Perspectives for reducing seed shattering in ryegrasses

Ryegrasses (Lolium spp.) are widely cultivated due to their high productivity and excellent forage quality. So far, the breeding of ryegrasses has focused mainly on agronomic traits such as biomass yield, forage quality and disease resistance. However, for commercial success of a cultivar, a stable and high seed yield is a prerequisite. The harvestable seed yield can be lowered by several factors such as non-optimal pollination and fertilization, seed abortion and seed shattering. Seed shattering, i.e., the loss of seeds at ripening stage before or during harvest, was found to be the main factor reducing seed yield in ryegrass breeding germplasm of Agroscope. While in major cereal crops, such as rice, sorghum and barley seed shattering has been largely eliminated during domestication, that trait has been largely neglected in ryegrass breeding programs.

In order to pave the way for further breeding efforts, we summarized the knowledge of morphology on seed shattering in ryegrasses and used the advanced knowledge about seed shattering in major crops to identify putative candidate genes controlling seed shattering in ryegrasses.

Comparative genomic analyses revealed eleven candidate genes potentially controlling seed shattering in ryegrasses. These candidate genes showed homologies to genes known to be involved in the control of seed shattering in rice such as qSH1, SH5 or SHAT1 and provide interesting targets for functional validation in ryegrasses. Together with a reliable phenotyping method, these candidate genes provide promising tools for further development of efficient selection strategies for reduced seed shattering in ryegrasses.

This research received funding from Agroscope and Delley Seeds and Plants Ltd. It was a team effort of the Fodder Plant Breeding group at Agroscope and the Molecular Plant Breeding group at ETH Zurich.

Citation:
Kiesbauer J, Grieder C, Studer B and Kölliker R (2023) Perspectives for reducing seed shattering in ryegrasses. Grass and Forage Sci 12635.
external page https://doi.org/10.1111/gfs.12635