CHILLING EFFECT ON INHIBITION REMOVAL IN KIWIFRUIT DORMANT LATERAL BUDS

Two year old ownrooted plants of the staminate cv. ‘Tomuri’ (Acti nidia deliciosa Chev.) grown in containers were chilled in a 5.5°C cold chamber in darkness after leaf fall, while others remained outdoors.
At ten-fifteen day intervals from December 5 through February 14, three plants from each treatment were transferred into a forcing chamber at 23°C, with 12h of light.

At the same sampling times, single-node cuttings taken from the plants on December 9 and stored in a cold chamber at 5.5°C in the dark were also forced.

Single-node cuttings were able to reach advanced phenological stages even with a limited amount of chilling, confirming previous findings on the weak endogenous dormancy of Kiwifruit buds.
Chilling seems to be important, however, for removing inhibition due to the entire plant or to the shoot.
The bud breaking percentage of entire plants in fact increased progressively in response to chilling up to 1 200 C.U.. The number of fertile shoots developing from entire plants also proved positively influenced by the amount of chilling received by the buds (1 000 C.U.).

For the same C.U. level, the most rapid bud breaking was observed in isolated buds and the slowest in those of plants kept at 5.5°C. Buds of plants left outdoors initially showed an intermediate response to forcing and subsequently followed a similar behaviour to the isolated buds, probably when correlative inhibitions had been overcome.

I International Symposium on Kiwifruit

P. Guerriero, G. Scalabrelli, G. Grazzini

https://doi.org/10.17660/ActaHortic.1990.282.7