Spring Onion (Allium fistulosum L.) Breeding Strategies

Abstract

Spring onion (Allium fistulosum L.) belongs to subgenus Cepa, genus Allium and family Liliaceae and popularly known as scallion, Welsh onion and Japanese bunching onion. Cultivation of spring onion dates back to 200 BC in China and reached Japan before 500 AD which later spread to Southeast Asia. Spring onion is grown worldwide, however the main area of cultivation remains in East Asia from Siberia to tropical Asia including China, Taiwan, Japan, the Philippines, Malaysia and Indonesia. The plant is a perennial herb, does not produce bulbs, and possesses hollow leaves and has traditionally been used in Chinese folk medicine to treat common cold, influenza, abdominal pain, headache and cardiovascular disease as well as having antifungal and antibacterial effects. Spring onion is known for its flavor and aroma and is a rich source of vitamin C, A and B6, thiamine, folate, rhamnose, galactose, glucose, arabinose and xylose. Production of F1 hybrids is considered as one of the main goals in crop breeding. The length of time taken is the main restriction in breeding programs as eight or more generations of inbreeding are needed to establish homozygous lines that can be applied in hybrid production. This process can be enhanced by using doubled haploid (DH) lines as components of hybrid cultivars. In this chapter, we give an overview of the origin, botanical classification, distribution, reported health benefits, genetic resource and conservation, crop cultivation practices and recent advances on biotechnology, and molecular biology and their application for crop improvement in connection with traditional breeding methods of spring onion. In this aspect, mutational breeding and somatic hybridization are the potential approaches for the development of new high-yielding and disease-resistant cultivars.