Viability and in vitro germinability of pollen grains of olive cultivars and advanced selections obtained in Italy

Abstract

In the frame of a breeding programme of olive, started in 1971 and carried out at the Department of Horticulture of the University of Florence (Italy), 134 advanced selections are under evaluation. Viability and germinability have been evaluated on pollen grains collected from trees (11 advanced selections and four culti- vars, 'Carolea', 'Frantoio', 'Leccino'and 'Moraiolo') grown at Spoleto (province of Perugia). Pollen grains have been stored at different temperatures (-20°C, +4°C and +20°C) and for 7, 35 and 200 days from full bloom. Via- bility was assessed by means of fluorescence microscopy; in vitro germinability was evaluated on pollen grains cultivated in 10 different growing media. Pollen grains showed different rates of viability and germinability in relation to storage length, storage temperature, genotype and their interactions. Storage length had a statistical - ly significant effect both on pollen grain viability and germination. No linearcorrelation has been found between viability and germination rates. Some advanced selections showed levels of pollen grain viability and germina - bility comparable to those of cultivars used also as pollinizers.