Characterization of the resistance of tomato accessions from the bgh-ufv to the geminivírus tomato yellow spot virus

The viruses transmitted by whiteflies are among those causing relevant losses in tomato cultivation. Among the measures to control these agents, introducing genes for resistance constitutes the main control measure, together with vector control. The objective of this work was to screen for sources of natural resistance to Tomato yellow spot virus (ToYSV) in S. lycopersicum germplasm from the Banco de Germoplasma de Hortaliças (BGH) of the Universidade Federal de Viçosa (UFV), Minas Gerais, Brazil. The 99 accessions and two susceptible controls were inoculated using biolistics. Inoculated plants were grown under greenhouse conditions. The percentage of plants displaying virus symptoms was evaluated at 10, 20 and 30 days after inoculation (DAI). Virus presence or absence in the inoculated plants was confirmed by hybridization with probes labeled with á-[32P]-dCTP, for each evaluation date. Inoculated plants produced typical disease symptoms showing different behavior on the genotypes in relation to ToYSV. Some of the evaluated genotypes showed higher virus tolerance compared to two susceptible controls, in particular the accessions BGH-2039V and BGH-2041 which showed no symptoms and no viral DNA accumulation in 80% of the inoculated plants at 30 DAI. The results suggest that the selected tomato accesses are good sources of resistance to new tomato cultivars tolerant to ToYSV.Os vírus transmitidos por moscas brancas estão entre aqueles que causam perdas relevantes na cultura do tomate. Entre as medidas para o controle desses agentes, a introdução de genes de resistência constitui a principal medida de controle, juntamente com o controle de vetores. O objetivo deste trabalho foi procurar fontes de resistência natural ao Tomato yellow spot virus (ToYSV) em germoplasma de S. lycopersicum do Banco de Germoplasma de Hortaliças (BGH) da Universidade Federal de Viçosa (UFV), Minas Gerais, Brasil. Noventa e nove subamostras e dois controles suscetíveis foram inoculados usando biobalística. As plantas inoculadas foram mantidas em casa de vegetação. A porcentagem de plantas exibindo sintomas do vírus foi avaliada aos 10, 20 e 30 dias após a inoculação (DAI). A presença ou ausência do vírus nas plantas inoculadas foi confirmada por hibridização com sondas marcadas com á-[32P]-dCTP, para cada data de avaliação. Plantas inoculadas produziram sintomas típicos da doença mostrando diferentes comportamentos dos genótipos em relação ao ToYSV. Alguns dos genótipos avaliados apresentaram maior tolerância ao vírus em relação aos dois controles suscetíveis, em particular as subamostras BGH-2039V e BGH-2041, que não apresentaram sintomas e no tinham acúmulo de DNA viral em 80% das plantas inoculadas aos 30 DAI. Os resultados sugerem que as subamostras de tomate selecionadas são boas fontes de resistência para novas cultivares de tomateiro tolerantes ao ToYSV

MORFOLOGIA POLÍNICA DE Hyptis JACQ. (LAMIACEAE) NO ESTADO DO RIO GRANDE DO SUL, BRASIL

São descritos e ilustrados, a morfologia polínica de 13 espécies do gênero Hyptis (Lamiaceae), ocorrentesno Estado do Rio Grande do Sul, Brasil. Foram estudadas, em nível de microscopia óptica a forma, o tipo deabertura, a ornamentação e as medidas do material polínico acetolisado, proveniente de exsicatas de herbário

Evaluation of models for prediction of the energy value of diets for growing cattle from the chemical composition of feeds

The objective of this study was to estimate and evaluate the contents of apparently digestible fractions of crude protein, ether extract and non-fibrous carbohydrates, the digestible fraction of the neutral detergent fiber and the content of total digestible nutrients (TDN) from the chemical composition of feeds in growing cattle fed different diets. Fourteen F1 Red Angus × Nellore young bulls with average age and weight of 12 months and 287±36 kg were used. Animals were fed elephant grass silage, corn silage or signal grass hay, with or without supplementation of 200 g concentrate per kg of the total diet. The experiment consisted of two 13-days periods, in which the concentrate supplementation was crossed over animals. The values of digestible fractions and the TDN content observed were obtained based on total collection of feces. Several sub-models applied to the different digestible fractions were assessed and discussed. Estimates of the TDN content in the diet were produced from the combination of sub-models applied to the individual digestible fractions. The TDN content was more efficiently predicted from the sub-models proposed by Detmann et al. (2010) when biological procedures for the estimation of the undegradable fraction of the protein and the potentially degradable fraction of the neutral detergent fiber were considered

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved