ABSTRACT
The objective of this study was to verify and confirm experimentally the reproductive system of the Portuguese pear (Pyrus communis L. cv. Rocha) through assessments of the amount and viability of pollen grains, the number of ovules per flower and pollen/ovule ratio, in addition to the quantification of the fruit set in different controlled pollination systems. The results show that cv. Rocha produced fewer pollen grains and ovules per flower than the cvs. Housui and Packham’s Triumph, which were used as pollen donor cultivars in this area. The average pollen/ovule ratio of the three cultivars was 17.015,05, which classifies them as xenogamic. The pollen grains of the cv. Packham’s Triumph showed the highest percentage of germination compared to ‘Housui’ and ‘Rocha’. The results of the controlled pollination treatments show that cv. Rocha present a high fruit set when cross-pollination occurs, even without the exogenous application of growth regulators. However, the application of a synthetic gibberellin promotes a significant increase in fruit set in open pollinated flowers, but its effect was variable in different years. The formation of stenospermocarpic fruits probably is stimulated with pollination and exogenous application of a synthetic gibberellin. We concluded that ‘Rocha’ pear is xenogamic and set a high fruit yield when properly pollinated with pollen from ‘Housui’ and ‘Packham’s Triumph’, and the application of gibberellic acid is an alternative in case of poor pollination .
Index terms
Pyrus communis; ‘Rocha’; fruit set; gibberellin; pollination
