Vanoli Fronza

Adaptabilidade e estabilidade de genótipos de trigo irrigado no Cerrado do Brasil Central

O objetivo deste trabalho foi estimar a adaptabilidade e estabilidade de genotipos de trigo irrigado, nas condicoes do Cerrado do Brasil Central. O rendimento de graos de cinco cultivares e nove linhagens de trigo irrigado foram aferidos no ensaio de valor de cultivo e uso. Os ensaios foram conduzidos nos anos de 2005 e 2006, em seis locais em Minas Gerais, tres em Goias e um no Distrito Federal. Os dados de rendimento de graos foram submetidos a analise de variância individual e a analise de variância conjunta, para a estimativa dos parâmetros de adaptabilidade e estabilidade. Verificaram-se diferencas significativas, entre os genotipos, em 14 dos 16 ambientes avaliados. Nenhum dos genotipos avaliados apresentou o comportamento ideal preconizado pelo metodo de Cruz e colaboradores. Destacaram-se a cultivar BRS 264 e a linhagem CPAC 02167, pela superioridade em todas as condicoes do Cerrado do Brasil Central (adaptabilidade geral). Entre os demais genotipos avaliados, destacaram-se as cultivares BRS 207 e EMBRAPA 22, responsivas a melhoria das condicoes ambientais, e as cultivares BRS 254 e EMBRAPA 42, pela adaptabilidade especifica a ambientes desfavoraveis ao cultivo de trigo irrigado.

Características produtivas do trigo em função de fontes e doses de nitrogênio

Nitrogen fertilization is an important management practice in grasses and quite complex, due to several factors which influence it, such as climatic conditions, cropping systems and available levels and sources. This study aimed at evaluating the effect of topdressing nitrogen (N) sources and levels on the productive characteristics of wheat ( Triticum aestivum L.) grown after soybean, under no-till system. The experiment was conducted in an Oxisol, in Londrina, Parana State, Brazil. The experimental design was randomized blocks, in a 3x4 factorial scheme, with four replications. As topdressing N sources, urea, urea + urease inhibitor (NBPT) and polymer-coated urea were evaluated, in 2008, and urea, urea + urease inhibitor (NBPT) and ammonium sulfate, in 2009, in four doses (0.0 kg ha -1 , 40.0 kg ha -1 , 80.0 kg ha -1 and 120.0 kg ha -1 of N) applied 20 days after emergence. Plant height, lodging percentage, mass of 1,000 grains, grain yield and hectoliter mass were determined, and results showed that increased topdressing N levels promoted plants lodging, decreasing the mass of 1,000 grains, yield and hectoliter mass. The N sources did not affect the yield of the BRS Pardela cultivar grown after soybean.

Genetic and environmental contributions to increased wheat yield in Minas Gerais, Brazil

Producers need wheat cultivars adapted to the predominant climate conditions of the end of the rainy period. Having this in mind, EPAMIG (Agriculture and Livestock Research Institute of Minas Gerais) has been developing a wheat genetic improvement program since 1976, and the estimates of the genetic improvement established by the breeding programs could be useful to quantify their efficiency. This study focused on the quantification of the genetic progress achieved by these improvement programs of dryland wheat in the Brazilian-savanna between 1976 and 2005. The efficiency of these programs was evaluated based on grain yield data of VCU (Value for Cultivation and Use) trials conducted at ten locations in the Minas Gerais State, Brazil. The mean estimated genetic progress for mean grain yield between 1976 and 2005 was 37 kg ha-1 year-1. The genetic yield gain in the study period indicates that the improvement programs of dryland wheat in the Brazilian-savanna are effective. Besides the marked contribution of genetic gain, the environmental and technological improvements were also relevant for the yield, accounting for 47.4% of the total progress in the period. The improvement programs of dryland wheat resulted in a genotype renovation rate of 35% over the years.

Formas de ureia e doses de nitrogênio em cobertura na qualidade fisiológica de sementes de trigo

Besides increasing productivity, nitrogen fertilization may have positives effects on seed physiological quality. The objective of this study was to evaluate the effect of different forms and levels of urea in top dressing fertilization on the physiological quality of wheat seed genotypes. Seeds of three wheat genotypes (BRS 208, BRS Pardela and IWT 04008) were evaluated for four levels of nitrogen fertilization (0, 40, 80 and 120 kg.ha-1) in three forms of urea (conventional urea, urea with urease inhibitor and protected urea). The nitrogen fertilization was applied during tillering, 20 days after emergence. The seed nitrogen content, 1000 seed mass, germination and vigor (germination first count, cold test, seedling emergence in the field, dry weight of seedlings, accelerated aging and electrical conductivity) were evaluated. The IWT 04008 line and the cultivar BRS Pardela had seeds with a higher physiological quality than those of the cultivar BRS 208. The forms of urea and levels of nitrogen in topdressing did not affect seed physiological quality of the different wheat genotypes.

Detection of adventitious presence of genetically modified seeds in lots of non transgenic soybean 1

The difficulty on identifying, lack of segregation systems and absence of suitable standards for coexistence of non trangenic and transgenic soybean are contributing for contaminations that occur during productive system. The objective of this study was to evaluate the efficiency of two methods for detecting mixtures of seeds genetically modified (GM) into samples of non-GM soybean, in a way that seed lots can be assessed within the standards established by seed legislation. Two sizes of soybean samples (200 and 400 seeds), cv. BRSMG 810C (non-GM) and BRSMG 850GRR (GM), were assessed with four contamination levels (addition of GM seeds, for obtaining 0.0%, 0.5%, 1.0%, and 1.5% contamination), and two detection methods: immunoassay of lateral flux (ILF) and bioassay (pre-imbibition into 0.6% herbicide solution; 25 oC; 16 h). The bioassay is efficient in detecting presence of GM seeds in seed samples of non-GM soybean, even for contamination lower than 1.0%, provided that seeds have high physiological quality. The ILF was positive, detecting the presence of target protein in contaminated samples, indicating test effectiveness. There was significant correlation between the two detection methods (r = 0.82; p ≤ 0.0001). Sample size did not influence efficiency of the two methods in detecting presence of GM seeds.

Divergência genética em trigo de sequeiro por meio de caracteres morfoagronômicos

Genetic divergence in rainfed wheat based on morphoagronomic traits Wheat cultivation in rainfed conditions is a good option for regions in Minas Gerais with altitudes above 800 m. The objective of this study was to estimate the genetic diversity of eleven wheat genotypes grown in rainfed conditions, using multivariate analysis based on six morpho-agronomic traits to identify which genotypes have potential for hybrid combinations. The treatments were arranged in a randomized complete block design with four replicates. The experiments were carried out during the wheat cropping season 2007/2008. Great variability was found among the wheat genotypes evaluated in rainfed conditions. The genotypes IAC 289-L22 and IAC 289-L4 were the most similar. The genotypes CD 113 and EP 011106 were the most diverging and the most promising for breeding towards generating material adapted and with good characteristics for rainfed cultivation.