Relative contribution of genetic and environmental effects on non-sugar compounds of cane juice

Abstract

The juice of the sugar cane is composed of sugars, water and insoluble substances referred to as non-sugar compounds. Both sugar and non-sugar compounds are important in the factory because they are responsible for adverse effects on the quality and recovery of sucrose. Increases in the ash and starch contents may affect sucroserecovery and crystallization, while low phosphate concentrations (<300 mg/kg) may cause clarification defects. On theother hand, anthocyanin and phenolic compounds affect juice color and the settling velocity. The relative contributions of genotypic, environmental and interaction effects on the total variability of these non-sugar compounds and theirgenetic correlations were assessed. Determinations associated with non-sugar compounds were performed on a set of 10 genotypes evaluated across six sites of the Sugarcane Breeding Program of Tucumán, Argentina. Starch, ash, phosphates,phenols and color of sugarcane juice were analyzed during the beginning of harvest season in three consecutive years. For each variable, a mixed linear model was adjusted in order to estimate variance components associated with genotypeeffects, environmental effects and their interaction on the total trait variability. Genetically determined correlations were assessed through biplot analysis. Ash, starch and juice colour were associated with the genotype effect with contributions of 58%, 52% and 43% of non-error variability, respectively. These three variables showed negative genetic correlationswith sucrose content. In the case of phosphate and phenolic compounds, the environment was the principal source of variation. Therefore, ash and starch contents and juice colour would be the main determinants associated with non-sugar compounds to be considered in the characterization of genotypes according to industrial quality.