Study of self-incompatibility in some Iranian olive cultivars

Despite the profusion of flowers that develop on olive trees, only a few set fruit during the growing season and only about 1-2% of the fruit remains on the trees at maturity. Therefore, to maximize fruit set and yield, it is important for growers to understand the cross-compatibility between cultivars when planning to establish an olive orchard. This study was carried out in Shiraz, Fars Province, in 2005 and 2006 to identify the best pollinizers for Zard, Roghani, Fishomi and Shiraz olive cultivars. Flowers were pollinated using pollen from cultivars Dezfoul, Roghani, Zard, Shengeh, Shiraz, Fishomi and Fishomi-Roudbar and/or the flowers were self-pollinated or open-pollinated. Initial and final fruit set, fruit yield and self-incompatibility were assessed. Results showed that cultivars Zard and Fishomi are self-compatible, whereas Roghani and Shiraz are relatively self-incompatible (self-incompatibility index = 0.47 and 0.34, respectively). Cultivars Fishomi-Roudbar and Dezfoul were identified as suitable pollinizers for Roghani and Shiraz, respectively.