The current status of breeding research in Lolium genus

Italian ryegrass ( Lolium multiflorum Lam.; IRG), an important Lolium species, is mainly cultivated in South Korea, Japan, China, and used as forage (pastes, hay, silage). Another important species of Lolium are perennial ryegrass ( Lolium perenne L.; PRG), which is cultivated in Europe, United States of America, Australia, and New Zealand. The main character of the genus Lolium , which includes IRG and PRG, is its palatability; however, Lolium species exhibit summer depression during hot summers. The breeding goal of Festulolium , an interspecific and generic hybridization product of Lolium and Festuca , is to overcome the shortcomings of Lolium species. As such, pasture breeding is same varieties because polycrossing methods are used as five or more genetic resources, but there are some differences within the individual varieties. Amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers are used to investigate the geographical origins, ploidy levels, biological status, donor information, and flowering seasons of these varieties. Genetic markers are also used to construct linkage maps. Based on linkage map analyses, studies of Lolium quantitative trait loci (QTL) contributed to the breeding of varieties with improved tolerance or resistance to biological and non-biological stress factors. In this study, we summarize recent studies on the cultivation status of IRG in South Korea, linkage mapping of Lolium , and associated QTL analyses. We also discuss interspecific and generic hybridization of Lolium and Festuca .