Abstract RB036152 sugarcane cultivar is known for its high cane yield and elevated sucrose content. In the central-southern region, optimal harvest period extends from July to November. This cultivar is particularly well-suited for mechanized planting and harvesting, demonstrates excellent performance in challenging environments, and shows strong tolerance to major sugarcane diseases. RB RB03615 content centralsouthern central southern region November wellsuited well suited harvesting environments diseases RB0361 RB036 RB03 RB0

ABSTRACT. The success of sugarcane (Saccharum spp.) breeding programs depends on the choice of productive parent lines that have a high industrial yield and are genetically divergent. This study assessed the genetic divergence and population structure of sugarcane accessions that are the parents of the RB05 Series of the Sugarcane Breeding Program of Brazil. The DNA of 82 accessions was evaluated using 36 simple sequence repeat markers. The Jaccard similarity coefficient and Unweighted Pair Group Method with Arithmetic Mean clustering method were used to generate a cluster that was divided into 17 distinct groups derived from probabilistic models. The similarity coefficient used in both cases showed that the degree of similarity varied from 0.4716 (RB971551 x RB965586) to 0.9526 (RB936001 x SP89-1115), with a mean of 0.8536. This result demonstrates a high similarity between the 82 accessions and confirms Wright’s F statistic (0.125), which indicates moderate genetic variability. The less-similar crosses suggest that breeders seek a higher number of crosses using cultivar RB965586, highlighting the RB971551 x RB965586 and RB965586 x RB855511 crosses. The results demonstrate that crosses such as RB936001 x SP89-1115 and RB945954 x RB896342 should be avoided because of their high genetic similarity.

Abstract Cultivar RB036091 is an early-maturing sugarcane with a long period of industrial suitability; in the Central South region of Brazil, harvest is recommended between April and August, and the cultivar is indicated for planting on moderate to highly fertile soils. It is widely adaptable and has a high sugar yield and stability of agricultural yield.

RESUMO A expansão da cultura da cana-de-açúcar na região Centro-Sul tem sido predominantemente em solos arenosos com baixo potencial produtivo. Os objetivos deste trabalho foram avaliar a manutenção do palhiço, consórcio da cana com a braquiária e doses de nitrogênio no cultivo da cana em solo arenoso do Paraná. O experimento foi instalado em condições de campo, situado no município de Paranavaí-PR, na unidade da Rede Interinstitucional para o Desenvolvimento do Setor Sucroenergético (Ridesa). O solo foi classificado como sendo um Latossolo Vermelho-amarelo distrófico. Os tratamentos na cana-planta foram constituídos de um fatorial 4x2, sendo quatro doses de nitrogênio (0, 50, 100 e 150 kg ha-1) e cana consorciada e não consorciada com braquiária. Na ocasião da colheita da cana-planta, implementou-se o palhiço como novo fator para ser avaliado na cana-soca. Os tratamentos da cana-soca foram constituídos de um fatorial 4x2x2, sendo quatro doses de nitrogênio (0, 50, 100 e 150 kg ha-1), cana consorciada e não consorciada com braquiária, e uso do palhiço e o não uso do palhiço. A manutenção do palhiço na superfície do solo pode aumentar o desenvolvimento agronômico da cana e, por outro lado, o consórcio de capim braquiária pode reduzir. A cana-de-açúcar foi responsiva às doses de N e, nas maiores doses, compensou a ausência do palhiço e reduziu a competição entre as espécies.

ABSTRACT The expansion of sugarcane cultivation in the Center-South region of Brazil has led to the use of, mainly, areas with low-yielding sandy soils. In this context, the objectives of this study were to evaluate the maintenance of the sugarcane straw, Brachiaria grass intercropping in sugarcane fields and nitrogen fertilization and on sandy soils in the state of Paraná. The field experiment was installed in the Paranavaí-PR city, at a unit of the Interuniversity Network for the Development of the Sugarcane Sector (RIDESA). The soil was classified as Latossolo Vermelho-amarelo distrófico. The treatments in the plant cane stage, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1) and monoculture or Brachiaria grass intercropping in sugarcane fields were arranged in a 4x2 factorial design. At plant cane harvest, the effect of unremoved straw was included as a new factor to be evaluated in the ratoon crops. The treatments in the ratoon crops were arranged in a 4x2x2 factorial design, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1), monoculture or Brachiaria grass intercropping in sugarcane fields and the presence or removal sugarcane straw. The sugarcane straw on soil surface can increase the agronomic development of sugarcane and, the other hands, Brachiaria grass intercropping in sugarcane fields can reduce. Sugarcane was responsive to N rates and, in the highest rates, compensated the sugarcane straw absence and reduced Brachiaria grass intercropping competition.