Influence of the genitors on the flowering of olive seedlings under forced growth

Olive breeding has been neglected for a long time due to its large juvenile period (JP). Previous works evidenced the possibility to shorten that period by forcing the growth of seedlings. However there is no data on the genetical control of the JP in olive. Seedlings from reciprocal crosses among 'Albequina', 'Frantoio' and 'Picual were forced in greenhouse under continuous light and 15-30 degrees C with fertirrigation during 7-8 months. After a short period in the lathouse the plants were moved to the open field under controlled irrigation. First field plantations were established in the spring of 1994 and 1995. By the second year, flowering reached 4% and 22% of the trees respectively and in the third year those values reached 47% and 55%. Among progenies, significant differences in the percentage of flowering were recorded. By the third year as a genitor, 'Arbequina' provides progenies that reached a maximum of 29% and 66% of flowering seedlings by the 2 (nd) and 3 (rd) years of field plantation respectively. Similar figures were 11% and 41% for 'Frantoio' and 25% and 56% for 'Picual' progenies. These results suggest some relation between the lenght of the non bearing period of the genitor and the lenght of the JP of their progenies.