Desempenho de genótipos de cana-de-açúcar em cinco locais no Rio Grande do Sul

Abstract

Sugar cane is very important in the state of Rio Grande do Sul since it is associated with the activities carried out by family agriculture, being used for commercial purposes such as production of cachaça (white lightning), muscovado, molasses, brown sugar and alcohol, and is used for consumption on the property, or informal marketing of products. The culture is strongly influenced by meteorological variables: air temperature, solar radiation and rain, which directly interferes with the productivity of both stems and sugar. Therefore, the interaction between genotype and environment is one of the main factors to be evaluated in the development of a production system. In this sense, the objective of this study was to evaluate the performance of sugar cane genotypes of early and mid-late cycles in different environments in the state of Rio Grande do Sul. The variables evaluated were: ton of stems ha-1 (TCH), ton of total soluble solids ha-1 (TSSTH), efficiency of the use of global solar radiation production (Eph Rs), maturation and cold tolerance of genotypes. For the analysis of adaptability and stability of the genotype to the test environments, it was used the AMMI methodology (analysis of additive main effects and multiplicative interactions), based on the TCH, TSSTH and Ef Rs variables. The results indicate the occurrence of interaction between genotype and environment, with stable genotypes and broad adaptation to test environments. The highlights among the genotypes were RB975932 (G12) of early cycle with 124.3 tons of stems ha-1, 24.8 tons of total soluble solids ha-1 and production efficiency of 2.20 g MJ-1, and the RB996527 (G23) of mid-late cycle with 125.3 tons of stems ha-1, 24.0 tons of total soluble solids ha-1 and production efficiency of 2.22 g MJ-1, which showed superiority in stems, sugar and efficiency of the use of solar energy production and stability in relation to their respective witnesses varieties RB855156 (G11) and RB867515 (G25). Considering cold tolerance, both early and mid-late cycle genotypes presented differentiated behaviors with scores from 1 (live button) to 5 (dead button), as well as maturation with values ranging between 13,8 and 23,4 ° Brix. The higher productivity test environments for both genotypes of early and mid-late cycles were São Luiz Gonzaga (A6 - 1st stem), Santa Rosa (A7 - cane plant) and Santa Rosa (A8 - 1st stem) with average yields above the general average of environments.