RESUMO
The forecast of a growing energy demand in the coming years has aroused particular interest in biomass for energy cogeneration, to diversify the energy matrix by using clean and renewable sources. To meet the new demands of the sugarcane industry, this study evaluated the agronomic performance and estimated genetic parameters for yield traits in sugar- and energy cane families derived from planned crosses. The cane families were assessed in the northwest of the State of Paraná, county of Paranavaí, in a randomized complete block design, with three replications. The evaluations were carried out 12 months after the first cut, in the ratoon cane cycle, in December 2014, under very unfavorable conditions for the crop, due to the low fertility and water-holding capacity of the soil. Besides, the crop was evaluated at the end of the harvest, when the agricultural and industrial quality of the crop is reduced. The following traits were evaluated at the plot level: soluble solids content, apparent sucrose content (PC), fiber content, tons of cane per hectare, tons of sucrose per hectare (TSH), and tons of fiber per hectare (TFH). High genetic variability was observed for all evaluated traits, with accuracy estimates from 0.69 (TSH) to 0.92 (PC), and high heritability ââ(up to 0.84), indicating the possibility of genetic progress. The sugarcane families derived from crosses of Saccharum spontaneum and Saccharum robustum species with sugarcane hybrids had the highest fiber contents. Highest sugar contents were found in sugarcane families resulting from crosses of sugarcane clones and conventional cultivars. The TSH means were highest in the families F160 x MEX68-200 and RB855156 x RB987935. The highest genotypic mean for TFH was observed in the special polycross involving cultivar RB036066 with S. spontaneum accessions as pollen donors.
