“…For example, the genetic variation among elite orange, lemon, lime, and grapefruit cultivars is extremely narrow (Moore, 2001). Even though outcrossing is the norm in many perennials, many commercial cultivars have a restricted genetic base, for example, in cacao (Schnell et al, 2007) and oil palm (Cochard et al, 2009; Wening et al, 2012). In olives, there appears to be a fair amount of genetic diversity present in cultivated germplasm (Sensi et al, 2003), but this variability is dwindling rapidly as growers adopt modern growing practices and plant monocultures of a small number of cultivars (Haouane et al, 2011).…”