Walter Quadros Ribeiro Júnior

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.

Genetic diversity of irrigated barley based on molecular and quantitative data and on malting quality

The objective of this work was to determine the experimental precision in the evaluation of forage turnip fresh matter weight, in scenarios formed by combinations of plot sizes and number of treatments and replicates. Data from fresh matter weight of 3,456 basic experimental units of 0.5×0.5 m (0.25 m2) were used. The scenarios (1,728) were planned and formed by the combinations of six plot sizes (0.25, 0.50, 1.00, 1.50, 2.00, and 2.25 m2), i treatments (i = 5, 6,..., 20), and r replicates (r = 3, 4,..., 20). For each scenario, 2,000 resamplings were carried out, with replacement. The average of these 2,000 estimates, in each scenario, was calculated for the least significant difference by Tukeys test, the variation index, and the experimental coefficient of variation. These statistics, in that order, are adequate to evaluate the experimental precision. To evaluate turnip fresh matter weight, in experiments in a completely randomized design with 5 to 20 treatments and five replicates, plots with the size of six basic experimental units (1.50 m2) are sufficient to identify significant differences between treatments - less than or equal to 36.88% of the overall mean -, by Tukeys test at 5% probability, in experiments in a completely randomized design with 5 to 20 treatments and five replicates.

First record of damage by an insect pest in a commercial amaranth crop in Brazil

Insect pests have not been recorded for amaranth (Amaranthus cruentus L.) in Brazil. Generalized plant lodging was observed after the grain-filling period in an irrigated commercial amaranth crop (7 ha), located in Cristalina, state of Goias (Brazil), which was cultivated between Aug. and Dec. 2009. Almost all sampled plants presented internal galleries bored by lepidopteran larvae. The larvae were reared, and the adults were identified as Herpetogramma bipunctalis (F.) (Crambidae). This is the first report of an insect pest causing significant damage in a commercial amaranth crop in Brazil, which indicates the need to develop pest management strategies in order to support the increased production in Brazil.

Amaranth, quinoa, and millet growth and development under different water regimes in the Brazilian Cerrado

The objective of this work was to evaluate the growth dynamics of the cover plants amaranth (Amaranthus cruentus), quinoa (Chenopodium quinoa), and millet (Pennisetum glaucum) in a Typic Acrustox, under different water regimes in the Brazilian Cerrado. The cultivation was carried out in the winter, with reduced rainfall, which facilitated the application of varying irrigation depths to the different crops. Water regimes denominated lower, lower middle, upper middle, and upper – corresponding to 217, 386, 563, and 647 mm water depths, respectively – were tested by means of an irrigation bar composed of sprinklers with different flow rates. Plant growth was quantified by weekly collections. Amaranth was the most responsive plant to water. Quinoa showed the best performance in the treatment with the upper-middle water level among the other evaluated species. Millet showed thermal sensitivity for cultivation in the winter, making grain production unfeasible; however, it showed exceptional ability to produce biomass even in the treatment with higher water deficit.