Double cropping in Vitis vinifera L. cv. Pinot Noir: agronomical and physiological validation

Background and Aims: Environmental effects of global warming are leading to extended ripening seasons, which may either require or allow new vineyard management techniques. An innovative double-cropping technique is proposed for temperate climate areas. Methods and Results: The principle technique was to maintain the primary crop as well as to obtain a second, late ripening crop through release of dormancy of the auxiliary buds during the current season. Potted Pinot Noir vines were subjected to two forcing treatments over 2 years: trimming all the primary shoots at six nodes and removing any developing laterals at the end of the flowering and pea size stages. Vine growth, yield components and grape composition were monitored on both primary and forced shoots. In the second season, seasonal whole-vine gas exchange was evaluated in detail. Forced shoots carried 40–50% of the vine crop compared to primary shoots and fruit quality was greatly enhanced and higher TA was observed. Forcing treatments reached a similar net carbon dioxide exchange rate per vine compared to unforced Control about 2 weeks following auxiliary budburst. For the remainder of the season, forcing treatments maintained much higher net carbon dioxide exchange rate and water-use efficiency than unforced Control vines. Conclusions: Detailed agronomical and physiological evaluation for 2 years confirmed the reliability of the double-cropping technique without compromising the pruning point selection for the next cropping year. Significance of the Study: Future field application may disclose that this forcing technique is able to warrant two crops potentially suited to different wine styles within a single season.