Early Detection Cold Markers to Expedite the Sugarcane (Saccharum spp. Hybrids) Breeding

Sugarcane breeding is a lengthy (>10 years) and expensive multilocational effort. Targeted breeding for cold tolerance is particularly challenging under the subtropical climate, where a damaging freeze does not happen every year. This study aimed to develop chemical markers to detect cold tolerance in genotypes, before freeze happens, to expedite the sugarcane breeding. High sucrose and low invert sugars (glucose and fructose) were used as the benchmark chemical traits for cold tolerance. The tolerant variety HoCP04-838 maintained low invert sugars throughout the subfreeze temperatures (inducing stalk cracking) and subsequent temperature increases to >20 degrees C (enhancing juice deterioration). A tyrosine-like fluorescent marker distinguished HoCP04-838 from susceptible varieties including L12-201 and Ho12-615 (p < 0.05). In addition, HoCP04-838 contained the highest trans-aconitic acid in juice before the freeze, and the cultivar rankings persisted after the freeze. Developed markers could offer a rapid method to screen parents and progeny populations for diverse environmental stressors beyond freeze.