35 Il miglioramento genetico per la resistenza a sharka in pesco: risultati del progetto italiano PPVCON Alessandro Liverani 1* , A.R. Babini 2 , Daniele Bassi 3 , F. Brandi 1 , L.F. Ciarmiello 8 , Luigi Conte 4 , L. Ferretti 5 , S. Foschi 11 , Daniela Giovannini 1 , Edgardo Giordani 6 , S. Micali 4 , Valter Nencetti 6 , F. Palmisano 7 , G. Pasquini 5 , P. Piccirillo 8 , C. Poggi Pollini 9 , Roberta Quarta 4 , C. Ratti 9 , Alisea Sartori 4 , Vito Savino 10 , M. Terlizzi 4 , Ignazio Verde 4 1 CRA Unità di Ricerca per la Frutticoltura, Forlì 2 Servizio Fitosanitario Regione Emilia Romagna, Bologna 3 Dipartimento di Produzione Vegetale, Università di Milano 4 CRA- Centro di Ricerca per la Frutticoltura, Roma 5 CRA - Centro di Ricerca per la Patologia Vegetale, Roma 6 Dipartimento di Scienze delle Produzioni Vegetali, del Suolo e dell’Ambiente Agroforestale - Sezione di Coltivazioni Arboree - Università di Firenze 7 CNR - Istituto di Virologia Vegetale, Unità Operativa di Bari 8 CRA- Unità di Ricerca per la Frutticoltura, Caserta 9 Dipartimento di Scienze e Tecnologie Agroambientali, Università di Bologna 10 Dipartimento di Protezione delle Piante e Microbiologia Applicata, Università di Bari 11 CRPV, Cesena (FC) Ricezione ; Accettazione 11 febbraio 2011 Peach breeding for ppv resistance: results from the italian project PPV- CON Abstract. Sharka is a worldwide serious disease with a severe impact on the productivity and fruit qual- ity of Prunus species. It is caused by Plum Pox Virus (PPV), a virus against which no chemical or biological curative treatments are available. PPV is easily trans- mitted by aphids and by grafting; so, despite the con- siderable efforts made in many countries, PPV has spread in all the most important Prunus growing areas. The current short-term solution is the eradica- tion of infected trees and the plantation of virus-free material. In Italy, the virus presence was first identi- fied in 1973 on apricot trees in Val Venosta area (Northern Italy). Since then, and despite the precau- tionary measures put in place, it has been spreading in almost all Italian regions, posing a serious threat to the stone fruit industry. In Emilia Romagna region (southern Po valley) it has been found since the early ‘80s, but the situation has worsened over the past decade, when outbreaks of the M strain of the virus have been identified. The M strain is characterized by a fast spreading by aphid vectors. The Italian Ministry of Agriculture sponsored the National Project PPV- CON, aimed to fight the virus threat through breeding actions in order to increase tolerance or introduce resistance into peach and improve knowledge on the virus biology and host interaction as well. No source of resistance has yet been found in peach, thus the isolation and introgression into P. persica of genes coding for the resistance to Sharka disease would be of significant economic and environmental benefit. In France, the resistance was found in P. davidiana (clone P1908), a species related to peach. In the off- spring obtained from crossing ‘Summergrand’ (yellow- flesh nectarine) and P1908, six QTL (Quantitative Trait Loci) were identified. One of them, highly corre- lated to the resistance, appears to be homologous to a QTL found in apricot. High level of resistance was also observed in several almond cultivars and the potential role of this species as a source of resistance to PPV in peach breeding programs has been demon- strated (Gradziel, 2002; Martínez-Gómez et al., 2004). As an alternative or complementary approach, geneti- cally engineered resistance by transgenes obtained from the virus itself is being tested. Transgenic PPV resistant Prunus domestica plants containing the PPV-CP (coat protein) gene have been obtained . Field tests performed on ‘C5’ selection, one of these transgenic clones (now patented as ‘Honey Sweet’), clearly demonstrated to be resistant to PPV infection either through aphid vectors and by graft inoculation. Despite ethical-legislative limitations to the use of genetically modified organisms (GMO) in the European Union, at present, the goal of obtaining Review n. - Italus Hortus ( ), 2011: 35-44 * alessandro.liverani@entecra.it