Articles
EFFECT OF AN AUTUMN APPLICATION OF CHLORMEQUAT ON REPRODUCTIVE BUD DEVELOPMENT, FRUIT SET AND PRODUCTION OF THE PEAR CV. DOYENNE DU COMICE
Article number
475_31
Pages
251 – 264
Language
Abstract
Chlormequat (1000, 2000, 3000 or 4000 mg/l) was applied as a foliar spray in autumn in two areas (Koue Bokkeveld – Site A and Elgin – Site B) to study its effect on reproductive bud development, fruit set and production of the pear cv.
Doyenné du Comice (Pyrus communis L.). Treatments were applied to six-year-old ‘Comice’ trees at site A (three weeks prior to natural leaf drop) and to 11-year-old ‘Comice’ trees at site B (a month prior to natural leaf drop). The quality of reproductive buds was determined in terms of the average number of bud scales and number of flowers per bud, as well as dry weight of ten flower buds per plot.
At full bloom, the length of the receptacle and pedicle of ten ‘king flowers’ per plot was measured.
The set potential was determined at the full bloom stage and the flower and fruit drop pattern was determined by counting fruit at ten-day intervals on tagged branches, starting at ten days after full bloom.
Final fruit set was recorded by counting the pears at 40 to 50 days after full bloom and it was expressed as a percentage of the number of initial flower clusters on the tagged branches.
The amount of vegetative growth was determined after shoot growth cessation (28/12/1995 and 8/01/1996 at site A and B, respectively) by recording the total shoot growth and the average number of shoots/100 cm branch unit on the tagged branches to obtain the corresponding average length per shoot.
At harvest (19–20/02/1996; site A and B, respectively) all fruits were weighed and production expressed as kg per cm trunk circumference, as measured 25 cm above ground level.
A random sample of ten fruit per replication was used to determine average fruit weight, length/diameter ratio and number of viable seeds.
Chlormequat improved flower bud quality in terms of average dry weight and number of flowers per bud.
There was a decrease in average receptacle and pedicle length of the ‘king flower’ at site B. Chlormequat-treated flowers also had a higher initial set potential and maintained this throughout the period of flower degeneration.
There was no significant change in the fruit drop pattern, although fruit set appeared to be higher in chlormequat – treated trees, especially at site B. There was an increase in fruit set and production after autumn chlormequat application.
Total shoot growth was significantly reduced after chlormequat treatment.
This was due to shorter shoot length, because the number of shoots was not significantly reduced.
Chlormequat did not significantly change
Doyenné du Comice (Pyrus communis L.). Treatments were applied to six-year-old ‘Comice’ trees at site A (three weeks prior to natural leaf drop) and to 11-year-old ‘Comice’ trees at site B (a month prior to natural leaf drop). The quality of reproductive buds was determined in terms of the average number of bud scales and number of flowers per bud, as well as dry weight of ten flower buds per plot.
At full bloom, the length of the receptacle and pedicle of ten ‘king flowers’ per plot was measured.
The set potential was determined at the full bloom stage and the flower and fruit drop pattern was determined by counting fruit at ten-day intervals on tagged branches, starting at ten days after full bloom.
Final fruit set was recorded by counting the pears at 40 to 50 days after full bloom and it was expressed as a percentage of the number of initial flower clusters on the tagged branches.
The amount of vegetative growth was determined after shoot growth cessation (28/12/1995 and 8/01/1996 at site A and B, respectively) by recording the total shoot growth and the average number of shoots/100 cm branch unit on the tagged branches to obtain the corresponding average length per shoot.
At harvest (19–20/02/1996; site A and B, respectively) all fruits were weighed and production expressed as kg per cm trunk circumference, as measured 25 cm above ground level.
A random sample of ten fruit per replication was used to determine average fruit weight, length/diameter ratio and number of viable seeds.
Chlormequat improved flower bud quality in terms of average dry weight and number of flowers per bud.
There was a decrease in average receptacle and pedicle length of the ‘king flower’ at site B. Chlormequat-treated flowers also had a higher initial set potential and maintained this throughout the period of flower degeneration.
There was no significant change in the fruit drop pattern, although fruit set appeared to be higher in chlormequat – treated trees, especially at site B. There was an increase in fruit set and production after autumn chlormequat application.
Total shoot growth was significantly reduced after chlormequat treatment.
This was due to shorter shoot length, because the number of shoots was not significantly reduced.
Chlormequat did not significantly change
Publication
Authors
K.Y. Theron, P. du Plessis, H.M. Griessel
Keywords
Cycocel, shoot growth
Online Articles (74)