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Faoro I.D.,Epagri Cacador Experimental Station and Uniarp | Orth A.I.,Federal University of Santa Catarina
Acta Horticulturae | Year: 2011

We evaluated the production of nectar and the content of total soluble solids (TSS) of nectar in different Japanese pear cultivars at two locations in southern Brazil. We observed variation in nectar production and in the TSS content of the nectar between years, cultivars and different flower phenological stages (3FX). The nectar production potential (with bagging of the flowers) was greater than that of nectar standing crop (no bagging of flowers) and begins at stages 3F3 and 3F4, respectively, when the flowers are at the balloon stage or newly opened flowers, and usually ends at stage 3F7, when all the anthers are darkened but petal drop has not occurred yet. Higher daily production of nectar (2.6amp;∼6.3 amp;μl/flower) and a higher average TSS content in the nectar (5.3amp;∼15.4amp;°Brix), typically occurs at stages 3F5 and 3F6. Due to the low TSS content, the attraction of the flowers of these pear cultivars to insect pollinators is probably mainly through its pollen resource. Source


Faoro I.D.,Epagri Cacador Experimental Station and Uniarp | Orth A.I.,Federal University of Santa Catarina
Acta Horticulturae | Year: 2011

Pear flowers produce nectar with very low amounts of sugar (10-15°Brix). This makes the flowers less attractive to pollinating insects and it is necessary to use a higher percentage of pollinizer cultivars (from 10 to 20%) than in apple orchards. Due to the frequent yearly variation of winter chilling amount in southern Brazil, non-coincidence of the blooming period between the crop cultivar and its pollinizers is common. Even so, quite frequently a reasonable fruit yield is observed. To study this fact we tested different methods of pollination and emasculation in two pear cultivars, 'Housui' and 'Kousui', in two different climatic regions in the south of Brazil, regarding the winter chilling: a) Caçador district (EECD), where around 1000 chilling units per season occur; and b) São Joaquim district (EESJ) with around 2000 chilling units. When flowers were hand-pollinated, fruit set was higher and fruit contained a higher number of seeds per fruit. The fruit setting of 'Housui' was greater in the colder site (São Joaquim) or in years with a higher amount of cold hours during the vernalization period. Both cultivars presented a high rate of parthenocarpic fruit, and also produced fruit, normally, by cross-pollination (xenogamy), but did not produce fruit by autogamy. The region with milder winter weather (EECD) induced a higher rate of parthenogenesis. The fertility of 'Housui' was low in EECD and high in EESJ. The fertility of 'Kousui' was very low and produced low number of seeds per fruit. After emasculating, the flowers were no longer attractive to pollinators. Source


Faoro I.D.,Epagri Cacador Experimental Station and Uniarp | Orth A.I.,Federal University of Santa Catarina
Acta Horticulturae | Year: 2015

This study aimed to evaluate the amount of visits of the main insect pollinators during flowering period in orchards of three Japanese pear cultivars and at two different locations and years with different climates in southern Brazil: Caçador (CD) and São Joaquim (SJ). During the flowering period, at 9 am and 3 pm, three trees of each cultivar were randomly chosen and the number of potentially pollinating insects per tree was quantified for a period of 3 min. In Caçador, the number of bees was also quantified on the ruderal plants inside the orchard. The highest numbers of flower visits were observed in the afternoon (3 pm), although the amount of pollinating insects in pear, both in the warmer climate region (CD) as in the colder climate region (SJ), is considered low according to the literature. Ruderal plants (white clover and dandelion, among others) with high sugar content in nectar and which grow between the tree rows attract more honey bees than pear tree flowers. In São Joaquim, in the first evaluation year, we did not detect significant nectar secretion and pollinating insects were only attracted to flowers by its pollen. It is necessary to install a larger number of honey bee hives per area to improve adequate pollination in pear orchards. Source


Faoro I.D.,Epagri Cacador Experimental Station and Uniarp | Orth A.I.,Federal University of Santa Catarina
Acta Horticulturae | Year: 2015

The presence of pollinating insects was identified in three Japanese pear cultivars ('Housui', 'Kousui' and 'Nijisseiki') at two locations with different climatic conditions: a) Caçador with 550UF, and b) São Joaquim with 938UF, both locations are in State of Santa Catarina, Brazil. In Caçador occurred a greater diversity of insect pollinators due to the proximity of the orchard area with a native forest area. In São Joaquim only two insects pollinating species of pear trees were identified. We recorded melitophilly as the primary pollination syndrome and cantarophilly as a secondary pollination syndrome in pear trees. This latest is probably the first record in the pear culture in Brazil, and is due to presence of the beetle Astylus quadrilineatus (Germar, 1824) (Order: Coleoptera; Family: Melyridae). Source

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