Vitis × bacoi Ardenghi, Galasso & Banfi

Ardenghi, Nicola M. G., Banfi, Enrico & Galasso, Gabriele, 2015, A taxonomic survey of the genus Vitis L. (Vitaceae) in Italy, part II: the ‘ Euro-American’ hybrids, Phytotaxa 224 (3), pp. 232-246 : 235-240

Vitis × bacoi Ardenghi, Galasso & Banfi , hybr. nov. Figs. 1 , 2A, 2C, 2E, 2G , 3A , 4

( V. riparia Michaux × V. vinifera Linnaeus )

Planta hybrida , a V. riparia foliorum laminis ab ultimo vere rubescentibus, initialibus quinque vel septem lobatis, pubescentia araneosa in nervos et seminibus longioribus differt ; a V. vinifera bacis sapore asperrimo, pilorum fasciculis semper in superficiem abaxialem foliorum ad nervorum axillas positis differt ; a V. × goliath foliorum basi lyrata usque ad formam U differt .

Type: — ITALY. Lombardy: Santo Stefano Ticino (Milano), Cascina Fontana, lato N della ferrovia (WGS84: 45.479962°N 8.918647°E), 145 m, no exp., robinieto su sponda di fossato alla base della massicciata ferroviaria, con Robinia pseudoacacia , Rubus sect. Corylifolii , Parthenocissus quinquefolia , 13 September 2014, N. Ardenghi s.n. (holotype MSNM!, 6 sheets, isotype FI!, 4 sheets). [ Fig. 4 ; images of parts A− F are available at http://www.comune.milano.it/dseserver/webcity/documenti.nsf/0/ 49839462f80662afc12571010055c8c5?OpenDocument (accessed: 5 September 2015)].

= ‘ Vitis × andrasovszkyana Terpó’ (1988: 37), nom. inval. (see “Notes”)

Type:—originally not indicated.

Deciduous woody vine, climbing or creeping-prostrate, hermaphrodite. Tendrils bifurcate, a tendril or inflorescence present at only 2 consecutive nodes. Leaf blades thin, up to 25 cm long, not conduplicate, cordate, from 5(–7)-palmatelobed, with deep round sinuses (especially in the oldest leaves), to slightly 3-lobed or subentire, usually with phylloxera galls. Adaxial surface dark green, in late-season leaves usually with large purplish-red to purple blotches (anthocyanic pigmentation) extending from the margins towards the centre of the blade (this feature, persisting in dried specimens, is due not only to normal leaf senescence, but also to nutrient deficiency, injuries, virus and fungal infections, see Eynard & Dalmasso 1990, and Keller 2015), dull, tomentose in immature leaves, glabrous or with sparse arachnoid pubescence in mature ones, veins whitish to greenish-white, with arachnoid and hirtellous pubescence; abaxial surface tomentose in immature leaves, sparsely hirtellous to subglabrous in mature ones, with hirtellous and whitish arachnoid pubescence on the veins at the petiole insertion; veins surface hirtellous and arachnoid pubescent, with dense whitish tufts of rigid hairs at their axils. Margins hirtellous, with sparse to dense arachnoid pubescence, sharply dentate, teeth acute (usually acute triangle-shaped), narrow, rarely obtuse (broadly triangular or pointed-arch shaped); teeth at the ends of the central and the two main lateral veins usually prominent, acuminate. Leaf base U-shaped to lyre-shaped, in the latter case with the ends sometimes overlapping. Petiole glabrous to glabrescent, with sparse arachnoid pubescence, usually yellowish-green. Flowers hermaphrodite. Infructescences up to 10.5 cm long and 3.5 cm wide or more, cylindrical in outline, usually compact (berries touching each other); peduncle about 8 cm long; rachis glabrescent, with sparse arachnoid pubescence; pedicels 6−8 mm long. Berries up to 60 or more per cluster, 8−10 mm in diameter, spherical, black with a thin layer of pruine; exocarp (“skin”) adherent to the mesocarp; mesocarp (“flesh”) yellowishred. Flavor sharp and astringent. Seeds 1−2 per berry, 5.5−5.8 mm long, 3.8-4.1 mm wide (including beak); body spheroidal to ellipsoidal-obovoid, apex roundish, brown; beak 1.0− 1.5 mm long, 1.3−1.8 mm wide (at seed base), usually obtrapezoidal in outline, brownish; chalaza 1.3−1.9 mm long, 0.8−0.9 mm wide, ovate.

Etymology: —Dedicated to François Baco (1865−1947), French agronomist, famous for selecting in 1902 the direct-producer hybrid ‘Baco 1’, also known as ‘Baco noir’ and ‘24–23 Baco’ ( Galet 1988), employed for the production of the red wine ‘Baco’ or ‘Bacò’ (whose name is not related to the Greek god Bacchus, as wrongly stated by some sources), very popular in different parts of Europe until the late 20 th century.

Ecology: —Moist and deep to drained and light soils; moderately calciphile, heliophilous.

Area of origin and distribution in Europe: —Artificial hybrid originating in France ( Galet 1988), although spontaneous hybridization between the two parental species may occur in nature ( Terpó 1988, Laguna 2005, Bodor et al. 2011). In Europe, it is known as a casual or naturalized alien in Spain ( Laguna 2005) and Hungary ( Terpó 1988, Bodor et al. 2011).

Distribution in Italy and habitat: — Lombardy, Friuli Venezia Giulia, and Tuscany (this paper). Mesic woodlands often dominated by Robinia pseudoacacia Linnaeus (1753: 722) , wasteland.

Degree of naturalization: —Naturalized.

Use: —Hybrids between V. riparia and V. vinifera belong to a series of hybridogenic cultivars obtained between the 1880’s and the early 1900’s (especially in France) to face phylloxera and some major fungal diseases affecting viticulture. They followed the earliest generation of hybrids originating from the crossing of V. labrusca with V. vinifera and/or other American species, including V. riparia (see Galet 1988, Eynard & Dalmasso 1990, Ardenghi et al. 2015). Hybrids between V. riparia and V. vinifera were originally employed as rootstock (e.g., ‘142 E.M.’, ‘143 Mgt’, and ‘26 Geisenheim’), but soon discarded for unsatisfactory root system-resistance to phylloxera (trait inherited from V. vinifera ) and susceptibility to limestone (character acquired from V. riparia ) ( Galet 1988). However, thanks to their hardiness, easy reproduction from cuttings, early ripening, and low sensibility both to powdery and downy mildew, they had an increasing success as direct-producers, allowing wine production mainly in areas traditionally unsuitable for viticulture, such as mountain and nordic regions ( Galet 1988), in a similar way to V. labrusca × V. riparia (Ardenghi et al. 2015) . The most successful cultivar proved to be ‘Baco 1’ (or ‘Baco noir’), selected in 1902 by the French agronomist François Baco, who crossed V. vinifera ‘Folle blanche’ with V. riparia . The resulting product was ‘Baco’ (known also as ‘Bacò’ and ‘Baco noir’), a very alcoholic red wine, deeply colored, with a characteristic riparia -like bitter and herbaceous flavor, which soon became popular in France and Italy, well-appreciated by both viticulturists and subsistence farmers. ‘Baco 1’ vineyards reached a cover of 11,000 ha in France ( Galet 1988), and about 800 ha in Italy (Istituto centrale di statistica & Ministero dell’agricoltura e delle foreste 1972), despite legislative obstacles to the direct-producers plantation since the early 1930’s (see Ardenghi et al. 2015). However, a major decreasing of ‘Baco 1’ vineyards occurred from the 1950’s, which evolved into a complete abandonment of the cultivation during the second half of the century: although the plantation of riparia - vinifera hybrids is implicitly allowed by Council Regulation (EC) No. 479/2008 [Article 24, paragraph 1(a)], currently ‘Baco 1’ does not appear in the national wine grape cultivar catalogues of France and Italy ( Galet 1988, Robinson et al. 2012, FranceAgriMer 2015, Ministero delle Politiche Agricole, Alimentari e Forestali 2015), thus preventing its cultivation for the purpose of commercial wine production. The hybrid is still commercially planted on a small scale in Switzerland and its employment as a wine grape is increasing in the United States and Canada ( Robinson et al. 2012, Ufficio federale dell’agricoltura UFAG 2014+).

Notes: — Terpó (1988) proposed the name ‘ Vitis × andrasovszkyana ’ for the hybrid between V. riparia [sub ‘ V. vulpina Linnaeus (1753: 203) subsp. riparia (Michaux) Terpó’ (1988: 34)] and V. vinifera . However, in accordance with Art. 30.8 of the ICN ( McNeill et al. 2012), this name is invalid, having been published within a doctoral thesis not including an explicit statement or other internal evidence that it is regarded as an effective publication by the author. Additionally, neither an International Standard Book Number (ISBN) nor the name of the printer, publisher, or distributor is provided (see Art. 30 Note 4). Two further elements make Terpó’s name invalid: no type specimen is indicated (see Art. 40.1) and the name is not accompanied by a Latin description or diagnosis or by a reference to a previously and effectively published Latin description or diagnosis, but only by a Czech description (see Arts. 32.4, 39.1, and H.10.1). Moreover the rank is inappropriate for the proposed hybrid formula (Art. H.5).

The same problems regarding the name ‘ V. × andrasovszkyana ’ apply to the other nothotaxa described by Terpó in his doctoral thesis, namely: ‘ V. × rathayana Terpó var. rathayana ’ [1988: 35(−36)] and ‘var. karpatiana Terpó’ (1988: 36; ‘kárpatiána’) [= V. sylvestris Gmelin (1805: 543) × V. vulpina ], ‘ V. × kozmae Terpó var. kozmae ’ [1988: 36(−37)], and ‘var. zemplenica Terpó’ (1988: 37) (= V. sylvestris × V. vinifera ).

Since Terpó’s doctoral thesis is not acceptable as a publication, the new combinations there proposed are not valid. Among them, ‘ V. vulpina subsp. riparia (Michaux) Terpó’ (1988: 34) is additionally a later isonym (Art. 6 Note 2), having already been published by Clausen (1949: 9).

Unisexual individuals belonging to this nothotaxon may occur in the wild: a number of V. × bacoi cultivars, in fact, bear unisexual flowers, such as ‘143 Mgt’ (male), ‘142 E.M.’, and ‘26 Geisenheim’ (female) ( Galet 1988).

Figures

FIGURE 1. Vitis ×bacoi. Leaf blade variability: a, c, e) adaxial surface; b, d, f) abaxial surface.

FIGURE 2. A–B) Petiole insertion (abaxial surface). C–D) Petiole insertion detail. E–F) Vein axils (abaxial leaf surface). G–H) Abaxial leaf surface pubescence. A, C, E, G) V.×bacoi; B, D, F, H) V.×goliath. All photos by Michele Zilioli.

FIGURE 3. Seeds, ventral (on the left) and dorsal (on the right) sides. A) V.×bacoi; B) V.×goliath; C) V. vinifera; D) V. riparia; E) V. ×instabilis. All photos by Michele Zilioli.

FIGURE 4. Holotype of V.×bacoi Ardenghi, Galasso & Banfi, parts A, C, D, F (MSNM).