Breeding for resistance: conventional breeding for Plum pox virus resistant apricots (Prunus armeniaca L.) in Greece

Abstract

A large apricot breeding programme has been conducted at NAGREF‐Pomology Institute, Naoussa‐Greece, for the control of sharka disease, since 1989. Ten apricot cultivars of North American origin: ‘Stark Early Orange’, ‘Stella’, ‘NJA2’, ‘Sunglo’, ‘Veecot’, ‘Harlayne’, ‘Henderson’, ‘Goldrich’, ‘Orangered’ and ‘Early Blush’, selected for their resistance to the highly virulent local strain of Plum pox virus (PPV)‐M (Marcus), have been used as parents in crosses with quality cultivars, mainly with the local cv. Bebecou, from 1989 to 2003. Approximately 7000 hybrids have been created. Resistance to PPV was the main criterion of selection. Most hybrids have been subjected to artificial inoculation by PPV‐M and examined for symptom expression for more than five years. Indexing to GF‐305, as well as laboratory diagnostic tests, have been applied. The genetic analysis showed that: (1) 50% of the hybrids inherited resistance to PPV in the families where cvs. Stark Early Orange, NJA2, Sunglo, Veecot and Harlayne were used as a parent, and (2) 100% of the hybrids inherited resistance to PPV in the families where cv. Stella was one of the parents. Resistance to PPV appears to be under simple genetic control involving one gene locus. Promising apricot selections resistant to PPV‐M have been released.