Site, vine state and responsiveness to the application of growth regulator fruitsetting agents

• Autores: John A. Considine, G. Cass
• Localización: Australian journal of grape and wine research, ISSN 1322-7130, Vol. 15, Nº 1, 2009, págs. 48-58
• Idioma: inglés
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• Resumen

  • Background and Aims: This study was initiated to investigate local problems in obtaining consistent fruit-setting responses to a recommended treatment combination of gibberellic acid (GA3) and (2-chloroethyl)-trimethyl ammonium chloride (CCC), with vineyard managers returning to more traditional methods of either cincturing or applying 4-chlorophenoxy acetic acid (4-CPA).

    Methods and Results: Five vineyard study sites located in the Chittering�Bindoon region of Western Australia were characterised by multivariate analysis using measures of vegetative and reproductive biomass. Two experiments were carried out in the vineyard to compare responses to combinations of GA3 and CCC. 4-CPA was used as an industry control. Bunch number was used as a novel covariate to adjust responses to individual vine and site factors. Berry volume increased in all vines and sites treated with GA3, irrespective of timing, but dry matter yield increased only in the youngest vineyards. The only site to show a significant response to CCC application was that with the highest vegetative biomass.

    Conclusions: We conclude that site and management factors rather than growth regulator type, concentration or timing determined yield responsiveness (sugar production).

    Significance of the Study: This study demonstrates a strong physiological and environmental effect on response to growth regulator application, reinforcing the importance of developing site-specific management practices. It shows how multivariate techniques may be used to characterise and compare vineyards, and also, how analysis of covariance using a new parameter, bunch number, may be used to enhance statistical of analysis of field experiments.