Privativa EU 38536, Pyrus communis L. 'Fox 9'

Origin Fox 9 is a clonal rootstock selected from open-pollinated seedlings of cv. Volpina (Pyrus communis L.), an old Emilia Romagna variety once used to breed seedling pear stocks. As selection E110 bred in 1988 at Bologna University’s Dipartimento di Colture Arboree (Bassi et al., 1993 and 1996), it has been under joint field testing since 1998 with Veneto regional authority’s Veneto Agricoltura extension, which carried out virus indexing, drafted propagation protocols, and ran nursery performance trials (as did Bari-based CO.VI.P.) and field testing in a commercial orchard established for the purpose with cvs. Abbé Fètel, Conference and Williams (Quartieri et al., 2007). Tree profile The tree is marked by a semi-upright growth habit and medium vigour; it has not exhibited signs of runners. The leaves are dark green, medium-sized and sub-round leaves with stipules. The leaf blade is slightly concave, the edge serrated and the apex comes to a point (Fig. 1). The branches feature a smooth, reddish-brown bark, small-sized, whitish lenticels, linear growth with irregular internodes separated by medium-sized nodes free of thorns (Fig. 1). The notably expansive root system provides good anchorage; plants multiplied via micro-propagation have plentiful root hairs (Fig. 1). Field performance It has good degree of hardiness, is tolerant of clay soils and is better suited to lime soils than quince (Fig. 2). t multiplies well by micro-propagation, although it needs further testing of its stool-bed aptitude. When grafted to the main pear cultivars, it exhibits optimum graft compatibility and well-formed scions. Observations in nursery indicate uniform response of plants, which displayed good vigour and a feathering aptitude similar to quince’s (Fig. 3). Effects on cultivars The Fox 9 pear stock is highly compatible with the most widely grown pear cultivars. It induces a higher vigour than quince BA29 in cvs. Abbé Fètel (+22%), Williams (+18%) and Conference (+38%) (Fig. 4). Spring shoot growth has been optimum in all the tested cultivars, as show by the data for winter pruning wood (Fig. 5). The yield data (Bassi et al., 1993; Quartieri et al., 2007) show that a response similar to quince BA29 for early bearing (7 kg/tree against 9 kg for BA29 at year three). By year five the yield of trees grafted to Fox 9 was consistently higher that that induced by BA29: respectively up 29 % and 40 % at leaf five and six as average of the three cultivars) (Fig. 6). Cumulative yield by year 6 (2004-2007) was on average higher than that with BA29 (+16 %, Fig. 6); yield efficiency was good, being similar to that for BA29 (Fig. 7). Fruits are of adequate (Figs. 8-10), have good flavour traits that are similar to those of fruits picked from trees on BA29 (Tab. 1) and hold maturity well on trees. Overall rating Pear seedling stock Fox 9 proved to be very promising for cvs. Abbé Fètel, Conference and Williams. It is easy to propagate, adapts well to the environment, and is advisable for use in soils of excessive active lime and high pH. It induces medium vigour and is thus suited to medium-density orchards (1800-2500 trees per hectare). The tree features a well-balanced shape, rapid initial bearing, especially when pruning in the first six years is limited to cuts designed to induce early bearing, and yield is optimum.