Harvest index and the components of biological yield in sugarcane

Sugarcane has emerged as a new and potential source of power and bioethanol. Harvest index is a useful parameter to assess the suitability of different varieties for various end-uses. Field studies on harvest index were carried out involving sugarcane varieties and elite genotypes representing the varietal spectrum of subtropical India. The relative contribution of various components of biological yield, such as leaf, stalk and root biomass showed substantial differences among varieties. Harvest index for cane yield was found to vary between 66–81% for the commercial hybrids. The harvest index for sugar yield followed more or less a similar trend. Results highlighted the positive impact of inter-specific hybridization, as the current varieties had higher harvest index than the accessions of the parental cultivated species, namely, Saccharum officinarum, S. barberi and S. sinense and the wild species, S. spontaneum. The extent of variability for this important parameter provides scope for further improving the assimilate partitioning without jeopardizing the adaptability of sugarcane varieties under North Indian agro-climates.