MANAGEMENT SYSTEMS FOR TISSUE CULTURE PROPAGATED APPLE TREES

Tissue culture (TC) propagated ‘Gala’ and ‘Triple Red’ apple trees grown at low density (3.7 X 4.9 m = 561 trees/ha) and high density (1.8 X 4.9 m = 1121 trees/ha) were treated, beginning the 3rd growing season, with plant growth regulators (PGR’s) to control tree size and induce early flowering.
Tree size of both cultivars was reduced by the triazole PGR’s, paclobutrazol and uniconazole.
Several triazole treatments increased numbers of flowers and fruit on the slow-to-flower ‘Triple Red’ trees in 1988 (5th season), but some had detrimental effects on flowering and fruiting of ‘Gala’ which flowers precociously and profusely.
High density plantings produced higher yields/ha than low density plantings whereas low density produced more fruit/ tree.
Uniconazole applied as a trunk drench or as a trunk paint increased net photosynthesis, chlorophyll content, stomatal conductance and specific leaf weight.
TC and budded control trees did not differ for these parameters.

Symposium on Integrated Fruit Production

G.L. Steffens, R.H. Zimmerman

https://doi.org/10.17660/ActaHortic.1990.285.16