Could the ecophysiological basis of sugarcane be of help in improving sugar yield gains?

Abstract

Sugar yield (SY) gains worldwide have been slowing down since the 1980s. This study aimed to identify how this trend could be reversed by exploring the ecophysiological basis associated with yield increments. Nitrogen, water and radiation use efficiencies were explored. Thirteen cultivars were grown during three consecutive cycles at Tucumán, Argentina. Cane yield (CY), sugar content (SC), SY, average-stem-weight (ASW), nitrogen-use-efficiency (NUE) and wateruse-efficiency (WUE) increased linearly with the year of release of the cultivars. Sugar yield was associated with CY, SC, ASW, NUE and WUE (r>0.65; P<0.05), whereas CY was only related to ASW, NUE and WUE (r>0.81; P<0.01). Stem number at harvest was not increased by breeding and was not related to SY and CY. This could be because breeding did not modify the dynamic of generation and mortality of stems. However, breeding modified the canopy architecture of the crop. This was associated with increases in the amount of radiation intercepted by the crop during its cycle; modern cultivars had higher maximum interception and needed fewer days to reach maximum interception than older cultivars. However, sugarcane breeding did not increase the radiation-use-efficiency. In summary, using ecophysiological tools could help breeders to improve SY.