treatments: × Arbequina, × Sikitita and × Koroneiki. All these cultivars are low-vigor cultivars suitable for high-density orchards, making them potential pollinizers for Arbosana. The results show that Arbosana is also self-incompatible with a strong reduction in fruit set due to a lower fertilization level caused by a strong inhibition of pollen tube growth in self-pollinated flowers. Seed-paternity analyses confirmed the self-incompatibility response of Arbosana and suggest that some fruit obtained in bagged shoots under self-pollination were, in fact, a product of cross-fertilization. In conclusion, we recommend against the use of Arbosana in large monovarietal orchards. On the contrary, good results were obtained under cross-pollination with Sikitita, Arbequina and Koroneiki pollen, allowing us to recommend them as pollinizers for Arbosana in appropriate pollination designs. This is the first time Arbosana self-incompatibility has been reported.