Summary Brazilian forest‐based industries are supported by more than 5.5 million hectares of Eucalyptus growing under different climatic conditions with different degrees of favourability for rust Puccinia psidii , including both traditional and expanding areas, where such disease is of major concern for the industry, foresters and scientists. The main objective of this study was to define favourable climatic zones for Eucalyptus rust in Brazil with the following aims: (i) to develop a spatial method for estimating the mean night‐time temperature ( T ng ); (ii) to assess and validate a Eucalyptus rust model; and (iii) to map Eucalyptus rust favourability zones in Brazil based on the proposed model. A straightforward method, based only on latitude, day of the year, maximum and minimum air temperatures, was developed to estimate T ng , which is a key variable for a proper application of Ruiz rust model. Based on 37 field experiments with natural rust occurrence, it was observed that climatic conditions are determining factors for disease severity. Significant correlations between disease severity observed in the field and climatic conditions were found: a negative correlation with temperature ( r = .50, p < .01) and a positive correlation with relative humidity ( r = .89, p < .0001). A significant correlation ( r = .81, p < .0001) between the normalized infection index, produced from Ruiz model, and the average rust score was also observed. Once the model was validated under field conditions, it was applied using historical average data of air temperature and leaf wetness duration to obtain monthly Eucalyptus rust favourability maps for the whole country. These final maps show that favourable climatic zones for Eucalyptus rust are extremely dynamic, with high temporal and spatial variability in Brazil and that climatic conditions should be considered for expansion of Eucalyptus to new areas, in breeding programmes, and for defining the most suitable seasons for forest establishment in each climate of the country. These results provide forestry managers with practical tools to reduce uncertainty about the expected severity of Eucalyptus rust in Brazil.
The epidemiology of the Neotropical rust caused by Puccinia psidii in the Indian Myrtaceae Syzygium jambos (rose apple) was investigated in central Brazil. Disease severities recorded during a 12‐month period were fitted by a Fourier curve with three cyclic components or harmonics. The first, second and third harmonics accounted for 49·6, 25·9, and 1·5% of total disease measured, respectively. A highly significant linear correlation was observed between the first harmonic and the accumulated number of days having at least 6 h wetness, or a minimum of 90% relative humidity, combined with temperatures that ranged from 18 to 20°C. No significant correlation was observed between the second and third harmonics and the weather variables evaluated. Rose apple trees showed a flush of growth with new susceptible host tissue during the evaluation period, with two major outbreaks of rust of variable intensity. Host growth was fitted by a Fourier curve with two significant harmonics. The first and second harmonics accounted for 37·5 and 22·1% of total host growth measured, respectively. A highly significant negative linear correlation was observed between the first harmonic and daily maximum and minimum temperatures, rainfall, and duration of the light period. Inoculum availability was not a limiting factor for disease progress since urediniospores were present during most of the period studied. A major peak in numbers of rust spores followed the main peak of disease severity. Thus, rust epidemics on rose apple in central Brazil were shown to depend on the duration of leaf wetness in the dark, and also on night‐time temperatures during that same wetness period. This study is the first example of a periodical analysis of an epidemic in a perennial crop.
La forma en que los individuos son seleccionados en una prueba de progenie es fundamental en la conservación y mejoramiento genético. Una prueba de progenie con un total de 26 progenies de Eucalyptus urophylla, proveniente de Río Claro-SP, con selección en Anhembi-SP, se instaló en Selvíria-MS el 03/10/1991, con un espaciamiento de 3,0 x 3,0 m, seis plantas por parcela lineales y cuatro repeticiones, en bloques al azar. . El suelo es un Latosol Rojo distrófico, la precipitación anual del lugar es de 1.300 mm y la temperatura media anual es de 25º C. A los 19 años de edad se evaluó lo carácter DAP (diametro a la altura del pecho) por el procedimiento REML/BLUP, y presentó una media de 27,4 cm.. Con base en este carácter, se utilizaron dos estrategias de selección: La primera consideró la selección de los primeros 104 mejores individuos independientemente de la progenie a la cual pertenecían, seleccionados por su valor genético dado por BLUP. Esta selección proporciona un tamaño efectivo de 33 y una ganancia en la selección de 3,1%. En la segunda estrategia se optó por la selección solo dentro de las progenies; los cuatro mejores individuos de cada progenie, lo que proporciona un tamaño efectivo de 59 y una ganancia de 1,8%
Abstract One of the determinant factors in the success of breeding programs that aim to select genotypes for different geographical regions is understanding the interaction between genotypes and environments (GxE). The objectives of this study were to evaluate GxE interaction, stability, and adaptability, and determine the need for environmental stratification of open pollinated progenies of Eucalyptus urophylla. Five progeny tests were established in study areas with different environmental conditions in southeast and mid-west Brazil. We used a complete randomized block experimental design with 138 to 167 progenies, and variations in the numbers of replicates and plants per plot. The trait measured was diameter at breast height (DBH) at two years of age and the AMMI method was used to determine patterns of GxE interaction. Significant effects were detected for genotypes, environments, and for GxE interaction. The effect of environment was responsible for the greatest proportion of the phenotypic variation, followed by the effect of genotypes and GxE interaction. Some progenies with greater productivity and stability were identified, although stability is not associated with productivity. The stratification of the selection in three specific environments is necessary due to the occurrence of a complex GxE interaction.
Orchids are ornamental plants that stand out by their colors, types, shapes, size, beauty. Additionally, some species have aromas. This diversity of orchids makes it be greatly appreciated as potted plants, landscaping, with high commercial value. The aim of this study was to evaluate the development of orchids at different levels of fertilization by reusing nutrients added to the culture medium for cultivation in vitro is also analyzing the different times of acclimatization. The micropropagated orchids removed from the growth chamber, were transported to greenhouse composing the different treatments for acclimatization (0, 10, 20, 30, 40 and 50 days). To be transplanted were placed in pine bark substrate and Sphagnum being placed in trays. After 30 days the seedlings were transplanted to styrofoam trays was initiated plant fertilization weekly with different formulated by administering 5 ml each (1 humic acid, 2nd potassium nitrate (KNO 3 ), 3rd humic acid + Nitrate potassium (KNO 3 ), 4th calcium chloride (CaCl 2 ), 5 ° control). Six months after withdrawal of the growth room the plants was carried out the evaluation of the experiment where the plant survival was evaluated by the number of shoots, number of leaves, the length of the largest leaf and root presence. The experimental design was completely randomized in a factorial 6x5, with the time of acclimatization (0, 10, 20, 30, 40 and 50 days) the first factor and the second, the type of fertilizer used (4 formulated and the witness) with 8 replicates per treatment. The data were submitted to deviance analysis in the software R. In this study, the need to fertilize with nutrient rich formulations for orchids in the acclimatization phase was contacted and that these should remain for a few days inside the jars in a greenhouse environment.
