Almond Species Traditional Utilization

Considerable published information on almond species utilization focuses on their potential as valuable sources for genetic improvement through the breeding of cultivars and rootstocks. A number of useful traits have been identified, including earlier harvests, highly sealed soft-shelled nuts, later bloom for frost avoidance, and resistance to a range of diseases and pests, as well as environmental stresses such as drought, high temperatures, and salinity. The diverse genetic and geographic origins also increase the probability that evolutionarily independent and so potentially complementary mechanisms for resistance and/or tolerance can be recovered and utilized for crop improvement. In addition, since many resistance genes are monogenic and dominant, multiple resistances can be rapidly combined utilizing interspecies hybridization for rootstock development, with an added benefit being the increased invigoration of rootstock and scion growth often recovered in these interspecies hybrids. Wild species are also sometimes used directly as rootstocks due to their high levels of disease and stress resistance and regional adaptation.