Evaluation of the Performance and Adaptability of Wine Grape Varieties in Bhutanese Agroecological Conditions
Pema Yangdon, Thinley Wangdi, Mandira Acharja, Kinzang Wangmo, Kinzang Thinley, Thinley Gyeltshen, Choki Wangchuk, Pema Dechen and Kinley Gyeltshen
Abstract
Grapes (Vitis vinifera L.) are among the most important temperate fruit crops worldwide, widely used for winemaking, fresh consumption, and processed products such as raisins. In Bhutan, however, grape cultivation remains limited due to heavy monsoonal rainfall and insufficient research. While a few table grape varieties have previously been tested, the cultivation of wine grapes is entirely new. To explore their potential for a niche wine industry, 18 wine grape varieties were introduced in 2018 through a Public–Private Partnership between the Department of Agriculture and Bhutan Wine Company. This study evaluated nine of these varieties across three agroecological zones, Lingmethang (600 masl), Bajo (1200 masl), and Paro (2400 masl) from 2019 to 2024, using a Completely Randomized Design with two replications. Data on fruit and yield traits, including cluster number, cluster weight, cluster dimensions, total soluble solids (TSS), berry size, and yield per vine, were analysed using ANOVA and Tukey’s test in SPSS and R. The study found that all varieties contained TSS between 18% and 24%, the optimal range for winemaking, and yields between 2.9 and 4.9 kg per vine, highlighting their potential for commercial production. Significant genotype and location effects, along with strong genotype × environment interactions, were observed. Yield performance was site-specific, with Sauvignon Blanc and Pinot Noir performing best at Bajo, and Malbec and Cabernet cultivars excelling at Paro. Overall, all varieties produced superior yields and fruit quality at Paro, which is characterized by a warm climate with lower rainfall compared with the hot, wet conditions of Lingmethang. These findings confirm the feasibility of wine grape cultivation in Bhutan and highlight site-specific varietal suitability for commercial development. Consequently, all nine evaluated varieties were officially released for cultivation during the 27th Variety Release Committee meeting.