Juice chemical properties of 24 sorghum cultivars under varying levels of sugarcane aphid (Melanaphis sacchari) infestation

Abstract Sugarcane aphids [ Melanaphis sacchari (Zehntner)] have become a significant pest of grain, forage, and sweet sorghum Sorghum bicolor (L.) Moench] in the USA recent years. However, effects sugarcane aphid damage on juice quality not been well studied. A three-year (2015–2017) field study was conducted at Tifton, GA to assess planting date (April, May, or June planting) cultivar responses (24 cultivars) sorghum. Aphid ratings were measured all three years cumulative days 2016 2017. Cumulative (ln scale) (relative marginal effect) correlated five six plantings. Stem collected maturity from seven plantings for chemical analyses, which included HPLC, fluorescence excitation-emission spectrophotometry with parallel factor analysis (EEM/PARAFAC), cyclic voltammetry (CV). negatively sugar-related traits, particularly brix total sugars. In four plantings, negative correlations ( r ≤ −0.493) between trans- aconitic acid concentration observed. Fluorescence electrochemical properties related presence polyphenols also showed damage, resistant landrace No. 5 Gambela. These secondary metabolites may play role resistance tolerance. Stability revealed that more tolerant cultivars able maintain high concentrations sugars trans -aconitic across environments.