RESUMO O objetivo deste estudo foi de avaliar a influência da adubação nitrogenada, do ambiente e cultivares no teor de proteínas, o volume de sedimentação com dodecil sulfato de sódio (SDSS) e no número de queda em trigo. O delineamento experimental foi em blocos ao acaso em esquema de parcelas subdivididas, em quatro repetições foram avaliadas cultivares de trigo IPR Catuara TM, BRS Gaivota, Quartzo e CD 120 em seis manejos do nitrogênio em quatro ambientes. Foram realizadas as avaliações do teor de proteínas, teste de sedimentação com dodecil sulfato de sódio, número de queda e produtividade de grãos. Foi realizada análise de variância conjunta para os quatro ambientes e as médias foram comparadas pelo teste de Tukey, p ≤ 0,05. O efeito do ambiente é superior ao efeito de nitrogênio e de cultivares sobre o teor de proteínas. O incremento no teor de proteínas reduz a produtividade de grãos das cultivares. O SDSS e o número de queda em trigo são influenciados pela interação entre cultivar e ambiente e também pelo manejo do nitrogênio. O teor de proteínas no grão tem baixa influência sobre o volume de sedimentação com dodecil sulfato de sódio, logo o manejo do nitrogênio em cobertura apresenta efeito menos acentuado para essa variável resposta. O número de queda não varia entre cultivares quando o ambiente é propício à germinação na espiga. A utilização de nitrogênio em cobertura influência o número de queda em trigo.

ABSTRACT The aim of this study was to evaluate the influence of nitrogen (N) fertilization, environment and cultivars on the protein concentration, sodium dodecyl sulfate sedimentation test (SDSS) volume and falling number in wheat. The experimental design was a randomized blocks in split plot scheme with four repetions. Four wheat genotypes were evaluated under six N managements in four enviroment (subplots). The wheat genotypes evaluated were IPR Catuara TM, BRS Gaivota, Quartzo and CD 120. Protein concentration, SDS sedimentation test, falling number and grain yield were evaluated. Combined analysis of variance for the four environment was performed and means were compared by Tukey test at p ≤ 0.05. The environmental effect is greater than the genotype and N effects on protein concentration. The increase in protein concentration reduces grain yield of the cultivars tested. SDSS and falling number in wheat are influenced by the interaction between cultivar and environment and also by the N management. The protein concentration of grain has low influence on SDS sedimentation volume, so the topdressing N management has less accentuated effect on this response variable. The falling number does not vary among cultivars when the environment is suitable to pre-harvest sprouting. The use of topdressing N influences the falling number in wheat.

Neste trabalho se objetivou avaliar a aplicação foliar de aminoácidos associada à aplicação de nitrogênio em cobertura, no desempenho produtivo e nas características agronômicas da cultura do milho, cultivado no período da safrinha. O delineamento foi o de blocos ao acaso, em esquema fatorial 4 x 4, com 4 repetições. Foram utilizadas quatro doses de nitrogênio em cobertura (0, 60, 120 e 180 kg ha-1) na forma de ureia e quatro doses de aminoácido (0, 8, 16, e 24 L ha-1) aplicadas via foliar. A cultivar de milho utilizado foi o Pioneer 305 31H. As variáveis analisadas foram teor de nitrogênio foliar, altura de plantas, altura de espiga, diâmetro do colmo, comprimento de espiga, número de fileiras de grãos por espiga, número de grãos por fileira, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O aminoácido não alterou as variáveis analisadas. O nitrogênio incrementou linearmente as variáveis altura de plantas, altura de inserção de espiga, número de grãos por espiga e número de grãos por fileira. O comprimento de espiga, a massa de mil grãos e a produtividade de grãos obtiveram, respectivamente, máxima resposta ao nitrogênio nas doses de 135,3, 157 e 149,5 kg ha-1.

The objective of this study was to evaluate the foliar application of amino acids associated with the application of nitrogen as topdressing on yield performance and agronomic characteristics of corn, cultivated during the latter season. The experimental design was a randomized block design in a 4 x 4 factorial, with 4 repetitions. Four doses of nitrogen (0, 60, 120 and 180 kg ha-1) as urea were used and four doses of amino acids (0, 8, 16, and 24 L ha-1) were applied on leaves. The maize cultivar used was Pioneer 305 31H. The variables analysed were: leaf N content, plant height, ear height, stem diameter, ear length, number of kernel rows per ear, number of kernels per row, number of grains per spike, weight of 100 grains and yield. The amino acids did not alter the analysed variables. Nitrogen increased linearly the variables plant height, height of insertion of ear, number of grains per ear and number of kernels per row. The length of spike, thousand grain weight and grain yield response to nitrogen obtained under maximum doses of 135.3, 157 and 149.5 kg ha-1, respectively.

El piojo harinoso de la yuca, Phenacoccus manihoti (Hemiptera: Pseudococcidae), se alimenta por succión de la savia de las plantas de yuca, causando daño directo por la succión de la savia y la toxicidad de la saliva e indirectamente, favoreciendo el desarrollo de fumagina. Para el establecimiento de un manejo integrado de plagas, es importante conocer la biología de este insecto. Por lo tanto, el objetivo de este estudio fue determinar las caracteristicas biológicas de Ph. manihoti en la yuca. El experimento se realizó con el cultivar Santa Helena. Las plantas se mantuvieron en un sitio semi-climatizado con una temperatura media de 25 °C. Se colocaron aproximadamente 20 huevos recién depositados en las cuatro hojas apicales. Después de la eclosión de los huevos, se dejó una sola ninfa del primer instar por hoja. Las cochinillas se evaluaron diariamente, registrando el tiempo de muda y la mortalidad de las ninfas y la fecundidad y la longevidad de las hembras adultas. A partir de los datos biológicos obtenidos, se realizó la tabla de vida de fertilidad. El estudio tuvo 90 repeticiones. La duración del huevo, ninfa del primer instar, segundo instar, tercer instar y longevidad de la hembra adulta fueron 7,7; 6,9; 4,9; 5,7 y 20,7 días, respectivamente. El ciclo de vida fue de 45,22 días, y la fecundidad fue de 247 huevos por hembra. La tasa reproductiva neta (Ro), tiempo generacional medio (T), tasa intrínseca de crecimiento (r m) y el tiempo de duplicación (D T) fueron 223,640 hembras/hembras, 36,500 días, 0,145 hembras/hembras/día y 4,780 días, respectivamente. La tasa máxima de aumento de la población fue en el día 36.

The cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) feeds by sucking the sap of cassava plants, causing damage directly by sucking the sap and contaminating the plant with its toxic saliva and indirectly by favoring the development of sooty molds. To establish an integrated pest management program, information about the biology of pest species is basic. Thus, the objective of this study was to determine some biological characteristics of Ph. manihoti on cassava. The experiment was conducted using Santa Helena cultivar which was kept in a semi-heated room at an average temperature of 25 °C. Approximately 20 newly oviposited eggs were placed on four apical leaves of each plant. After the eggs had hatched, only one first-instar nymph was left per leaf. The mealybug nymphs were examined on a daily basis; information on molting time was recorded and data on mortality and oviposition were used to construct a fertility life table. The experiment was conducted with 90 replicates. The average duration of the egg, first-instar, second-instar, third-instar nymph and the adult stages were 7.7, 6.9, 4.9, 5.7 and 20.7 days, respectively. On average, the total life cycle lasted 45.22 days, and each female was able to produce a total of 247 eggs. The net increase rate (Ro), mean generation time (T), intrinsic rate of increase (r m) and doubling time (D T) were 223.640 female/female, 36.500 days, 0.145 female/female/day and 4.780 days, respectively. The maximum rate of population increase occurred on the 36th day.

The levels of testosterone (T) and 11-ketotestosterone (11-KT) of the South American pacu Piaractus mesopotamicus were determined by radioimmunoassay during two stages of the reproductive cycle, i.e., resting and maturation, and the gonadosomatic index (GSI) was calculated. The highest levels of T and 11-KT were reached during the maturation stage (T = 2400 ± 56 pg/ml; 11-KT = 2300 ± 60 pg/ml) and lower levels were maintained during the resting period. The rise in androgen levels occurred with the appearance of spermatozoa in the maturation stage, when GSI was highest