Unravelling mechanisms that govern meiotic crossover formation in wheat

Abstract

Wheat is a major cereal crop that possesses a large allopolyploid genome formed through hybridisation of tetraploid and diploid progenitors. During meiosis, crossovers (COs) are constrained in number to 1–3 per chromosome pair that are predominantly located towards the chromosome ends. This reduces the probability of advantageous traits recombining onto the same chromosome, thus limiting breeding. Therefore, understanding the underlying factors controlling meiotic recombination may provide strategies to unlock the genetic potential in wheat. In this mini-review, we will discuss the factors associated with restricted CO formation in wheat, such as timing of meiotic events, chromatin organisation, pre-meiotic DNA replication and dosage of CO genes, as a means to modulate recombination.

Meiotic instability and irregular chromosome pairing underpin heat‐induced infertility in bread wheat carrying the Rht‐B1b or Rht‐D1b Green Revolution genes

“…3a; Table S5; Kruskal-Wallis, Dunn's post hoc test, H(5) = 59.602, P < 0.001). Crossover assurance (Desjardins et al, 2020(Desjardins et al, , 2022Higgins et al, 2022;Pochon et al, 2022) was impaired, seen in the appearance of univalent chromosomes (Figs 3, S4; Table S5). Contingency tables followed by Chi-squared tests indicated a nonequal incidence of cells with univalent chromosomes within the control and heat-treated meiocytes of the WT, Rht-B1b and Rht-D1b lines (v 2 (5) = 26.452, P < 0.001; Fig.…”