Vitis ×ruggerii

Ardenghi, Nicola M. G. & Cauzzi, Paolo, 2015, Alien grapes (Vitis, Vitaceae) in Sicily (Italy): novelties for the Sicilian and Mediterranean flora, Natural History Sciences 2 (2), pp. 137-148 : 141-142

Vitis ×ruggerii �rdenghi, Galasso, Banfi & Lastrucci,

Phytotaxa, 166 (3): 187. 2014.

(= V. berlandieri Planch. × V. rupestris Scheele )

Neophyte new to the flora of Sicily. Invasion status changed from naturalized to invasive for Italy and Europe.

Distribution. Widespread, especially in the southern part of the region; recorded from the provinces of Agrigento, Caltanissetta, Messina, Palermo, and Ragusa ( Fig. 1 ).

Habitat. Roadsides, olive groves, waste land, fences, walls, ditch embankments, often associated with ruderal perennial vegetation (Bromo-Oryzopsion miliaceae O.Bolòs 1970), occasionally with Phragmites australis (Cav.) Trin. ex Steud. stands and halo-nitrophilous chamaephyte communities (Salsolo oppositifoliae-Suaedion mollis Rigual 1972 ); 4-772 m.

Invasion status. Invasive. Similarly to V. rupestris , this nothospecies reproduces only vegetatively, being provided only with male flowers (see �rdenghi et al., 2015a); it commonly forms extended and dense monospecific stands, with covers reaching 100%, concealing spontaneous vegetation, edges of cultivations, roadsides, and buildings ( Fig. 4 ), particularly along the southern coast.

Use. Rootstocks of V. × ruggerii are at the base of modern Sicilian viticulture. Internationally renowned and economically valuable V. vinifera cultivars grown in Sicily for wine-making, such as ‘Calabrese’ (syn. ‘Nero d’Avola’), ‘Zibibbo’, ‘Ansonica’ (syn. ‘Inzolia’ or ‘Insolia’), ‘Catarratto Bianco comune’, and ‘Nerello Mascalese’, are grafted almost exclusively on this nothotaxon ( Bica, 2007; Ministero delle Politiche �gricole, �limentari e Forestali, 2015), which is additionally used as rootstock for table grape cultivars ( Regione Siciliana, 2014) ( Fig. 5 ). V. × ruggerii rootstocks began to be used in vineyards of southern Europe and North �frica after 1920, welcomed for their resistance to drought and limestone, high vigor, and grafting affinity with V. vinifera ( Galet, 1988) .

Notes. Two specimens collected in Acate and Calamonaci (collection numbers 04 and 33) belong to the cultivar ‘57 R’, characterized by 3- to slightly 5-lobed leaf blades. It can be easily distinguished from individuals of V. × koberi with lobed leaves (originating from cultivar ‘420 �’) for some typical V. rupestris features, such as the longitudinally folded leaf blades and their reniform shape, the largely U-shaped basal sinus, and the bright red color of petioles and nerves on the adaxial leaf surface ( Fig. 6 ). This rootstock, whose ability to produce fruits is controversial (see Galet, 1988, and Cosmo et al., 1958), has never been recorded before in the wild; due to incompatibility in grafting, its use has been almost abandoned ( Galet, 1988; Ministero delle Politiche �gricole, �limentari e Forestali, 2015).

V. × ruggerii , up to now recorded only from Spain, Italy, and France ( Laguna, 2004; �rdenghi et al., 2014; Tison & de Foucault, 2014), has recently been collected by the authors in Crete, where it can be considered naturalized; this is the first record for Greece. The plant was observed forming a thick, monospecific stand along an unsurfaced road (see specimina visa). As in Sicily, V. × ruggerii is the most employed rootstock in Greece ( Lazarakis, 2005).

Figures

Fig. 1 - Geographical distribution in Sicily of Vitis rupestris (red dots), Vitis ×goliath (green dots), and Vitis ×ruggerii (blue dots).

Fig. 4 - Invasive stand of Vitis ×ruggerii ‘775 P’ in �cate, with the first author posing for scale. The plant completely covers the fence of an olive grove and, on the extreme right, an almond tree (Photo: P. Cauzzi).

Fig. 5 - Rootstocks of Vitis ×ruggerii ‘140 Ru’ emerging from an abandoned vineyard in �cate (Photo: N.M.G.�rdenghi).

Fig. 6 - Vitis ×ruggerii: a) typical entire leaf blades; b-c) cultivar ‘57 R’ with lobed leaf blades (Photos: N. M. G. �rdenghi).