ISHS Acta Horticulturae 872: VIII International Symposium on Temperate Zone Fruits in the Tropics and Subtropics
FRUIT SET INFLUENCED BY THE OCCURRENCE OF PARTHENOCARPY IN ASIATIC PEAR TREE CULTIVARS IN TWO LOCATIONS IN SANTA CATARINA STATE, SOUTH BRAZIL |
| Authors: | I.D. Faoro, A.I. Orth |
| Keywords: | Pyrus pyrifolia var. culta, fruit set, seeds, anemophily, self-fertility |
| DOI: | 10.17660/ActaHortic.2010.872.35 |
| Abstract:
As a rule for commercial production of pears it is indicated using a high percentage of pollinizer varieties (from 10 to 20%) as its flowers produce a low amount of nectar, with a very low rate of sugar (10-15%). This makes the flowers of low attractiveness to pollinating insects. Due to the frequent yearly variation of winter chilling amount in the South of Brazil, the occurrence of non-coincidence of blooming between the target variety and its pollinizers is usual. Even so, quite frequently a reasonable fruit yeld occurs. In this study, we tested three forms of flower pollination: a) simply emasculation; b) self-pollinated flowers; c) hand-pollinated flowers. Just after pollination at open-field, the flowers were bagged in two ways: a) brown kraft paper bags; b) white fabric mesh bags. The pear varieties used were ‘Housui’ and ‘Kousui’ grown at two different climatic regions regarding the winter chilling in the South of Brazil: a) Caçador district (EECD), where around 1000 chilling units occur; and b) São Joaquim district (EESJ) with around 2000 chilling units - CU measured according to the Modified North Carolina Method. We did not detect anemophily or self-pollination or pseudo-compatibility among flowers. The fruit set was good to very good as an effect of parthenocarpic fruit formation in both locations. For the hand-pollinated flowers, as a result of the tight contact of the brush used for pollination of the stigma, the fruit set was higher. The fertility rate of the two cultivars tested was low to very low. | |
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