Association of Agronomic, Physiological Traits and Biomass of a Diverse Set of Sugarcane Genotypes under Varied Early Season Droughts

Abstract

Background: Recently, multipurpose and biomass canes have become important in breeding. However, biomass sampling is limited in early generation selection. The surrogate traits that represent biomass performance need to be established, especially using non-destructive sampling. Therefore, the objective of this study was to determine the correlation between agronomic and physiological traits and the biomass of a diverse set of sugarcane genotypes under different drought durations. Methods: The experiment was conducted under field conditions and arranged in a split plot in a randomized complete block design with four replications. The main plot was represented by three drought durations: no water stress, short-term drought and long-term drought and the subplot consisted of six sugarcane genotypes. Samples were collected at 3, 6, 8 and 12 months after transplanting to determine biomass and nondestructive agronomic and physiological traits. A simple correlation was used to determine the relationship between biomass and physiological and agronomic traits. Result: In both field capacity and long drought conditions, 3 months after transplanting, there was a positive correlation between canopy height and biomass and between green leaf number and biomass. The non-destructive leaf area index was a trait that contributed to biomass at 6 months after transplanting under non-water stress conditions. At 8 months after transplanting, a positive relationship between canopy height and biomass was found under short drought and long drought conditions and green leaf number was also related to biomass under field capacity conditions. Biomass at the harvesting stage contributed to canopy width in sugarcane under field capacity conditions. Non-destructive traits in this experiment, such as canopy height and green leaf number, could be used as indirect measurements to reflect the biomass performance under field capacity and long drought conditions at the tillering and physiological maturity phases. For the elongation phase, the non-destructive leaf area index was an altered characteristic that indirectly determined biomass. This information will be useful as an alternative measurement to indicate biomass in the breeding program for drought resistance at the early growth stage.