n the last decades, the progress in ryegrass (Loliumspp.) breeding was mainly onagronomic traits such as biomass yield, forage quality or disease resistance. However,for commercial success, a stable and high seed yield is a prerequisite for any cultivar.The realized seed yield is influenced by many different factors such as non-optimalpollination and fertilization, seed abortion and seed shattering. While seed shatteringhas been largely eliminated in major cereal crops such as rice, barley or sorghum dur-ing domestication, the trait has been largely neglected in ryegrass breeding programs.The close syntenic relationship of cereal and ryegrass genomes offers the opportu-nity to develop breeding approaches for reducing seed shattering in the latter bytransferring knowledge from the former. The objectives of this review are to (1) givean overview on the knowledge of morphology on seed shattering in cereal crops andryegrasses, (2) compare the genetic background underlying seed shattering in differ-ent species, (3) identify putative candidate genes controlling seed shattering in rye-grasses through comparative genomic analysis and (4) give an outlook on newbreeding strategies resulting in low seed shattering cultivars of ryegrasses and relatedforage grass species.