Universidade Federal de Viçosa

About: Universidade Federal de Viçosa is a education organization based out in Viçosa, Brazil. It is known for research contribution in the topics: Population & Dry matter. The organization has 16012 authors who have published 26711 publications receiving 353416 citations.

Impact of integrated pest management on the population of leafminers, fruit borers, and natural enemies in tomato

Abstract: The objective of this work was to evaluate the impact of integrated pest management (IPM) in the productivity of the tomato and in the populations of leafminers, fruit borers, and natural enemies in tomato crops. The treatments were calendar (spraying twice weekly with insecticides and fungicides), IPM (spraying when action thresholds were achieved), and control (no pesticide was applied). IPM was the most efficient system of pest control due to presenting similar productivity and 65.6% less pesticide applications than in the calendar. The attack of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and Liriomyza spp. (Diptera: Agromyzidae) to the leaves only achieved the action threshold in the final phase of the cultivation. The main fruit borer was Neoleucinoides elegantalis (Guen.) (Lepidoptera: Crambidae), followed by T. absoluta and Spodoptera eridania (Cr.) (Lepidoptera: Noctuidae). The natural enemy populations were severely reduced by excessive pesticide applications. Predators were more abundant than parasitoids. The most abundant predators were Araneidae, Anthicus sp. (Coleoptera: Anthicidae), Cycloneda sanguinea larva (L.) (Coleoptera: Coccinellidae), Staphylinidae adults (Coleoptera), Orius sp. and Xylocoris sp. (Hemiptera: Anthocoridae), Formicidae (Hymenoptera), and Phlaeothripidae (Thysanoptera). The most abundant parasitoids were Hymenoptera of the families Eulophidae, Braconidae (Bracon sp. and Chelonus sp.), Trichogrammatidae [Trichogramma pretiosum (Riley)] and Bethylidae (Goniozus nigrifemur Ashmead), besides Tachinidae (Diptera).

A utilização de perácidos na deslignificação e no branqueamento de polpas celulósicas

Abstract: Peracids are strong oxidant species and their use is being largely studied in the delignification and cellulose pulp bleaching. Some of them has already an industrial application, specially in non-conventional bleaching sequences like ECF (Elemental chlorine free) and TCF (Totally chlorine free). This review presents the main aspects of the structure, properties, preparation and reaction of peracids (peracetic acid, peroxymonosulfuric acid and their mixture) with lignin, specially for peracetic acid. Information about bleaching and delignification of wood pulps with peracids and the factors affecting its efficiency are also presented.

Multivariate analyses of genotype x environment interaction of popcorn

Abstract: The objectives of this work were to evaluate the genotype x environment (GxE) interaction for popcorn and to compare two multivariate analyses methods. Nine popcorn cultivars were sown on four dates one month apart during each of the agricultural years 1998/1999 and 1999/2000. The experiments were carried out using randomized block designs, with four replicates. The cv. Zelia contributed the least to the GxE interaction. The cv. Vicosa performed similarly to cv. Rosa-claro. Optimization of GxE was obtained for cv. CMS 42 for a favorable mega-environment, and for cv. CMS 43 for an unfavorable environment. Multivariate analysis supported the results from the method of Eberhart & Russell. The graphic analysis of the Additive Main effects and Multiplicative Interaction (AMMI) model was simple, allowing conclusions to be made about stability, genotypic performance, genetic divergence between cultivars, and the environments that optimize cultivar performance. The graphic analysis of the Genotype main effects and Genotype x Environment interaction (GGE) method added to AMMI information on environmental stratification, defining mega-environments and the cultivars that optimized performance in those mega-environments. Both methods are adequate to explain the genotype x environment interactions.

Efeito do processamento doméstico sobre o teor de nutrientes e de fatores antinutricionais de diferentes cultivares de feijão comum

Abstract: O feijao comum (Phaseolus vulgaris, L.) e uma fonte rica de nutrientes, porem a presenca de fatores antinutricionais limita seu valor nutricional. Avaliou-se o efeito do processamento domestico no teor de nutrientes e fatores antinutricionais de cinco cultivares de feijao comum: branco (Ouro Branco), negro (Diamante Negro) e marrom rajado (BRS Radiante, Perola e Talisma). Foram utilizadas farinhas de feijoes crus, feijoes cozidos sem maceracao, feijoes cozidos com agua de maceracao e feijoes cozidos sem agua de maceracao, quantificados quanto a composicao centesimal e teores de minerais, taninos e fitatos. Em farinhas de feijoes cozidos com agua de maceracao tambem foi determinada a fibra alimentar total, a soluvel e a insoluvel, e o perfil de aminoacidos. Observou-se que todos os parâmetros quantificados dependeram da cultivar. O processo de cozimento influenciou apenas no teor de taninos e fitatos, provocando a maior reducao de ambos os fatores apos o cozimento sem agua de maceracao. O cozimento tambem provocou um aumento no teor de fibra alimentar insoluvel e reducao de fibra alimentar soluvel em relacao as cultivares cruas. Com base nos escores quimicos corrigidos pela digestibilidade (PDCAAS), a cultivar Perola foi a fonte proteica de mais baixa qualidade e a Talisma foi a de melhor qualidade.