333 EM

History of Origin and Economic Significance

The grape rootstock 333 Ecole de Montpellier is a well-known Franco-American hybrid obtained in France in 1883 by the viticulturist Gustave Foëx. The variety was bred through the artificial interspecific crossing of the European cultural variety Cabernet-Sauvignon (Vitis vinifera) with the American wild species Vitis berlandieri. The rootstock variety 333 Ecole de Montpellier has found its main commercial application in France, where the estimated area of registered mother plantations and grafted vineyards is about 4,000 hectares. The main regions of cultivation and utilization of this rootstock are Champagne and Charentes.

The main advantage of the grape rootstock 333 Ecole de Montpellier is its exceptionally good adaptation to limestone soils and outstanding resistance to calcareous chlorosis. According to agrobiological research data, the variety tolerates up to 60% of total lime content in the soil and up to 40% of active lime, demonstrating an estimated chlorosis resistance index (CPI) of 70. Due to the deep placement of its root system, the rootstock variety 333 Ecole de Montpellier is well adapted to cultivation on shallow, dry soils and shows high resistance to drought. The plants also possess a valuable biological capacity to tolerate temporary water excess (waterlogging) in the soil during the spring vegetation period. On the other hand, the variety has a pronounced sensitivity to soil salinity caused by chlorides.

The interaction of the rootstock with scion components is characterized by specific features. At the initial stage after planting in the vineyard, young vines using the grape rootstock 333 Ecole de Montpellier develop rather slowly. However, subsequently, the rootstock imparts high growth vigor to the grafted European varieties and ensures high yields. In certain unfavorable years, excessive vegetative power of the cane can promote the coulure phenomenon (flower and ovary shedding). Under conditions of limited soil fertility or other limiting environmental factors, the varieties grafted onto the 333 Ecole de Montpellier rootstock produce high-quality viticultural and winemaking products.

Morphological Description of the Rootstock Variety 333 EM

Identification and approbation of the rootstock plantations are carried out based on a complex of the following leading botanical traits of the plant organs:

• Young shoot (tip): the apex of the growing shoot is open and characterized by a intense piping anthocyanin (wine-red) coloration along the edges of the lobes. The surface of the tip is covered with a high density of prostrate cobwebby hairs of a grayish-white color. The developing young leaves have a distinct reddish coloration.
• Mature leaf: has a circular shape; the leaf blade is entire or features five distinct lobes. The surface of the leaf blade is glabrous and shiny, with a specific blistered structure. The edges of the leaf lobes are characteristically involute (rolled inwards) and slightly twisted along the periphery.
• Petiole sinus and veining: the petiole sinus is slightly open, brace-shaped, or has lobes with slightly overlapping edges. The main leaf veins are characterized by the absence of erect and prostrate hairs, while the zone of the naked vein surface at the point of petiole attachment is often limited.
• Annual and mature shoot: the unlignified green shoot is characterized by a very ribbed surface and a circular or slightly elliptical cross-section; erect and prostrate hairs in the shoot pubescence are completely absent. The mature woody shoot retains a distinctly ribbed texture of the bark.
• Reproductive organs: the 333 Ecole de Montpellier variety has flowers of a functionally male type; it does not form developed bunches or berries.

Features of Agricultural Practices in Nursery Production

The technological indicators of cane production on mother plantations of the 333 Ecole de Montpellier variety are assessed as relatively low. The average productivity of mother vine areas in terms of standard rootstock material yield is only 10,000 to 30,000 meters of cane per hectare. To achieve complete lignification and proper wood ripening of the annual growth along its entire length, the variety requires exceptionally favorable temperature conditions in the autumn vegetation period.

In nursery conditions, the grape rootstock 333 Ecole de Montpellier demonstrates a moderate cutting capacity in combination with a good grafting aptitude and high-quality union formation in bench grafting with standard Vitis vinifera varieties. When conducting winter grafting and material sorting, it should be taken into account that mother vines are prone to forming a large cane diameter. Increased thickness of the rootstock cuttings may cause technological inconveniences during the selection of scion-rootstock pairs and the performance of mechanized cutting operations.

Within the framework of the official system of clonal selection in France, four elite clones of the 333 Ecole de Montpellier rootstock have been isolated and certified, receiving official state registration numbers 260, 263, 1049, and 1105. The commercial clone under number 263 holds the greatest production significance. As of 2017, the mother plantations of this clone occupied an area of 20 hectares and 53 ares, providing nursery farms with high-quality certified rootstock material.