Alexei Campos Dianese

Wheat blast disease, caused by Magnaporthe oryzae pathotype Triticum, was observed in countries of South America and recently in Asia. The spike infection is the most destructive form of the disease due to high reductions in yield and grain quality. To date, nine resistance genes and one hidden resistance gene to blast have been identified in wheat. An association between wheat resistance to blast and the presence of a chromosomal segment (2NS) from Triticum ventricosum was also found. In Brazil, where the disease is endemic, only two cultivars are described as blast resistant. Many aspects of the wheat–M. oryzae Triticum interaction remain to be elucidated. This chapter discusses the genetic and molecular basis of the wheat–M. oryzae Triticum interaction. Phenotyping and grain production data from genotypes contrasting with disease response are presented. A doubled-haploid wheat population was also phenotyped. The parents of the population were submitted to an RNA-seq strategy to examine and compare the overall gene expression levels in spikes when submitted or not to inoculation with M. oryzae Triticum. The molecular functions most representative in gene ontology terms were observed and genes potentially involved in the innate immune mechanisms of the resistant genotype against the blast pathogen were identified.

Brazil is the world's largest producer of passion fruit, a perishable fruit with reduced post-harvest shelf life, which limits its commercialization. For sweet passion fruit, Passiflora alata, there is little information about its postharvest conservation and shelf life under different storage conditions. Thus, the objective of the present study was to determine the post-harvest conservation of P. alata fruits packed on styrofoam trays rapped with 10 μm PVC film and HDPE 30 μm thick, coated with 18% carnauba wax and without any packaging; stored under ambient conditions (25 °C and 70% relative humidity) and refrigerated (10 °C and 90% relative humidity) for 14 days. The best results were obtained with P. alata fruits packaged on styrofoam trays rapped with 10 μm PVC flexible film and kept under refrigeration in a cold room at a temperature of 10 °C and relative humidity between 85% and 90% for a period of 10 to 14 days. Fruits of P. alata , for commercialization “in natura”, kept under ambient conditions, should not be packaged and have a shelf life of up to seven days.

This study aimed to monitor the population fluctuation of Cophes notaticeps (Marshall) (Coleoptera: Curculionidae) in a jatropha (Jatropha curcas L.) plantation in the Federal District, Brazil, through the use of a new trap, combined with different attractive lures and trap colors. The study was conducted at Embrapa Cerrados (Planaltina/DF) in a field trial with 720 plants. The new trap, named CPAC16, was made with PVC pipes (100 mm in diameter) of about 40 cm in length, with a window (8 × 10 cm²) in its center to enable insect access. A lure compartment was fixed on the inside of the trap`s top, and a pot, containing water and detergent, was placed at its bottom to collect the insects. The traps were painted in red, yellow, blue and green. Molasses, ethanol and pineapple were used as attractive lures. The traps were in the field trial area between May 2013 and April 2014 and the insects were collected weekly. The incidence of plants presenting damage caused by C. notaticeps was evaluated in the beginning and at the end of the study. The CPAC16 trap proved efficient in monitoring C. notaticeps. About 3494 of C. notaticeps adults were collected during the study. There were no significant differences among traps painted with different colors. The most attractive lure was molasses collecting 75.2% (n = 2627) of the specimens. Although the population peak occurred in December (n = 1162), C. notaticeps were collected throughout the year. The incidence of plants attacked by C. notaticeps ranged from 66.4% (start) to 100% (end).

Soybean (Glycine max L.) is the most widely cultivated crop in the world and an important commodity. Besides its main role in human nutrition, this grain is also used in animal feed and production of biofuels, among other purposes. Due to these factors, soybean became important in the global economy and is the most exported agricultural product from Brazil. Fungal diseases are among the limiting factors on soybean production; sudden death syndrome, caused by Fusarium spp., has been responsible for severe losses on this crop in Brazil. Four species of Fusarium can be considered causal pathogens: F. brasiliense, F. crassistipitatum, F. tucumaniae, and F. virguliforme. The Fusarium spp. isolates characterized in this work were collected in different soybean-producing regions in Brazil. The genetic variability of these isolates was determined through the random amplified polymorphic DNA (RAPD) technique. Disease severity was evaluated on moderately resistant and susceptible soybean cultivars in greenhouse trials. RAPD analysis demonstrated a great genetic diversity among the isolates and a clear tendency to split into two main species groups, F. tucumaniae and F. brasiliense, both prevalent in Brazil. The disease severity experiments, in which soybean plants were artificially inoculated, have shown that all isolates caused significant damage to the seedling root system. In fact, the genetic diversity of isolates does not correlate with disease severity, and also does not correlate with geographic distribution.