Influence of Plastic Roof on Fruit Quality and Yield of ‘Beauty Seedless’ Grape During Dry and Rainy Seasons

Abstract

A study on the influence of plastic roof applied from pruning to harvest, pruning to color change and flowering to color change on fruit quality, total nonstructural carbohydrate in shoot, yield, cost and returns of ‘Beauty Seedless’ grape was conducted in the Northern Thailand during dry and rainy seasons. The results showed that the vines growing under plastic roof from pruning to color change stage produced high cluster weight, number of clusters, yield and profit during both dry and rainy seasons. Moreover, the berry size and berry weight were increased and the percent of yield loss was decreased and no disease score was found during the dry season. The vines growing under plastic roof from pruning to harvest stage gave an increase in total anthocyanin content and tended to contain no disease score during the dry season. Similar trend was found in an increase in berry size, berry weight and total soluble solids and a decrease in disease score, titratable acidity and the percent of yield loss during the rainy season. No differences on the total non-structural carbohydrate content in shoot of the vines during both dry and rainy seasons were found among the treatments. The treatments applied plastic roof on vines gave higher profit than the control in both seasons. However, the control gave a marginal net profit in the dry season and a profit loss remained in the rainy season.