Desempenho agronômico de variedades de cana-de-açúcar em Dois Vizinhos - Sudoeste do Paraná

Abstract

Sugarcane is among the main agricultural crops of economic importance for Brazil, and the State of Paraná is the fifth largest producer in the country, with emphasis on the Northwest region. This scenario is observed mainly due to the climatic conditions that undermine the cultivation of sugarcane in the regions south of the State in view of the risk of frost. This provides the lack of technical knowledge about the crop in regions such as the Southwest of Paraná, promoting the demand for research that determines which varieties are most adapted to the crop in these environments. The objective of this study aimed to determine the agronomic behavior and the levels of cold damage in sugarcane varieties in plant cane and ratoon cane under the conditions of Dois Vizinhos, Southwest of Paraná. The work was conducted at the Experimental Farm of the Universidade Tecnológica Federal do Paraná - Câmpus Dois Vizinhos, where nine sugarcane varieties with different maturation cycles (early, middle and late) was be cultivated. The planting of the experiment was carried out in October 2018 and evaluations were carried out during the development of the crop to determine the morphological characteristics of interline closing, leaf area, plant height, harvest components such as stalk productivity, fiber, Brix, broth and cold damage rates during two cuts (plant cane and ratoon cane) will be carried out. The assessments started in January of the following year and occur monthly until September, when the cut in the total area was carried out to start the second year of assessments. The varieties of early and medium cycle proved to be more adaptable to the Southwest region, with late-maturing varieties having difficulty in establishment. CTC20 and IACSP95-5000 were the varieties that presented smaller size for both years of evaluation. CTC 9005 was the variety with the greatest productive potential for both years, both in plant and ratoon cane with 163,72 and 201,89 t of stems ha-1, respectively. RB975201 was the least productive variety in cane plant with 78.42 t of stems ha-1. For TBH, CTC9005 and RB966928 were the most productive in plant cane with 28.56 and 27.64 t ha-1, respectively. For ratoon cane CTC9005 was the most productive for TBH with 41,85 t ha-1. However, in the same way that it presented high productive potential, CTC9005 was the variety with the greatest presence of lodging, which makes manual harvesting difficult. The occurrence of severe frosts in the winter of 2019 compromised the leaf area of all studied materials, also increasing the rates of damage by cold, which is contrary to the cycle of cane soca where there was no frost formation. Early and medium cycle varieties allow harvesting at 300 days after planting / harvesting, with peak production potential.