VIABILITY AND IN VITRO GERMINABILITY OF POLLEN GRAINS OF OLIVE CULTIVARS GROWN IN DIFFERENT ENVIRONMENTS

Yield of olive orchard depends on many factors; among them potential male fertility plays a primary role in both self-fertile and self-incompatible cultivars. Genetic and environmental factors have been indicated as important factors affecting pollen grain viability and germinability. In this study these two parameters were investigated on fresh pollen grains collected from plants of the cultivars ‘Arauco’, ‘Arbequina’, ‘Coratina’, ‘Farga’, ‘Frantoio’, ‘Leccino’, ‘Leccio del Corno’, ‘Morchiaio’, ‘Morettini’, ‘Nevadillo’, ‘Nocellara’, ‘Sevillana Fina’, ‘Urano’. The cultivars were grown in Mendoza (Argentina), different localities of Buenos Aires (Argentina) and Tuscany (Italy). Viability was assessed by the fluorochromatic reaction with double coloration with fluorescein diacetate and propidium iodide. In vitro germinability was evaluated on pollen grains cultivated in droplets of H₃BO₃, Ca(NO₃)₂ and sucrose contained in petri dishes. Pollen grains showed different rates of viability and germinability in relation to cultivar and place of cultivation. The percentage of viable pollen grains consistently resulted higher than the rate of in vitro germinability. No linear correlation was found between the viability and germination rates.