Field assessment of genome edited, low asparagine wheat: Europe's first CRISPR wheat field trial.

We reported in this journal in 2021 the generation of wheat genotypes in which the asparagine synthetase gene, TaASN2, had been ‘knocked out’ using CRISPR-Cas9 (Raffan et al. 2021). The editing had been achieved by introducing genes encoding the Cas9 nuclease, four guide RNAs (gRNAs) and a Bar marker gene into wheat (Triticum aestivum) cv. Cadenza. Here we report the results of a field trial of Line 178.35, an A genome null for TaASN2, and total nulls, 23.60 and 23.75 (Raffan et al., 2021). Also included were four AB genome nulls, referred to as TILLING lines 1-4, derived from a selected line of a mutant population produced by ethyl methanesulphonate treatment of wheat cv. Cadenza seeds (Rakszegi et al., 2010). The mutated TaASN2-A2 gene from this line was backcrossed into the cv. Claire background to generate AB genome nulls (cv. Claire lacks a B genome TaASN2 gene due to a ‘natural’ deletion (Oddy et al., 2021)).