ISHS


Acta
Horticulturae
Home


PubHort
Home


Login
Logout
Status


Help

ISHS Home

ISHS Contact

Search
 
ISHS Acta Horticulturae 596: VIII International Symposium on Pear

GROWTH OF CLARA FRIJS PEAR IN A NORDIC CLIMATE

Author:   M. Bertelsen
Keywords:   Pyrus communis, fruit expansion rate, fruit size, mean temperature, fruit density
DOI:   10.17660/ActaHortic.2002.596.135
Abstract:
Fruit growth of the pear cultivar Clara Frijs was studied under field conditions during four years, from 1997 to 2000. Every year, ten fruits were tagged and measured on 9-10 trees within the same mature planting. The trees were carrying different crop loads ranging from less than 1 fruit/cm trunk cross-sectional area (TCA) to more than 7 fruit/TCA, in which case the trees were extremely over-cropped. The majority of the trees, however, were hand-thinned and carried crop loads within the normal range. Full bloom date varied up to 14 days within the four-year period, and was found to be of large importance for fruit size in 2000 when bloom was at the earliest. The fruit expansion rate varied through the season from 0.43 mm/day up to 0.65 mm/day. Fruit expansion rate was highly responsive to changes in mean temperature in three of the four years. The correlation was not restricted to the first part of the season, but continued until onset of maturation. The magnitude of the temperature response, however, was not predictable and more years of recordings are needed to elucidate this aspect. Fruit expansion rate did not appear to be related to days after full bloom (DAFB). Fruits were capable of high expansion rates beyond day 100 AFB. A general and irreversible drop in the fruit expansion rates, however, was recorded shortly before harvest at onset of maturity.

Download Adobe Acrobat Reader (free software to read PDF files)

596_134     596     596_136

Websites www.pubhort.org/actahort/      www.actahort.org       www.pubhort.org       www.ishs.org       Hosted by KU Leuven LIBIS       ©ISHS