The USDA has bred a line of plants which produce inherently fire-resistant white cotton fibres. The breeding is selection, without genetic modification or gene manipulation. 257 interbred lines from 11 initial parent lines already were used (Multi-generational Advanced Generation InterCross = MAGIC methodology). The parent lines all produced flammable cotton. Using MCC (microscale combustion calorimetry), five lines with lower heat release were identified. Fabric c. 100 g/m2 made from cotton from four of these showed to be self-extinguishing under ASTM D1230-17 (45°, open flame). The research analysed genomes of the cotton lines, identifying chromosome/gene positions common to the four fire-resistant lines, but not found in other lines. There was no investigation of chemicals present in the fire-resistant cotton plants, but not in others. One of the identified candidate genes has already been associated with fire resistance in brown cotton plants and is involved in flavonoid synthesis: these ring-based carbohydrates are considered to contribute to the FR properties of tannin. However, this gene alone did not explain the fire performance of the four identified lines. The authors suggest that the genes identified as contributing fire resistance would not modify agronomic performance or other cotton textile characteristics, but this was not experimentally tested.
“Flame resistant cotton lines generated by synergistic epistasis in a MAGIC population”, G. Thyssen et al., USDA (US Dept. of Agriculture), PLoS ONE 18(1): e0278696. https://doi.org/10.1371/journal.pone.0278696