Asparagus (Asparagus officinalis L.) Breeding

Abstract

Garden asparagus (Asparagus officinalis L.) is an important horticultural plant worldwide. The proposed Center of Origin of this crop comprises Eastern Europe, Caucasus and Siberia. Asparagus officinalis is a monocotyledonous, perennial, diploid, dioecious species with a chromosome number of 2n = 2x = 20. This species belongs to the Asparagus genus which comprises dioecious (Asparagus subgenus) and hermaphroditic species (Myrsiphyllum and Protasparagus subgenera). Polyploidization seems to have played an important role in the evolution of this genus due to a wide range of ploidy levels (2x, 4x, 6x, 8x, 10x,12x), found in inter- and intraspecific taxa. Nowadays, the modern cultivars are diploid hybrids with a narrow genetic base due to their common origin, the Violet Dutch population. The genetic resources of asparagus are an excellent source of genes of interest in breeding programs by using different landraces and wild related species tolerant to biotic and abiotic stresses. These genetic resources may also contribute to develop new varieties with higher bioactive compounds that is an increasing consumer demand. In this chapter, we present an overview of the new advances on genealogy, cytogenetics, genetic resources characterization and conservation, biotechnology and molecular markers linked to sex. Garden asparagus male plants are economically more profitable than females and therefore breeders aim to develop all-male hybrids. Recently, the asparagus reference genome was released and the first saturated genetic map has been obtained. These tools can be used to locate genes and/or QTLs controlling agro-morphic traits and to carry out marker-assisted selection (MAS).