Double Cropping in Vitis vinifera L. Pinot Noir: Myth or Reality?

Abstract

A novel bud-forcing technique aimed at obtaining two crops (primary and forced) within the same season was tested on potted Pinot noir grapevines. Removing young, vegetative organs from primary shoots trimmed to six nodes in early summer allows dormant buds to break para-dormancy, leading to a delayed, second crop. Meanwhile, the primary crop is left untouched. In our study, bud-forcing was applied at three different timings (full flowering, fruit-set, groat-sized berries) and compared with an unforced control (UC). Vegetative growth, yield components, shoot and vine balance as leaf area-to-yield ratios, leaf gas exchange, and grape composition were determined. Regardless of the timing of application, forcing was effective at unlocking either apical or sub-apical dormant buds on the trimmed shoot, whereas the more basal nodes stayed dormant. The additional crop present on forced shoots was 40%–50% of primary crop, which equated to approximately 1 kg/vine for all treatments. Fruitfulness on newly formed forced shoots varied from 0.8 to 1.1 clusters/shoot. Primary clusters in vines subjected to forced treatments reached target maturity with a delay of 7–12 days compared to UC, whereas forced-crop, picked at the latest available date (October 7) showed higher total soluble solids, anthocyanins and phenolics than the primary crop while retaining higher acidity. This ripening behavior was reflected in the higher A rates measured in late season on the basal leaves of forced shoots versus those of primary shoots. Forcing did not compromise fruitfulness of the basal primary nodes, which set at about 1.2 inflorescence primordia/shoot. This is the first report supporting the feasibility of double cropping in Vitis vinifera L. in warm viticulture regions.

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“…Recently it has been reported an original variant of this technique that is able to obtain fruit with different levels of maturity on a same grapevine (Poni et al, 2020). The results of this study show that primary clusters in grapevines subjected to forced treatments reached target maturity with a delay of 7 to 12 days compared to unforced control, whereas forced-crop, picked at the latest available date showed higher total soluble solids, anthocyanins and phenolics than the primary crop while retaining higher acidity.…”

“…2020). The authors of this study suggested that forcing applied in fruit-set was preferable to the ones performed in full flowering and in groat-sized berries stages in terms of milder the basal primary nodes, which set at about 1.2 inflorescence primordia/shoot (Poni et al, 2020). The authors of this study suggested that forcing applied in fruit-set was preferable the basal primary nodes, which set at about 1.2 inflorescence primordia/shoot (Poni et al, 2020).…”

“…The results of this study show that primary clusters in grapevines subjected to forced treatments reached target maturity with a delay of 7 to 12 days compared to unforced control, whereas forced-crop, picked at the latest available date showed higher total soluble solids, anthocyanins and phenolics than the primary crop while retaining higher acidity. In this way, forcing regrowth treatments allowed to delay ripening of both crops improving fruit quality at harvest (Poni et al, 2020). These results can be explained because basal leaves belonging to forcing shoots reached higher assimilation rates than the ones from primary shoots and this type of forcing did not compromise fruitfulness of the basal primary nodes, which set at about 1.2 inflorescence primordia/shoot (Poni et al, 2020).…”

“…In this way, forcing regrowth treatments allowed to delay ripening of both crops improving fruit quality at harvest (Poni et al, 2020). These results can be explained because basal leaves belonging to forcing shoots reached higher assimilation rates than the ones from primary shoots and this type of forcing did not compromise fruitfulness of the basal primary nodes, which set at about 1.2 inflorescence primordia/shoot (Poni et al, 2020). The authors of this study suggested that forcing applied in fruit-set was preferable to the ones performed in full flowering and in groat-sized berries stages in terms of milder ripening delay and by a balanced leaf to fruit ratio.…”

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

“…These ratios are close to the optimal value sought of 100%, meaning that one forced shoot develops from the apical or subapical node of each trimmed cane and then the subtending nodes stay dormant to allow standard winter pruning. In a preliminary proof of concept paper on the technique, Poni et al (2020) have shown that the response of each single trimmed shoot to the forcing treatment depends upon its size, that is basal diameter. It is likely that the pot environment has constrained vine size, therefore limiting, although not to great extent, the number of developed forced shoots.…”