Perspectives for reducing seed shattering in ryegrasses

Abstract

In the last decades, the progress in ryegrass (Lolium spp.) breeding was mainly on agronomic 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-optimal pollination and fertilization, seed abortion and seed shattering. While seed shattering has been largely eliminated in major cereal crops such as rice, barley or sorghum during domestication, the trait has been largely neglected in ryegrass breeding programs. The close syntenic relationship of cereal and ryegrass genomes offers the opportunity to develop breeding approaches for reducing seed shattering in the latter by transferring knowledge from the former. The objectives of this review are to (1) give an overview on the knowledge of morphology on seed shattering in cereal crops and ryegrasses, (2) compare the genetic background underlying seed shattering in different species, (3) identify putative candidate genes controlling seed shattering in ryegrasses through comparative genomic analysis and (4) give an outlook on new breeding strategies resulting in low seed shattering cultivars of ryegrasses and related forage grass species.