Improving yield and quality of 'Merlot' with application of a mixture of plant hormones
Due to the constant need for improvement in the quality of grape bunches, we note the increasing use of bioregulators in modern viticulture. Composed of low concentrations of plant hormones, they act in different cellular structures, causing physiological changes in plants. This study aimed to evaluate the effects of bioregulator Stimulate® on morphological and physical-chemical characteristics of grapes cultivar 'Merlot'. Stimulate® doses of 0.1, 0.2 and 0.3% were tested and applied once in full bloom (70-80% of flowers open) during the 2011-2012 season. All treatments received adjuvant Natur'l Oil 0.1%. The following were analysed: number of berries per bunch, rachis mass, berry mass, soluble solids, titratable acidity, pH, berry diameter, length and width of bunches, bunches mass, productivity anthocyanins and polyphenols. The pH, total acidity, berry diameter and length of bunches did not adjust significantly to a regression model. As the Stimulate® dose increased, there was a linear increase in the diameter of the berries. For berries number per bunch, rachis mass and bunch width a quadratic polynomial regressions with minimum points was used. Positive quadratic polynomial regressions were adjusted significantly to the berries and bunches mass, soluble solids and productivity. It was concluded that applying Stimulate® doses between 0.1% and 0.2%, promoted increased productivity, bunch mass, berry mass and higher anthocyanins amount. The dose of 0.3% provides greater accumulation of soluble solids as well as higher content of polyphenols to the detriment of lower productivity.
Mario, A.E., Fagherazzi, A.F., Turmina, A.G., Lerin, S., de Souza, D.S., Rufato, L. and Andriao, M.A. (2017). Improving yield and quality of 'Merlot' with application of a mixture of plant hormones. Acta Hortic. 1157, 367-372
bioregulator, 'Merlot', physicochemical characteristics