Morphological and quality variability of white wine grape (Vitis vinifera L.) varieties under Pune conditions

This study evaluated the ampelographical and bunch characteristics of 19 white wine grape varieties (Vitis vinifera L.) grafted on Dogridge rootstock at the National Active Germplasm Site, National Research Centre for Grapes, Pune, during 2023-24. The experiment was conducted on completely randomized block design comprising five vines per replication and three replications per cultivar. The results of the study revealed significant variability in the morphological characteristics of white wine grape varieties. The young shoot tip's opening with a high CV of 37.86 %, indicating substantial variation. The highest variability was observed for berry shape (CV 58.66 %) and berry color (CV 62.09 %), highlighted the diverse phenotypic traits among cultivars. Parameters such as bunch compactness and formation of seed showed lower variability, suggesting more consistency in these traits. Most cultivars had fully open young shoot tips. Tendril distribution was predominantly found sub-continuous, with unified tendrils. Young leaves were found mainly green colored with bronze spots (7). All cultivars exhibited bark peeling. The shoot attitude was primarily erect. Most mature leaves had large blades and pentagonal shapes. Berry density in bunches was generally compact, with round berries being the most common shape. Berry skin color was often green-yellow and all berries lacked anthocyanin coloration in the mesocarp. Time to bud burst ranged from 8.7 to 12.7 days after fruit pruning. Full bloom stage occurred between 34 and 44 days after fruit pruning. Flowering lasted 3.3 to 6.7 days. Veraison occurred from 95 to 114.67 days after fruit pruning and physiological berry maturity ranged from 122 to 147 days after fruit pruning. The results showed a range of correlations among various traits. Pruning biomass had a moderate positive correlation with 50 berry weight and berry skin thickness. Bunch weight showed strong correlations with bunch length and bunch width. TSS was negatively correlated with bunch weight and berry skin thickness. Total acids had a high positive correlation with malic acid. Ethanol content was positively correlated with TSS.