Desempenho de sete genótipos de cana de açúcar de quinto corte na região sul do estado do Tocantins Performance of seven sugar cane genotypes of fifth cut at south of Tocantins state

This study was conducted to evaluate the performance of seven sugar canes genotypes of fifth cut in relation to plant height, number of culms, biomass and average content of soluble solids (°Brix). The experiment was conducted at the experimental station of the UFT, starting shortly after the first cut cane in July 2011. The experimental design was a randomized block with seven replicates and 4 treatments, the variables subjected to analysis of variance by test (Tukey) at 5% probability characteristic productivity. The characteristics plant height, number of culms biomass and (° Brix) was used regression analysis. The cultivars were: RB72-454, RB83-5486, RB85-5113, RB85-5536, RB86-7515, IAC86-2480, SP79- 1011. For height and number of culms, to the cultivate RB 85-5113 showed higher values. As for productivity, the cultivar RB 85-5536 was better, differing cultivars IAC 86-2480 and 83-5486 RB. The variable (°Brix), the best was the RB83-5486. At conditions of the south of the Tocantins State, exploitation sugarcane show great potential, however, this study indicates the importance of replacing the cultivars after the fifth cut due to loss of vigor.