Cycocel Effectively Retards Nursery Height Grwoth of Eucalyptus Grandis

Sometimes nursery stock must be sown earlier or held later than desired. How to limit seedling growth without affecting outplanting performance a serious problem for nurserymen. Soil drenches containing Cycocel, a growth retarding chemical, kept Eucalyptus grandis seedlings from growing too tall during an extended nursery season, and subsequent field growth was not retarded significantly. Growth retardants are synthetic compounds, temporarily restricting height growth without deforming plants. Cell division, and probably cell elongation, slow down just below the terminal growing point, resulting in compact plants with shorter stem sections between leaves. Unlike growth inhibitors, retardants should not reduce the number of leaves or alter stem dominance. Cathey 1 published a complete review of growth retardants. We tested Cycocel and another retardant, Phosfon, as soil drenches and foliar sprays (table 1) . Phosfon retards a limited number of species, acts at low concentrations, and persists in the soil. It was ineffective in our tests. In contrast, Cycocel leaches readily and retards numerous species, but many species require high concentrations. We found it effective on this species as a drench. Both products are sold to produce compact growth of potted ornamentals.

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Author(s): George F. Meskimen

Publication: Tree Planters' Notes - Volume 18, Number 4 (1967)

Volume: 18

Number: 4