Teores de açúcares de quatro genótipos de cana-de-açúcar em diferentes porções do colmo durante a fase de maturação

Abstract

This study aimed to analyze the content of soluble sugars during the maturation phase and assess technological indices and productivity of four genotypes of sugarcane irrigated in the region of Rio Largo-AL. The experiment was conducted in a randomized block design, factorial 4 x 2 x 5, consisting of four genotypes (RB92579, RB98710, RB99395 and RB961003), two portions of the culm (internodes from 1 to 4 and internodes of 5 to 8) and sampling times (82, 49, 25 13 and 3 days preceding the harvest), with three replicates. This was installed in the field in the growing area of the Center for Agrarian Sciences, Federal University of Alagoas, under drip irrigation. At 25 days preceding the harvest, irrigation was suspended. After 82, 49, 25 13 and 3 days preceding the harvest, three stems of each genotype of sugarcane by repeating forming the samples were removed, portions of which two were withdrawn: internodes from 1 to 4 and internodes of 5 to 8, used to extract the juice, and this quantified the concentrations of fructose, glucose and sucrose in HPLC and the Brix reading on portable digital refractometer. To determine the technological indices and productivity were used culms harvested a pair of 5 m length of line sampling area, which were weighed and sent to the laboratory of Usina Santa Clotilde, located in Rio Largo-AL. Analyses of variance were performed and means were compared by Tukey test at 5 % probability, and data analysis of sugars in split plot. Internodes 1 to 4 showed the highest levels of reducing sugars, while the largest accumulation of sucrose and total soluble solids occurred in the internodes 5 to 8. The RB99395 genotype showed more stability in the levels of sugars during maturation of sugarcane.