ISHS Acta Horticulturae 587: International Symposium on Asian Pears, Commemorating the 100th Anniversary of Nijisseiki Pear
TEMPERATURE DEPENDENCE OF ENDODORMANCY DEVELOPMENT IN FLOWER BUDS OF 'KOUSUI' JAPANESE PEAR AND A MODEL FOR ESTIMATING THE COMPLETION OF ENDODORMANCY |
| Authors: | T. Sugiura, H. Kuroda, H. Honjo, D. Ito |
| Keywords: | Pyrus pyrifolia, model, Chill Unit, developmental rate, developmental stage, DVR, DVI |
| Abstract:
Temperature dependences of endodormancy development of flower buds of ‘Kousui’ Japanese pear (Pyrus pyrifolia Nakai) trees were investigated and a model for estimating the time of endodormancy completion was developed. Potted trees were placed in chambers adjusted to various temperatures for various hours in each experiment. Chilling for 750 hours at 0~6oC was necessary to complete endodormancy. The chilling at 9oC needed 1160 hours, while at 12oC and -6oC the endodormancy did not complete. Chilling at -3oC is about 1/2~1/3 times as effective as 6oC. Forcing above 21oC negated previously accumulated chilling. In order to estimate the date of endodormancy completion in the orchard, a developmental rate (DVR) model describing the relationship between the endodormancy developmental rate and the temperature was developed using these results. Endodormancy completion dates in the open field were estimated by applying observed hourly temperatures to the model. The estimated dates agreed well with the dates in the open field determined by the forcing experiment. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
