Definition of zucchini

Cucurbita pepo has two cultivated subspecies, subsp. pepo and subsp. texana (Scheele) Filov, each of which encompasses four edible-fruited cultivar-groups (Paris, 2000b). These eight cultivar-groups are distinguished on the basis of fruit shape (Paris, 1986) (Fig. 1). Fruit shape is easily observed by all concerned with squash. Cucurbit fruit shape is largely determined early in ovary development (Périn et al., 2002) and does not change radically as the fruits develop (Figs 2 and ​and3).3). As a trait that is under polygenic control, fruit shape should to a large extent be reflective of genetic relationships, and this has been confirmed through analysis of DNA sequence polymorphisms (Katzir et al., 2000; Ferriol et al., 2003; Paris et al., 2003, 2015; Formisano et al., 2012; Gong et al., 2012).

Schematic representations of fruits from each of the eight edible-fruited cultivar-groups of Cucurbita pepo (Paris, 1986).

Young fruits of Cucurbita pepo, one from each edible-fruited cultivar-group. Left to right, top row, subsp. texana: Acorn, Straightneck, Crookneck, Scallop. Left to right, bottom row, subsp. pepo: Pumpkin, Vegetable Marrow, Cocozelle, Zucchini.

One mature fruit from each of the eight edible-fruited cultivar-groups of Cucurbita pepo. Top left: Pumpkin; bottom left: Vegetable Marrow; left to right: Cocozelle, Zucchini, Acorn; at right, top to bottom: Scallop, Crookneck, Straightneck.

The cultivar-group Zucchini is distinguished from all others of C. pepo by its fruit shape, which is uniformly cylindrical with a length to width ratio of 3·5–5·0 (Paris, 1986). The other seven cultivar-groups (fruit shapes) are Cocozelle (long bulbous cylindrical), Vegetable Marrow (short tapered cylindrical), Pumpkin (round), Scallop (flattened, with scalloped edges), Acorn (turbinate, with ridges and furrows), Crookneck (elongate, with a curved, narrow neck at the stem end) and Straightneck (elongate, with a constriction near the stem end) (Figs 1–3). The first four are classified within subsp. pepo and the last four within subsp. texana. Some pumpkins, as well as almost all zucchinis, cocozelles, vegetable marrows, scallops, crooknecks and straightnecks, are usually harvested for culinary use when young. Other pumpkins as well as the acorn squash are usually harvested when mature.