Autotetraploid Breeding in Perennial Rye (Secale cereanum): Cytogenetic Challenges, Agronomic Potential, and Future Prospects

Abstract

Perennial rye (Secale cereanum), an interspecific hybrid derived from cultivated rye (Secale cereale L.) and perennial wild rye (Secale strictum), has potential for the development of more sustainable perennial cereal systems. However, its breeding and agronomic utilization are constrained by low fertility and irregular meiotic chromosome behaviour. Induced chromosome doubling has therefore been investigated as a potential approach to improving its reproductive stability and agronomic performance. Whole-genome duplication commonly produces a gigas effect characterized by increased organ size, vegetative vigour, biomass production, and, in some genotypes, enhanced tolerance to abiotic stress. Nevertheless, reproductive responses remain variable because multivalent formation and irregular chromosome segregation may reduce pollen viability, seed set, and grain yield. Evidence from established autopolyploid systems suggests that improved fertility may depend on selection for more regular bivalent pairing, favourable genetic backgrounds, and changes in the regulation of genes involved in meiotic chromosome recognition and synapsis. However, these mechanisms remain insufficiently investigated in perennial rye. Future progress will require the integration of cytogenetic screening, molecular analysis, long-term field evaluation, and high-throughput physiological phenotyping. Such an approach may facilitate the development of autotetraploid perennial rye germplasm combining persistence, reproductive stability, and acceptable grain and biomass productivity.