ISHS Acta Horticulturae 587: International Symposium on Asian Pears, Commemorating the 100th Anniversary of Nijisseiki Pear
STUDIES ON THE CAUSES OF FLORAL BUD ABORTION OF JAPANESE PEAR (PYRUS PYRIFOLIA) IN SOUTHERN BRAZIL |
| Authors: | J.L. Petri, G.B. Leite, Y. Yasunobu |
| Keywords: | bud abortion, Nashi, dormancy. |
| Abstract:
The Japanese pear was established as a commercial crop in South of Brazil in 1980. Yields produced since then have fluctuated widely depending on the climatic conditions in the winter and occurrence of the disorders affecting the floral bud. The affected bud produces reduced flower numbers in the clusters. Occurrence of disorder varies greatly between cultivars, seasons and locations, the cvs. Nijisseiki and Housui are the ones that have been presenting the highest occurrence, mainly in the areas with smaller intensity of cold in the winter. There are reports of a similar disorder affecting Nashi production in New Zealand, where it is known as “budjump”. In Brazil the problem is known as bud abortion but there has been no information of the causes nor the control methods. The experiments were conducted for three years to study the incidence and possible causes of the disorder. The studies are addressed for the occurrence time, formation of the floral primordia, concentration of water in the branches, variation of the amount of chilling hours, fluctuation of temperatures and effect of cultural practices. The results showed that the bud abortion intensified just before flowering, presenting normal floral primordia at the beginning of autumn. The number of flowers per cluster increased with the increase of the chilling hours which also reduced the percentage of bud abortion. Trees that received 1,440 chilling hours did not present the disorder and they had more flowers per cluster. Temperatures of 24oC at intervals of 15 days did not increase the bud abortion, when the tree received 1,440 chilling hours. The concentration of the water in the branches and the covering of the tree with cloth did not influence the incidence of bud abortion. The practice of girdling showed a tendency to reduce the problem in two or more years. The results evidenced that a relationship exists between bud abortion and the inadequate chilling during the dormancy period. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
