A review of fertility challenges in wheat–perennial rye hybrids: Insights from the successful wheat–annual rye hybrid (triticale)

Abstract

Hybrids of wheat (Triticum aestivum) and perennial rye (Secale cereale x Secale strictum) have shown promising results in enhancing agronomic features such as stress tolerance, perennial growth habit, and yield potential. However, fertility issues persist, posing a significant obstacle to the efficient utilization and successful implementation of hybrid vigor in crop improvement efforts. Fertility challenges, such as sterility and low seed production, are mainly caused by chromosomal mismatches, irregularities during meiosis, and genetic differences between the parent species. These factors disrupt normal gamete development, lower pollen viability, and cause embryo failure, all of which hinder the reproductive potential of the hybrids. Scientists have used multiple approaches to restore fertility, such as using cytogenetic methods to study chromosome behavior, applying polyploidization to stabilize hybrid genomes, and utilizing molecular tools to identify fertility-related genes. This review covers the specific factors that influence fertility in wheat-perennial rye hybrids, covering cytological, genetic, and environmental components. Gaining a better knowledge of the mechanisms underlying hybrid sterility and investigating techniques to increase fertility will significantly progress hybrid breeding efforts and aid in developing hardy perennial cereal crops. The outcomes discussed in this review aim to contribute to future research and assist in creating successful strategies for enhancing hybrid fertility in perennial grain breeding projects.