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.

Abstract The sugarcane cultivar RB036066 is medium-maturing and has a long period of industrial suitability; in the South-Central region, harvest is recommended between June and September, and it is indicated for planting on medium to highly fertile soils. The cultivar is widely adaptable and has high sugar yield and stability of agricultural production.

Abstract The sugarcane cultivar RB036088 is late-maturing, harvested from September to November in south-central Brazil, and is recommended for soils with medium to high fertility. It stands out with continuously high sugar yield over the harvests, longevity of the ratoon plants, high tillering capacity and can be harvested mechanically.

Abstract The objective of this study was to identify superior parents for crosses and the best families to breed new clones of energy cane. The best-performing parents were RB867515, RB93509, KRAKATAU, IM76-228, IM76-229, and US85-1008. The heritability and accuracy values for the traits tons of cane per hectare, fiber, and sucrose content indicate high correlation between the predicted genotypic means and observed values, enabling efficient selection of the best cane energy families. The extensive genetic variation detected and the presence of promising seedlings in the selected segregating population indicate the possibility of using new crosses in some clones and even in future commercial plantings. It was possible to identify the best parents involved in the evaluated crosses, and to select, in the best families, seedlings with a high fiber and good sucrose content, seedlings with high fiber and low sugar content, as well as seedlings with the same fiber and sucrose contents as the current cultivars.

O adequado crescimento radicular influencia o crescimento de plantas e o estabelecimento do cultivo. O desenvolvimento vegetal pode ter relação com o tamanho da reserva nutricional de toletes de uma gema (mini-toletes) de cana-de-açúcar e a aplicação de substâncias que estimulam a utilização dessas reservas. Assim, o objetivo consistiu em estudar o uso de substâncias húmicas e do ácido L-glutâmico, aplicados em minitoletes de cana-de-açúcar de diferentes tamanhos no crescimento inicial do sistema radicular e da parte aérea. O estudo foi conduzido em condições de campo, em delineamento inteiramente casualizado, em esquema fatorial (5x3), com três repetições. Os tratamentos foram compostos pela combinação de cinco comprimentos de minitoletes, 0, 4, 8, 12 e 16 cm e três tratamentos: substância húmica, ácido L-glutâmico e da testemunha sem aplicação. Verificou-se que a aplicação de ácido húmico apresentou diferença estatística superior em relação ao ácido L-glutâmico, e este possibilitou aumento quando comparado com a testemunha, para as variáveis: comprimento, área superficial, massa seca do sistema radicular e massa seca da parte aérea. O comprimento da reserva do tolete influenciou significativamente a massa seca da parte aérea e as características do sistema radicular. Também foi observado correlação significativa da biomassa da parte aérea com as variáveis do sistema radicular e com isso verificar as suas interações.

The proper root growth affects the growth of plants and establishment of cultivation. The vegetal development could be related with organic reserve size of 1-bud sett (minicuttings) of sugarcane and the application of substances that stimulate the use of these reserves. Thus, this work aimed study the use of humic substances and L-glutamic acid, applied in sugarcane minicuttings of different sizes and to verify its interactions in the initial development of shoots and root system. The experiment was conducted at the Experimental Station of Paranavaí - PR, in completely randomized factorial design, with five sizes of mini-cuttings being: only bud with node and mini-cuttings with 4, 8, 12 and 16 cm long; undergoing treatments with humic substance and L-glutamic acid, and control (no treated), with three replications. It was concluded that humic acids showed statistically difference higher than the L-glutamic acid, and this enabled an increased compared with control for variables: length, surface area, dry mass of roots and dry weight of shoot. The size of the reserve in the minicuttings significantly influenced the dry mass of shoot and root characteristics. We also observed a significant correlation of shoot biomass with the variables of the root system.

RB966928 is an early to medium maturing sugarcane cultivar and in Central-Southern Brazil it is harvested between April and June; it is recommended for planting in environments with medium to high soil fertility. It stands out with a high ratoon yield and with excellent sprouting in both plant cane and ratoon cane. It is tolerant to the major diseases of economic importance of sugarcane.