As part of a breeding programme begun in 1990 to develop dwarfing stocks for Vitis vinifera, commercial rootstocks under self- or open-pollination led to 400 seedlings, subsequently tested via cuttings for rooting ability and graft compatibility with the Cabernet Sauvignon, Chardonnay, Sangiovese wine grapes and the Amburg Muscat table grape. In the next step, the Sangiovese- grafted cuttings that performed best were tested for vigour and resistance to a high concentration of active limestone in comparison with eight commercial stocks. The 26 best-performing grafted accessions, together with the eight commercial stocks grafted with Sangiovese, were placed in a field to test the long-term induced effects on the scion. This trial resulted in the selection of two stocks bred by self-fertilisation with Binova, a hermaphrodite flower-bud mutation of SO4. The two new stocks were given the commercial names of STAR 50 and STAR 74. Both are marked by good vigour control, good lime tolerance and proved capable of controlling the vine’s excessive cropping and growth, while improving grape composition. STAR 50 and STAR 74 have recently been added to Italy’s National Grapevine Registry and are currently in pre-multiplication.
(Cesare Intrieri: Dipartimento di Scienze Agrarie- Settore Viticoltura - Università di Bologna- Viale Fanin 46, 40127, Bologna, Italy. Tel. 051.2096429, firstname.lastname@example.org)