Almond

Abstract

The almond is economically the most important tree nut in the world. Its production is limited to areas characterized by a Mediterranean climate, including regions in the Mediterranean countries, the Central Valley of California, the Middle East, Central Asia, the Himalayan slopes, and the Southern Hemisphere, including Chile, Argentina, South Africa, and Australia. The main production region in the world is the Central Valley of California. The cultivation of almond in the eastern Mediterranean area occurred as early as the second millennium BC. Selection for domesticated almond types favored sweet kernels and larger nut size among these wild populations. Traditional seed propagation resulted in extensive genetic variability due, in part, to the obligate out-crossing nature of the self-incompatible almond. Local cultivars and landraces were selected over centuries of almond growing and in the twentieth century breeding activities began. Currently, there is active almond breeding programs in Spain, France, the USA and Israel. Self-compatibility has become the main objective along with late blooming, frost tolerance, resistance to diseases, and tree architecture. Despite the difficulties in defining a kernel quality ideotype due to the differences in consumer preferences, almond quality is currently an important breeding goal.