Double cropping inVitis viniferaL. cv. Pinot Noir: agronomical and physiological validation

Abstract

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.

Evaluation of carbon balance and carbohydrate reserves from forced (Vitis vinifera L.) cv. Tempranillo vines

“…Because leaf net photosynthesis is an input to the whole canopy net carbon exchange model, the decline in leaf net photosynthesis observed in CF early , which we attributed to the extremely high LA/fruit ratio, was also observed by the whole-canopy model ( Figure 4C ). In a forced double cropping experiment, NCE/LA was reported to be higher in forced vines than in unforced vines due to the younger canopy ( Poni et al., 2021 ). However, these vines had a LA/fruit ratio of 2 m 2 /kg because primary crop was not removed at forcing, which is close to the LA/fruit ratio we observed in CF late but significantly lower than that observed in CF early ( Table 2 ).…”

“…This technique, double cropping, is a version of forced regrowth in which the primary crop and the leaves of the six basal nodes are retained at the time of forcing. It was validated in Pinot Noir in two consecutive years, ( Poni et al., 2021 ) and in Tempranillo in only one season ( Martínez De Toda, 2021 ) demonstrating that dormant buds are capable to break dormancy without removing all the leaves. Double cropping overcame the yield reduction observed with the crop forcing technique ( Lavado et al., 2019 ; Martinez De Toda et al., 2019 ; Martínez-Moreno et al., 2019 ; Pou et al., 2019 ), as the sum of primary and forced yields was even higher than in the non-forced vines ( Martínez De Toda, 2021 ; Poni et al., 2021 ).…”

“…It was validated in Pinot Noir in two consecutive years, ( Poni et al., 2021 ) and in Tempranillo in only one season ( Martínez De Toda, 2021 ) demonstrating that dormant buds are capable to break dormancy without removing all the leaves. Double cropping overcame the yield reduction observed with the crop forcing technique ( Lavado et al., 2019 ; Martinez De Toda et al., 2019 ; Martínez-Moreno et al., 2019 ; Pou et al., 2019 ), as the sum of primary and forced yields was even higher than in the non-forced vines ( Martínez De Toda, 2021 ; Poni et al., 2021 ). Moreover, the carbon balance of the vine was even improved in forced vines as the leaf area was substantially restored with younger leaves, which ended up in a more functional canopy than the canopy of the unforced vines ( Poni et al., 2021 ).…”

“…Double cropping overcame the yield reduction observed with the crop forcing technique ( Lavado et al., 2019 ; Martinez De Toda et al., 2019 ; Martínez-Moreno et al., 2019 ; Pou et al., 2019 ), as the sum of primary and forced yields was even higher than in the non-forced vines ( Martínez De Toda, 2021 ; Poni et al., 2021 ). Moreover, the carbon balance of the vine was even improved in forced vines as the leaf area was substantially restored with younger leaves, which ended up in a more functional canopy than the canopy of the unforced vines ( Poni et al., 2021 ). In addition, unlike our experiment in which NCE m was reduced to zero for about two weeks after forcing ( Figure 4C ), in Poni et al.…”

“…Therefore, the two main limitations of the crop forcing technique are i) an incomplete inflorescence primordia formation before dormant bud unlocking and ii) the low carbohydrates availability caused by removing all leaves which can lead to a source limitation affecting yield for the current and the next year ( Poni et al., 2020 ). An alternative crop forcing technique (named double cropping) in which neither the primary crop nor the leaves bellow the trimming point (node six) were removed, was validated on potted Pinot Noir vines by Poni et al. (2021) .…”