Genetic diversity of Phaeoisariopsis griseola in the State of Minas Gerais, Brazil

Due to the importance of common bean angular leaf spotin the state of Minas Gerais-Brazil and to the greatvariability of the pathogen, Phaeoisariopsisgriseola, monitoring races becomes an important toolfor breeding programs aiming at genetic resistance.The pathogenic variability of 30 isolates of the P. griseola, collected from various locations in thestate of Minas Gerais, was studied using the followingcommon bean differential series (Don Timóteo,Bolón Bayo, Montcalm, G 5686, Amendoin, G 11796,BAT 332, PAN 72, Cornell 49-242, México 54, Florde Mayo and G 2858). The first trifoliate leaf wasinoculated with a 2 × 10⁴ conidia/mL. Plants weremaintained at 20–22 ^°C and 95% relativehumidity for 48 hours. Symptom evaluation wasperformed 15 days after inoculation. Thirteen raceswere identified demonstrating the wide geneticvariability of the pathogen in the state of MinasGerais. Race 63.63 was the most virulent, whereas race63.23 was the most frequent (10 of 30 isolates), beingwidely distributed among the regions studied. Thevirulence phenotype indicated that the races studiedbelonged to the Mesoamerican group, which wasconfirmed when the 30 isolates were compared to Andeanand Mesoamerican standards using RAPD markers.     

Agronomic and molecular characterization of gamma ray induced banana (<Emphasis Type="Italic">Musa</Emphasis> sp.) mutants using a multivariate statistical algorithm

Bananas are tropical fruits grown worldwide playing a key role in market trade and especially used as main food source for low income populations. In Brazil, bananas are mainly consumed in natura, occupying the second largest internal market. Nevertheless, this crop presents low availability of productive commercial varieties with good agronomic characteristics. A strategy undertaken to solve this problem is the development of new cultivars through conventional genetic breeding methods. However, this strategy presents some obstacles such as female sterility and low number of seeds. In order to overcome these shortcomings, use of mutation induction aiming the selection of mutants with desirable agronomic characteristics seems to have great potential for developing new cultivars. The objective of the present work was to evaluate the genetic variability in putative banana ‘Pacovan’ (AAB genome, subgroup Prata Type) mutants submitted to gamma ray irradiation, using a set of agronomical and molecular data (ISSR markers). The distance between the putative ‘Pacovan’ mutants varied from 0.26 to 0.64 with cophenetic correlation coefficient of 0.7669. Four mutants were selected based on best agronomical characteristics and height. This data also shows that there is variability that can be explored after the irradiation of ‘Pacovan’ banana mutants, which can be used in the genetic breeding program of banana aiming to develop short new varieties that also present good agronomic characteristics. This is the first attempt to use combined data in order to evaluate the genetic variability in putative banana mutants.     

Microbiological evaluation of dressing procedures for crocodile carcases in Queensland

SUMMARY Microbiological testing of crocodiles during the dressing procedure has shown that sanitising the skin before skinning reduces the bacterial count on the skin and that dipping crocodile meat in 1.3% acetic acid solution effectively reduces bacterial levels. The total bacterial count on the processed meat sample was comparable with that obtained in the beef, pork and lamb industries. Salmonellae were isolated from 14 of the 72 carcases. Most (65%) of these isolates were in Salmonella subspecies III, formerly classified as Arizona.     

The determination of the age and growth of SE Asian mangrove seedlings from internodal counts

The occurrence of periodic changes in the length of the internodes of the seedlings of SE Asian mangrove species (Rhizophora apiculata, Avicennia alba, and Sonneratia caseolaris) growing in the Pak Phanang estuary (Nakhon Si Thammarat, SE Thailand) was confirmed. The annual nature of these periodic changes was verified through comparisons with the observed average number of internodes produced by plants tagged for one year. The cycles in the sequence of internodal length of the seedlings had an average (± SE) period of 16.0 ± 0.78 internodes for Avicennia alba, 25.0 ± 1.2 internodes for Sonneratia caseolaris, and 8.29 ± 0.40 internodes for Rhizophora apiculata. These values are remarkably close to, and not significantly different (ttest, P > 0.05) from the average (± SE) annual number of internodes of 17.6 ± 0.8 for Avicennia alba, 28.8 ± 2.1 for Sonneratia caseolaris, and 8.03 ± 0.36 for Rhizophora apiculata produced in a year by tagged plants. In addition, the average (± SE) growth of the tagged plants was 0.39 ± 0.018cm day^-1 for Avicennia alba, 0.24 ± 0.015cm day^-1 for Sonneratia caseolaris, and 0.091 ± 0.0036cm day^-1 for Rhizophora apiculata. These estimates were very close to those (0.45 ± 0.06cm day^-1 for Avicennia alba, 0.32 ± 0.01cm day^-1 for Sonneratia caseolaris, and 0.13 ± 0.005cm day^-1 for Rhizophora apiculata) derived as the product of the mean number of internodes produced per day, calculated from the inferred number of internodes produced per year, and the mean length of the internodes of the plants. These findings indicate that the use of regular, annual changes in the length of the internodes of mangrove seedlings can be used reliably to determine their age and to estimate their growth rate.     

Particle nucleation in the tropical boundary layer and its coupling to marine sulfur sources

New particle formation in a tropical marine boundary layer setting was characterized during NASA's Pacific Exploratory Mission-Tropics A program. It represents the clearest demonstration to date of aerosol nucleation and growth being linked to the natural marine sulfur cycle. This conclusion was based on real-time observations of dimethylsulfide, sulfur dioxide, sulfuric acid (gas), hydroxide, ozone, temperature, relative humidity, aerosol size and number distribution, and total aerosol surface area. Classic binary nucleation theory predicts no nucleation under the observed marine boundary layer conditions.     

Tomato chlorosis virus in pepper: prevalence in commercial crops in southeastern Spain and symptomatology under experimental conditions

Tomato chlorosis virus (ToCV), a member of the genus Crinivirus (family Closteroviridae), has been present in Spain since at least 1997, causing annual epidemics of yellowing in protected tomato crops. In 1999, sweet pepper plants exhibiting stunting and symptoms of interveinal yellowing and mild upward curling in the leaves, were found to be infected with ToCV in a greenhouse heavily infested with the whitefly Bemisia tabaci in the province of Almería, southeastern Spain. This study investigated the prevalence of ToCV in tomato and pepper crops in the major growing areas of southeastern Spain (Murcia, Almería and Málaga provinces) over a 3‐year period. In addition, an experimental system was developed for ToCV inoculation using B. tabaci as a vector, which allowed analysis of susceptibility of different pepper cultivars to the virus. The disease syndrome and yield losses induced by ToCV in pepper were also studied under experimental conditions, confirming severe yield reduction in infected plants.     

Potato, an experimental and natural host of the crinivirus Tomato chlorosis virus

Tomato chlorosis virus (ToCV, genus Crinivirus, family Closteroviridae) causes yellowing of tomatoes in many countries worldwide. Symptoms of ToCV infections in tomatoes include inter-veinal yellow chlorotic areas that develop first on lower leaves and then advance towards the upper part of the plant. ToCV is transmitted in nature by the whiteflies Bemisia tabaci, Trialeurodes vaporariorum, and Trialeurodes abutilonea in a semi-persistent manner. In the summer of 2006, a few potato (Solanum tuberosum) volunteer plants heavily infested with the whitefly B. tabaci were found growing within a pepper crop in the province of Málaga, southern Spain. Leaf samples from volunteer plants were tested for the presence of ToCV by molecular hybridization and RT-PCR, and were shown to be infected. Furthermore, potato plants were readily infected by ToCV after experimental transmission using B. tabaci biotype Q as vector. ToCV was also detected in the tubers from infected plants that subsequently produced infected plants. Potato also served as virus source for tomato infection via B. tabaci transmission.     

Geometric approach to evaluate the energy/protein balance in tambaqui (Colossoma macropomum): Can fish ensure nutritional intake targets by postingestion signals?

The aim of this study was to investigate the ability of tambaqui (Colossoma macropomum) to balance the energy (E) and protein (P) ratio by encapsulated diets (without sensory properties). Thirty fish (71.37 ± 2.58 g) were distributed in six 250‐litre tanks. Protein (P), carbohydrate (C) and fat (F) were encapsulated separately to ensure the same sensory properties of each macronutrient. Diets varied in terms of macronutrients to allow the maximal/minimal possibility of ingesting each nutrient following a geometric approach. P, C and F capsules were provided for 40 days (phase 1). After this procedure, fish were subjected to fixed low and poor protein challenges (200 g/kg), and freely to C + F, to evaluate whether they maintained a given intake target (phase 2). As a result, tambaqui showed an intake target at 300 g/kg of crude protein and 16.74 MJ per kg. Give the possibility of freely feeding protein, fish regulated their feed intake and showed a constant E/P ratio pattern (5.024‐5.861 MJ/kg). When protein was restricted and fixed at 200 g/kg, fish maintained similar feed consumption until the end of phase 1, probably to keep a minimal protein amount according to their nutritional requirements.