Path Analysis for Selection of Saccharification‐Efficient Sugarcane Genotypes through Agronomic Traits

Sugarcane (Saccharum spp.) bagasse is recognized as a promising feedstock for cellulosic ethanol production. The development of high‐quality crop cultivars through plant breeding is a way to improve feedstock quality. This study aimed to directly and indirectly quantify the effects of agronomic characteristics on the saccharification of sugarcane bagasse samples and to identifying the characteristics that can be used as reliable tools for the selection of genotypes for a better biofuel feedstock. The lignin content was determined in bagasse samples of 286 clones from 13 half‐sib families. Twenty clones showing a more contrasting lignin content were analyzed for the cellulose and hemicellulose composition in bagasse. They differed statistically for cellulose and hemicellulose contents and also for the efficiency of cellulose to glucose conversion. Clones with the highest dry biomass content also had the highest fiber content and were grouped among the clones exhibiting the highest lignin content. Lignin content was statistically significant and positively correlated with fiber (r = 0.485, p < 0.05) and plant biomass (r = 0.654, p < 0.01), and hemicellulose content was statistically significant and positively correlated with number of internodes (r = 0.623, p < 0.01). Lignin content and plant biomass had large negative direct effects (0.405 and 0.784, respectively) on glucose released by enzymatic hydrolysis. Variation among clones for plant productivity parameters and chemical composition of bagasse could be exploited by breeding to increase the amount of cellulosic ethanol produced. Lignin content and plant biomass were the most important components with direct and negative influences on the conversion of cellulose to glucose.