ABSTRACT. The spread of the epiphytic population of Xanthomonas campestris pv. vesicatoria and the disease it causes, bacterial leaf spot, were studied in field plots of pepper near Gainesville, Florida. In the summer of 1989, the epiphytic population of X. campestris pv. vesicatoria was dispersed to the west-northwest from point sources of diseased plants. Winds from the southeast during rainstorms were essential for the spread of bacteria in the field. In the autumn of 1989, a focus of bacterial leaf spot developed naturally near the centre of the experimental plot.

ABSTRACT. Visible (VIS) and near infrared (NIR) reflectance spectroscopy combined with multivariate data analysis were explored to predict fibre diameter in both clean and greasy Merino wool samples. Fifty clean and 400 greasy wool samples were analysed. Samples were scanned in a large cuvette using a NIRSystems 6500 monochromator instrument by reflectance in the VIS and NIR regions (400 to 2500 nm). Partial least square (PLS) regression was used to develop a number of calibration models between the spectral and reference data.

ABSTRACT. Estimators for standard errors of heritability for two typical and complex forage breeding models are illustrated with estimates of variance and covariance components from least-squares and restricted maximum likelihood methods. The first experiment (Model 1) is a factorial design (two grazing management factors) with two layers of split plots (populations and grazing periods) and with plants within populations nested beneath the first split. The second model is for a sites pooling of randomized complete block experiments, with plants nested inside plots and with a split in time.

ABSTRACT. This study reports the use of visible (vis) and near infrared (NIR) spectroscopy as a tool to classify honey samples from Uruguay, according to their floral origin. Classification models were developed using principal component analysis, discriminant partial least squares (DPLS) regression and linear discriminant analysis (LDA). Honey samples (n = 50) from two floral origins, namely Eucalyptus spp. and pasture, were split randomly into even calibration (n = 25) and validation sets (n = 25).

ABSTRACT. Livestock production plays an important role in guaranteeing food security worldwide and has an important contribution to the economy of many countries. Precision livestock production (PLP), or the manipulation of livestock activity taking into account the different components of agroecosystems −pastures, cattle and pasture-cattle interactions−, has acquired growing importance in recent years to optimize productivity. Regarding the pasture component, multi-species pasture mixtures are commonly used worldwide to increase primary productivity and thereby secondary productivity.

ABSTRACT. Livestock production plays an important role in guaranteeing food security worldwide and has an important contribution to the economy of many countries. Precision livestock production (PLP), or the manipulation of livestock activity taking into account the different components of agroecosystems −pastures, cattle and pasture-cattle interactions−, has acquired growing importance in recent years to optimize productivity. Regarding the pasture component, multi-species pasture mixtures are commonly used worldwide to increase primary productivity and thereby secondary productivity.

ABSTRACT. Successful crop management requires understanding relationships between site characteristics and crop yield. We studied intercorrelations among soil and crop properties using factor analysis (FA) and principal components analysis (PCA), and their relationships with soybean [Glycine max (L.) Merr.] within-field yield variability.

ABSTACT. Heat stress represents a major environmental factor that negatively affects the health and performance of dairy cows, causing huge economic losses to the dairy industry. Identifying and selecting animals that are thermotolerant is an attractive alternative for reducing the negative effects of heat stress on dairy cattle performance.

ABSTRACT. The aim of this work was to describe the epidemiological, clinical and pathological aspects of spontaneous poisoning by Merremia macrocalyx in cattle in the Pernambuco state, northeastern Brazil, and to experimentally replicate the poisoning by this plant. To determine the occurrence of poisonings, 30 farms were visited in six municipalities at the Forest Zone of Pernambuco. The plant was found in nine farms, in which history of plant poisoning in cattle, and occasionally in sheep were also reported. Three outbreaks of spontaneous poisonings in cattle were studied.

ABSTRACT. The aim of this research was to obtain information on the behaviour of the species under cultivation. Seeds were sown on December 18, 1992, in a field seedbed under plastic cover. Plants were taken to the field when 15 cm high (February 18, 1993). Three lines with 47 plants each were managed independently. Plants from Line 1 were harvested on August 4, Line 2 on August 19, and Line 3 on September 13, 1993. Mean fresh weight per plant for each line was 261, 207 and 337 g, and 88, 78 and 105 g, respectively, expressed in dry weight.