FERTILITY PROBLEMS IN CV. “ANTONIO ERRANI”: STIGMA-POLLEN INTERACTION

Cultivar “Antonio Errani”, selected in 1975 by our Department, was recently introduced in different cultivation areas in Italy. This cultivar is endowed with noteworthy organoleptic and commercial characteristics, but in some environments it is affected by poor and irregular fruiting. In the present study, some aspects of the floral biology of this variety were studied, in order to investigate possible causes of this infertility. Research focused on observation of compatibility and morphological analysis of the micro-gametophyte (characterization of pollen grain shape, viability and germination ability) and the macro-gametophyte (morpho-anatomic analysis of stigma structure by Scanning Electron Microscope observations). Directly on the stigmatic surface, observations were also carried out on pollen-pistil interaction, pollen retention on the stigma and germination ability. Moreover the pollen tube elongation in the style up to the ovary was observed. Results showed no anomaly involving the micro-gametophyte. Self-compatibility of the variety was confirmed, but poor pollen retention on the stigma was found, together with slow elongation of the pollen tube up to the ovary. Scanning Electron Microscope observations revealed early degeneration of stigmatic papillae, which were seen to be collapsed and therefore unable to retain pollen grains.