Caused by Sclerotinia sclerotiorum, white mold is an important seed-transmitted disease of soybean (Glycine max). Incubation-based methods available for the detection and quantification of seed-borne inoculum such as the blotter test, paper roll and Neon-S assay are time-consuming, laborious, and not always sensitive. In this study, we developed and evaluated a molecular assay for the detection of S. sclerotiorum in soybean seeds using a species-specific PCR (polymerase chain reaction) primer set and seed soaking (without DNA extraction) for up to 72 h. The PCR products were amplified in all the samples infected with the pathogen, but not in the other samples of plant material or the other seed-borne fungi DNA. The minimum amount of DNA detected was 10 pg, or one artificially infested seed in a 400-seed sample (0.25 % fungal incidence) and one naturally infected seed in a 300-seed sample (0.33 % incidence). The PCR-based assay was rapid (< 9 h), did not require DNA extraction and was very sensitive.

Objetivou-se neste trabalho estudar a regeneração in vitro da planta daninha Euphorbia heterophylla a partir de explantes hipocotiledonares, cotiledonares e radiculares com diferentes concentrações do hormônio 2iP, combinado ou não com auxina e cinetina adicionado ao meio MS/2. Foram avaliados os números de explantes com gema, número de gemas por explante, número de plântulas enraizadas e aclimatadas. Obteve-se em média duas gemas por explante hipocotiledonar em 50% desses, a partir de organogênese direta com o uso de 0,5 mg.L-1 de 2iP. Não houve regeneração a partir dos explantes cotiledonares e radiculares. A cultura racinar desenvolveu-se em todos os tratamentos contendo ou não auxina. Esses resultados poderão auxiliar em futuros testes fisiológicos de resistência dessa planta a herbicidas.

This work aimed to study the in vitro regeneration of the weed Euphorbia heterophylla from hypocotyls, cotyledon and root explants grown under different concentrations of the hormone 2iP, combined or not with auxin added to MS/2 medium. The parameters analyzed were the number of explants with shoot, number of shoot for explants, number of rooted and acclimatized plants. The results showed an average of two shoot for hypocotyls explants, in 50% of these, from direct organogenesis with the use of 0.5 mg. L-1 of 2iP. No regeneration from the cotyledon and root explants was verified. The root culture developed in all treatments with or without auxin. These results will be able to assist in future physiological tests of resistance of this plant of herbicides.

Objetivou-se avaliar o efeito de aminoethoxivinilglicina (AVG), aplicado na pós-colheita, no amadurecimento de frutos de caqui (Diospyros kaki L.) cv. Fuyu, armazenados à temperatura de 0 ± 2 ºC. Os frutos foram imersos durante dois minutos em solução de AVG, na concentração de 0; 415; 830 e 1.200 g ha-1 e dissolvidos em água destilada e adição de espalhante adesivo (óleo vegetal) a 0,02% (v/v), secos à temperatura ambiente no barracão e armazenados em câmara fria a 0 ± 2 ºC e 95±2 % UR, e avaliados aos 32 e 52 dias com relação à firmeza, sólidos solúveis, pH da polpa, acidez titulável e injúria por frio. O AVG mostrou-se promissor no uso pós-colheita em caqui, onde os frutos tratados conservaram índices de firmeza linear em função da dose e teores de AT, SS e pH aceitáveis para o 'Fuyu'. Porém os frutos apresentaram translucidez, característica de injúria por frio, indicando a necessidade de novos estudos para se compreender a fisiologia pós-colheita deste fruto.

An experiment was carried out to analyze the effect of the application of Aminoethoxyvinylglycine (AVG) in post harvest application in persimmon fruits (Diospyros kaki L.) cv. Fuyu stored at a temperature of 0 ± 2ºC. The fruits were immersed for two minutes into an AVG solution at a concentration of 0; 415; 830; 1200 g ha-1 and dissolved in distillated water. Then it was added adhesive spreader (vegetable oil) 0.02% (v/v), dried at room temperature and stored at 0 ± 2 ºC and 95±2 % humidity. The treatments were evaluated on the 32nd and 52nd days to check the firmness, soluble solids, pH of the pulp, tritable acidity and chilling injury. The AVG may be promising in post harvest use with persimmon fruits, where treated fruits preserved linear levels of firmness in function of the doses and TA, SS and pH levels are acceptable for cv. Fuyu. However, fruits showed translucency, which are characteristics of chilling injury, indicating that new studies are necessary to understand the post harvest physiology of this fruit.