Accumulation of Secondary Products in Drought-Impacted Sugarcane (<i>Saccharum</i> spp. Hybrids) Breeding Lines

Over 60% of total land areas in Louisiana had moderate to exceptional drought during the 2023 sugarcane growing and harvesting season. The processable quantity and quality of harvested sugarcane varieties depend on their stress tolerance. The drought caused a higher amount and aromaticity (≈100 nm red-shift in fluorescence emission wavelength) of polyphenol-like secondary products in breeding lines. Cluster analysis of 33 varieties with reported degrees of cold tolerance indicated fluorescent secondary products to be the potential chemical marker. These chemical fingerprints could be used to evaluate the first-line clones of unknown cold or drought tolerance. Partial least-squares calibrations were built for two markers: trans-aconitic acid and tyrosine-like fluorophore. The marker contents in 330 genotypes varied by over 5-fold, and some clones contained several-fold higher markers than the commercial varieties. The developed regression models could be used for the marker-assisted selection of sugarcane breeding lines to increase the tolerance against winter freeze and summer drought.