Djalma Euzébio Simões Neto

Produtividade, eficiência de uso da água e qualidade tecnológica de cana‑de‑açúcar submetida a diferentes regimes hídricos

O objetivo deste trabalho foi avaliar a produtividade de colmos e de acucar, a eficiencia de uso da agua e os atributos tecnologicos de cinco variedades de cana-de-acucar de maturacao precoce e seis de maturacao media a tardia, submetidas ao regime de sequeiro (1.141,4 mm) e a irrigacao plena (1.396,6 mm). Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repeticoes. A produtividade de colmos das variedades RB92579, RB72454 e SP81-3250 apresentou ganhos superiores a 180%, com uso da irrigacao. A irrigacao promoveu aumentos na produtividade de acucar superiores a 200%, nas variedades RB92579 e RB943365. A irrigacao plena proporcionou maior eficiencia de uso da agua, com producao media de 70,2 kg ha-1 mm-1 de colmos a mais em comparacao ao regime de sequeiro. Com excecao das variedades RB72454, RB763710 e RB943365, nao houve diferenca nos atributos tecnologicos entre a irrigacao plena e o regime de sequeiro. As variedades RB92579 e SP81-3250 de maturacao media a tardia se destacam quanto a produtividade de colmos e de acucar e a eficiencia de uso da agua, e sao recomendadas para estudos de resposta a irrigacao pela cana-de-acucar.

Características agroindustriais da cana-de-açúcar em função da adubação fosfatada, em solos de Pernambuco

The P recommendations in Northeastern Brazil are based on research carried out in the decades of 70 and 80, being necessary a modernization in this recommendation, to focus the maximum capacity of P adsorption. Therefore, this work aimed to evaluate agroindustrial sugarcane characteristics in soils in function of phosphate fertilization. Five experiments were carried out at Pernambuco State Forest Zone Region. The soils were: Argisoil Yellow distrocoeso (PAdx); Latosoil Yellow distrofic (LAd); Argisoil Yellow distrofic (PAd); Gleisoil haplic eutrofic (GXve); and Espodosoil carbic duripanic (ESKo). The treatments consisted of seven P doses, determined in function of the maximum adsorption capacity of P. The experimental design was a completely randomized block, with four replications. The sugarcane variety RB863129 was used in PAd, LAd, GXve and EKo soils and RB855536 on PAd soil. The P fertilization increased agricultural and industrial productivities. Total recoverable sugar (ATR) values were not affected by phosphate fertilizer, being more elevated in soils with higher maximum adsorption capacity of P.

Níveis críticos de fósforo em solos cultivados com cana-de-açúcar em Pernambuco

Critical levels of phosphorus in sugarcane soils of Pernambuco State, Brazil Physical, chemical and mineralogical properties of soils are not observed to estimate phosphorus (P) availability in Pernambuco, Brazil. The aim of this work was to determine phosphorus critical levels in distinct soils, using different chemical extractors, considering clay fraction content and quality , and to relate soil physical, chemical and mineralogical characteristics with P critical levels. The soils were classified like: Typic Haplustults; Typic Hapludox; Typic Hapludults; Typic Hydraquents and Typic Haplohumods. Treatments consisted of seven P doses, determined in function of P maximum adsorption capacity (PMAC). The experimental design was in randomized blocks, with four replicates. Samples of soil were collected at lots useful area. This sampling was made 30 days after the plantation and treatments application at 0,0-0,2 m depth. In these samples it was determined P content by the extractors Mehlich-1, Mehlich-3, Bray-1 and

Utilização de marcadores moleculares RAPD e EST's SSR para estudo da variabilidade genética em cana-de-açúcar¹

Molecular markers of the type RAPD and ESTs SSR were used as tools to evaluate the variability, and estimate the genetic divergence between commercial varieties and sugarcane clones from self-pollination. Twenty-three genotypes from the Program for the Genetic Improvement of Sugarcane of the Interuniversity Network for the Development of the Sugar-alcohol Sector (PMGCA/RIDESA), were used in this study. The extraction of genomic DNA followed CTAB methodology, with modifications being made for sugarcane. Eleven RAPD oligonucleotides, obtained from Operon Technologies, and 7 ESTs SRR, found after an extensive review of the literature, were used. Analyses of genetic diversity were carried out using the GENES software. The RAPD markers detected a high degree of genetic polymorphism, producing 61 bands, of which 58 were polymorphic. The ESTs SSR markers amplified 38 alleles, 34 being polymorphic. Three groups being formed with the population studied. Most of the genetic variation was maintained among progeny, indicating the occurrence, for purposes of breeding, of a high degree of genetic variability among the genotypes of each progeny. Through estimated genetic divergence, it was possible to identify divergent parent plants, which could be used in hybridization in order to obtain superior clones with characteristics of interest to the sugarcane industry. The molecular markers RAPD and ESTs SSR were equally efficient in estimating the genetic variability in the genotypes tested, and in preparing crossbreeds to be used in breeding programs.

Adubação fosfatada para cana-de-açúcar em solos representativos para o cultivo da espécie no Nordeste brasileiro

The objective of this work was to evaluate P availability in representative soils for plant cane cultivation in the Brazilian Northeast region, and to establish a new P‑fertilizing recommendation for this crop in these soils. The study was done in five soil types, in Zona da Mata of Pernambuco: Argissolo Amarelo distrocoeso (Ultisol), Argissolo Amarelo distrofico (Ultisol), Latossolo Amarelo distrofico (Oxisol), Gleissolo Haplico eutrofico (Gleisol), and Espodossolo Humiluvico ortico (Spodosol). Seven P doses were evaluated for maximum P adsorption capacity of each soil (solution equilibrium phosphorus, P‑rem). Thirty days after soil fertilization, P contents in soils were determined with the extractors Mehlich‑1, Mehlich‑3, Bray‑1, and anion exchange resin. P critical levels were calculated for each soil and extractor. From P availability ranges, five fertility classes were defined for different clay contents in the soils: very low, low, medium, high, and very high. Mehlich‑1 and anion exchange resin are able extractors to adequately represent soil‑P availability for plant cane cultivation in the evaluated soils.

Presence of orange rust on sugarcane in the state of Pernambuco, Brazil.

Sugarcane leaf rust symptoms were observed on seven month-old plants in March 2012 at Santa Teresa Farm, north coast of Pernambuco, Brazil. Plants were identified as a genotype coded as RBUFRPE0032 developed by the Sugarcane Breeding Program of Universidade Federal Rural de Pernambuco (UFRPE/EECAC). Evaluations under field conditions showed characteristic leaf rust symptoms and high severity. Analysis of symptomatic leaves under the optical microscope at the Plant Pathology Laboratory of UFRPE/EECAC confirmed the presence of fungal urediniospores showing specific characteristics of the fungus. Molecular evaluation by real-time PCR yielded positive results for Puccinia kuenhii. This is the first report of sugarcane leaf rust in Pernambuco. Although the disease has been reported in other Brazilian states, producers and researchers are worried since the behavior of promising commercial varieties and clones from breeding programs directed at the soil and climatic conditions of the state is unknown. The Ministry of Agriculture in Pernambuco was officially informed for notification purposes.

Repeatibility of agroindustrial characters in sugarcane in different harvest cycles

n commercial cultivation of sugarcane, knowledge about the repetition of agroindustrial characters is essential to identify long-lived genotypes in production cycles, which when selected, will contribute to the significant increase in productivity. This work evaluated the agroindustrial performance of 16 sugarcane genotypes in the sugarcane microregion Litoral Norte of Pernambuco in four harvest cycles and the regularity in the repetition of characters. The experiment was conducted in the agricultural area of Sao Jose sugar mill, Igarassu, state of Pernambuco, Brazil. The experiment was carried out following a randomized block design with four replications. The variables evaluated were: tons of POL per hectare (TPH), tons of cane per hectare (TCH), fiber (FIB), adjusted POL% (PCC), soluble solids content (BRIX), and total recoverable sugar (TRS). The variance analysis detected significant differences among the genotypes along the four harvest seasons, indicating genetic variability and possibility of success in the selection of superior genotypes. Estimates of repeatability coefficient point to regularity in the repetition of agro-industrial characteristics allowing to identify genotypes with the highest longevity. The genotypes SP79-1011, RB863129, RB92579, RB813804, RB982559 e RB982613 presented best agroindustrial performance, and two evaluations based on TPH and TCH characters are enough to select superior genotypes with 90% predictability of their actual values.