Comparison between two pollen quality evaluation methods and germination in olive (Olea europaea L.)

In 2006 and 2007, the quality of pollen grains has been investigated in four Italian olive (Olea europaea L.) cultivars: ‘Ascolana Tenera’, ‘Cazzinicchio’, ‘Cima di Melfi’ and ‘Coratina’. Grains quality was estimated by using two different methods, acetic carmine (stainability) and fluorescein diacetate (viability), in comparison with germination. Acetic carmine and fluorescein diacetate gave statistically different data, i.e., 90.2 vs. 58.1%, whereas the mean germination value was only 48.0%. Acetic carmine always showed the highest values but also stained heat-killed pollen grains with a non-significant difference between heat-killed and stainable grains. Significant differences in acetic carmine and fluorescein diacetate values were observed among cultivars. ‘Cima di Melfi’ showed the highest percentage of stainable and viable pollen grains. Finally, fluorescein diacetate and germination were significantly correlated with a high R2 (0.862, P≤0.001).