Wine Arcana

Concept

Massal and clonal selection

Also known as Massal selection, Clonal selection

Massal and clonal selection are ways of choosing grapevines for vegetative propagation. Massal selection takes material from a group of selected vines; clonal selection follows the descendants of an individual source vine. Both preserve a variety through cuttings or grafting, while giving growers different ways to retain and evaluate variation within it.

A variety can contain different plant material

Grapevines grown from seed acquire a new combination of their parents' genes. Cuttings instead preserve the source vine's identity. Over repeated growth and propagation, mutations can create differences among plants of the same variety. Pinot Noir provides a familiar example of such variation, including differences in bunch form and productivity.

A clone can be selected for useful traits such as crop, ripening, or bunch structure. Performance still depends on rootstock, site, and season. Choosing a named clone is one planting decision alongside grafting, spacing, and training.

Selection and evaluation

Massal selection can preserve several lines from an established vineyard. Growers identify suitable source vines and propagate their material together. That makes old vineyards potential resources, particularly where they predate narrower planting programmes. Visible performance needs careful interpretation: a vine may crop differently because of its soil, health, or management rather than an inherited trait.

Clonal evaluation compares material under conditions intended to separate genetic differences from environmental ones. The OIV's procedure includes identity, health assessment, agronomic observations, and wine evaluation. Repeated observation is more informative than choosing a vine from a single season's fruit.

Polyclonal selection is a further approach. It assembles a group of evaluated lines to retain diversity within a variety. The OIV's protocol describes broad sampling followed by replicated field trials, helping distinguish genetic effects from differences in growing position. It is more formal than simply taking cuttings from several attractive vines.

Health and naming

Propagation can also transfer viruses. Leafroll illustrates why a productive-looking source vine needs health assessment. Selecting for a desirable crop trait and testing for pathogens address separate questions.

Foundation Plant Services at UC Davis makes another useful distinction. Its numbered selections record source material and testing, while FPS itself does not conduct a formal clonal performance evaluation for every accession. A selection number therefore identifies material; it does not rank wine quality or guarantee a particular vineyard result.

Identity testing has developed over time. The Australian Wine Research Institute now offers clonal identification using high-resolution DNA analysis and a verified reference database. Such a test can help establish what was planted, while field observation establishes how it performs in that vineyard.

For the drinker, a clonal or massal description gives information about planting material and the grower's priorities. Wine character follows the interaction of that material with farming, ripeness, and cellar choices.

Sources