Biomass production of sugarcane cultivars and early-generation hybrids

Sugarcane ( Saccharum L. spp. hybrids) is a vegetatively-propagated, perennial crop cultivated primarily for sucrose production. The biomass production of interspecific and intergeneric hybrids is assumed to surpass that of cultivars, but there have been few statistical comparisons. The objectives of this study were to determine effects of plant-cane and ratoon crops on biomass yield components for two sugarcane cultivars and early-generation hybrid derivatives (Experiment 1), and to determine the effect of backcross breeding on biomass yield components (Experiment 2). Two cultivars and 47 hybrid derivatives (F 1-BC 2) were evaluated in replicated, single-row plots near Houma, Louisiana, for four annual harvests (Exp. 1). Thirty random clones from F 1, BC 1, BC 2, BC 3, and elite generations were evaluated in replicated single-rows in the plant-cane crop (Exp. 2). Fresh-weight biomass yield of one hybrid clone, US 74-69, was 307 Mg ha −1 (Exp. 1). Mean fresh-weight biomass yield of hybrids was nearly 50 Mg ha −1 yr −1 greater than that of cultivars ( P ≥ 0.05). Fresh-weight and dry-matter yields decreased linearly across crops (plant-cane through the fourth-ratoon crop) for cultivars, but there was no consistent trend for the early-generation hybrids. Backcrossing (F 1 through BC 3 generations) to elite parents resulted in a marked reduction of many important biomass yield components, including fiber concentration, solids concentration, and stalk number (Exp. 2). No backcross or elite progeny surpassed F 1 progeny in fresh-weight or dry-matter yields ha −1. This study confirmed that early-generation sugarcane hybrids have great potential for high biomass production. Biomass production might be improved in later-generation hybrids by selecting for stalk number and fiber concentration.