New selections of Prunus persica for low chill Mediterranean climate areas

Abstract

In the late 1990s, CREA and the University of Palermo initiated a peach-breeding program in order to select new genotypes suitable for the fruit growing areas of southern Italy. These regions are generally characterized by short, mild winters and long, hot, dry summers. International cultivars grown in continental environments often have problems related to climatic limitations, such as the failure to satisfy the winter chill requirements. About 40 different peach and nectarine cultivars with different fruit characteristics (size, skin over colour, flesh firmness, sugar content, titratable acidity, absence of split-pit) were used as parents in a breeding program by CREA. The best selections were propagated through grafting onto peach × almond GF 677 rootstock and then tested in different sites, including one experimental orchard located in the southern coastline of Sicily (latitude 37°30'N). Over the past 15 years, the aim was to identify the "hardiest and best" selections, on the basis of the main agronomic characteristics (such as disease susceptibility and productivity) and quality of fruits (resistance to split-pit). This article reports the main qualitative characteristics (such as red over colour, fruit weight, soluble solids content, soluble solids/titratable acidity ratio) of 13 yellow peaches, 1 white peach and 3 yellow nectarines selected to date in Sicily. Data were collected over at least 5 years and compared with some international cultivars in the same experimental orchard. The ripening period of the different selections runs from the second week of June until the first week of September. Some selections show innovative characteristics, with excellent fruit quality and well-adapted, hardy trees. For the climatic conditions in which they were assessed, it is believed that the selected genotypes can perform well in areas with at least 600-700 chilling units (eventually even lower).