Morpho-physiological bases of biomass production by energy cane and sugarcane: A comparative study

Abstract

Using the same production system as sugarcane, energy cane (Saccharum spp. hybrid, as sugarcane) can produce more biomass, which can be associated with its high tillering and a vigorous root system with rhizomes. These traits enable energy cane to capture natural resources efficiently and convert more energy into biomass than sugarcane. Our aim is to understand the morpho-physiological bases of biomass production by energy cane. We evaluated the efficiencies of light interception and light conversion into biomass in a field experiment, measuring morphological and physiological traits of energy canes (Vertix 2 and Vertix 3) and sugarcane (IACSP95-5000). When plants have a low leaf area index (< 4 m2 m−2), the high tillering of energy cane increases the efficiency of light interception. High leaf insertion angles also favored light interception by canopies with high tiller density, as one found in Vertix 3. However, high tiller density likely caused excessive self-shading in energy cane canopy and then energy canes exhibited similar or lower photosynthetic activity than sugarcane, depending on environmental conditions. All three genotypes faced severe water stress during the ratoon cycle, but energy cane was less sensitive when considering light conversion efficiency and biomass yield.