Chemical ripeners increase early season sugar content in a range of sugarcane varieties

Ripening in sugarcane refers to an increase in sugar content on a fresh weight basis before commercial harvest. Certain chemicals are applied to cane in commercial fields in some countries to accelerate ripening and improve profitability of sugar production. However, responses have usually been reported to be variety and environment specific. We examined changes in the sucrose content in the juice extracted from 43 Australian sugarcane (Saccharum spp. hybrid) varieties in response to 4 ripener treatments in the Burdekin region in northern Queensland over 2 years. The 4 treatments applied were ethephon (as Ethrel®) + fluazifop-P butyl (as Fusilade®), Fusilade® alone, glyphosate (as Weedmaster® Duo), and haloxyfop-R methyl (as Verdict®). These treatments were applied in March–April each year and compared with an untreated control. Of particular interest was whether economic responses are possible for Australian varieties harvested in the May and June period when sugar content in cane is usually low. Increases in sucrose (measured by pol) levels in cane juice were observed after combined application of Ethrel + Fusilade (E+F) and after application of glyphosate, although the result for the latter varied between years. These results suggest that opportunities exist in the Australian industry to improve the profitability of early-harvested sugarcane crops, but further research is required to quantify effects on cane yield and responses in diverse environments