FIELD RESPONSE OF VITIS-VINIFERA CULTIVARS TO METHANOL

The response of Vitis vinifera cultivars to methanol was investigated at the Orchard Mesa Research Center in Grand Junction, Colorado. Suble thal methanol doses, based on visual observations, were 90% for leaves and 100% for trunks. The accumulation of total soluble solids (TSS) i n berries was also monitored weekly until harvest. There was no signif icant difference between the treated and control vines;during the peri od of study, with the exception of Muscat blanc, which showed a slight ly higher TSS content in methanol-sprayed vines than in controls. This difference, however, disappeared during ripening. There was no signif icant effect of methanol on photosynthesis, transpiration, nor stomata l resistance. At harvest, data on yields estimated by cluster weight, berry weight and berry size indicated no differences between the two t reatments. Methanol did not alter cold hardiness of dormant buds, meas ured by differential thermal analysis. It was concluded that in this s tudy methanol had little or no physiological, nor practical effect on grapes.