Fernando Cezar Juliatti

Resistência de genótipos de soja à Phakopsora pachyrhizi

The aim of the present study, was to quantify the resistance in fifty soybean genotipes of the cerrado region to the rust caused by Phakopsora pachyrhizi .One experiment in greenhouse were conducted in Uberlândia , MG from January to July 2004. Average latent period, number of pustules per cm2 and disease severity were evaluated. Azevedo, L.A.S.; Juliatti, F.C.; Barreto, M.. Resistance of Soybean Genotipes of the Cerrado Region to Rust Caused by Phakopsora pachyrhizi. Summa phytopathologica, v.33, n.3, p.252-257, 2007. RESUMO O presente trabalho teve como objetivo, quantificar a resistencia a Phakopsora pachyrhizi em 50 genotipos de soja na regiao do cerrado. Foi conduzido em Uberlândia, MG , um experimento em casa de vegetacao, durante o periodo de janeiro a julho de 2004. Foram avaliados os seguintes parâmetros de resistencia: periodo latente medio, numero medio de pustulas por cm 2 e severidade da ferrugem. Com base nesses parâmetros, calculou-se a area abaixo da curva de progresso da doenca. Apos, analise de variância e teste Azevedo, L.A.S.; Juliatti, F.C.; Barreto, M.. Resistencia de Genotipos de Soja a Phakopsora pachyrhizi. Summa phytopathologica, v.33, n.3, p.252-257, 2007.

Interação entre resistência genética p arcial e fungicidas no controle da ferrugem asiática da soja

The objective of this work was to analyze the interaction between cultivars and fungicides for soybean Asian rust control, in two sowing times. The experiment was carried out in field conditions, from September 2005 to May 2006. The following traits were analyzed: incidence, severity (percentage of infected leaf area and visual grading of the plot), number of pustules per square centimeter, weight of one thousand seeds and yield. The area under the disease progress curve (AUDPC) was calculated for disease data. Significant effects were observed for cultivars, fungicides, and the interaction between these factors for AUDPC, as well as for weight of one thousand seeds and yield. The cultivars IAC-100, Potenza and UFUS-Impacta, in both sowing times, presented partial resistance to Asian rust, which was highlighted by the low values of AUDPC. The triazole group fungicide cyproconazole and its mixture with the strobilurin group fungicide azoxystrobin were effective on Asian rust control.

Avaliação de diferentes pontas e volumes de pulverização na aplicação de fungicida na cultura do milho

ABSTRACT Application technology is a major factor for the success of cropsbecause it determines the correct application of pesticides. Theexperiment was carried out in Mandaguari Farm (IndianopolisMunicipality, Minas Gerais State, Brazil). The experimental designwas in randomized blocks, with 13 treatments and 4 replicates.Treatments consisted of 4 nozzles (TT, AD / D, ADIA / D, emptycone) and 3 spray mix volumes (100, 150 and 200 L ha -1 ), besidescontrol. The aim of this work was to study nozzles and to set thesuitable volume of fungicide application for the rational diseasemanagement in maize crop. Disease severity, drops cm -2 , green areapercentage, 1000-grain weight, and yield were evaluated; an economic Juliatti, F.C.; Nascimento, C.; Rezende, A.A.. Evaluation of different nozzles and volumes in fungicide application on maIze crop. SummaPhytopathologica, v.36, n.3, p.216-221, 2010. Keywords: Zea mays , Chemical control, Application technology.

Adaptability and stability of soybean advanced lines of semi early cycle for rust resistance.

This research work was carried out to verify the adaptability and phenotypic stability of soybean inbred lines of semi early cycle, using rust severity as the selection trait for partial resistance. The strains were evaluated during the growing seasons of 2007/08 and 2008/09, in the locations of Uberlândia and Uberaba, MG, Campo Alegre de Goias and Senador Canedo, GO, using a randomized complete block design with three replications. Rust severity was evaluated by visual assessment of the leaflets at the medial third of five plants in each plot. By using disease severity, it was estimated: the mean absolute rate of disease progress (r), the area under the disease progress curve (AUDPC) and the partial resistance factor (PRF). Adaptability and stability of the strains were estimated by the methods proposed by Eberhart and Russell, as well as by the AMMI method. It was found that the strains which were the most resistant to rust, in general, also showed the best adaptability and stability.

Strategies of Chemical Protection for Controlling Soybean Rust

Asian soybean rust (Phakopsora pachyrhizi) is an aggressive and destructive disease that undermines the current 34 million hectares of soybean production system in Brazil. The disease is present throughout the entire cultivated area. The disease control has required a combination of several practices in order to avoid losses. In the last 15 harvests, the application of fungicides has been shown as an effective alternative for the producer in the control of this aggressive disease. Since the first fungicides emergency recommended for the 2002/03 season (azoxystrobin, difenoconazole, fluconazole, pyraclostrobin + epox‐ iconazole, and tebuconazole), a large number of new formulations were added to the arsenal to control rust. There are today recorded in MAPA (Ministry of Agriculture and Supply) about 45 active ingredients (alone or in combination are about 120), trademarks, and formulations for the rational use against rust. Among fungicides, there are differ‐ ences in efficacy, residual period, metabolic stability, and translocation rate, requiring care from the producer and technical assistance in the choice of the product to be used in each situation. In this review, the chemical control of rust is analyzed in Brazil from 2001/02 to 2013/14; its economic importance, strategic variables for the rational fungicides practice, factors that complicate the chemical control and the risk of resistance to the main chemical groups.

Genetic control of partial resistance to Asian soybean rust

The genetic control of rust resistance was studied using the Caiaponia x IAC-100 and Luziânia x Potenza crosses. The F 2 and F 3 generations were evaluated. Rust severity was quantified through visual assessment of the middle third of three leaflets per plant and performed by three different evaluators; the average score was calculated foreach individual plant. From these data, we estimated the mean and variance of the genetic components by employing the weighted least squares method. The estimated number of genes and broad- and narrow-sense heritabilities were also obtained. It was concluded that rust resistance is a characteristic controlled by 2 to 23 genes that are predominantly dominant. The estimate of narrow-sense heritability was greater than 70% for the Caiaponia x IAC-100 cross, and the wide-sense heritability was greater than 60% for the Luziânia x Potenza cross; thus, it is possible to successfully select resistant individuals in early generations.

Development of Brazilian Soybean Cultivars Well Adapted to Cerrado and Rust-Tolerant

The major diseases limiting soybean growth and yield must be either controlled or mitigated. Among these, soybean rust is the most harmful; in addition, Phakopsora pachyrhizi populations less susceptible to both IDM and IQe fungicides were observed. Therefore, this invention aimed at developing a new soybean cultivar rust resistant and highly productive. Generations were advanced by single seed descent method on the Capim Branco farm, Federal University of Uberlândia. Value for Cultivation and Use were carried out during a 3-year period (2010/13) in several locations, and Distinctness, Uniformity and Stability experiments for a 2-year period (2011/13) on the Capim Branco farm. Hence, we developed the novel soybean cultivar designated UFUS 7415. UFUS 7415 has shown high contents of oil (20%) and protein (40%), and high yield potential (4.300 kg ha-1) even in environments with Asian rust.

Evaluation of the gelatin technique for the preservation of phytopathogenic fungi

The preservation methods for fungi have great importance in ex situ collections, representing important biological heritage, useful for mycologists and plant pathologists in several scientific works. However, there is a lack of studies for a suiTable and efficient preservation method for the different groups of fungi. Although, the most appropriate is the one that maintain, even after long periods, the original characteristics of culture: viability, sporulation and pathogenicity, excluding mutations and undesirable contamination. The choice will depend of the laboratory infrastructure, microorganism, objectives, preferences and knowledge of the researcher. We conducted this study inside the Laboratory of Mycology and Plant Protection (LAMIP) in UFU (Universidade Federal de Uberlândia), localized in Uberlândia (MG), Brazil. The objective was to evaluate the gelatin preservation method (17 cultures), never used before for phytopathogenic fungi. Other classical methods were concomitantly evaluated, such as sterile soil (68 cultures), resistant structures (Sclerotinia sclerotiorum) in 4°C (10 strains) and mineral oil (31 cultures). We examined the time for maintaining the viability, sporulation and colonization in host tissues preserved in different dates. The gelatin method remained viability in 10 cultures; this method is suiTable for preservation of the genera and species: Colletotrichum spp., Septoria spp., Fusarium spp., F. moniliforme var. subglutinans, Macrophomina spp., Phomopsis spp. and Verticillium spp. The viability remained in 38 strains of sterile soil, three of mineral oil, and one strain of sclerotia reached a maximum preservation time in 4°C of four years.

Genetic control of partial resistance to Asian soybean rust doi: 10.4025/actasciagron.v36i1.16919

The genetic control of rust resistance was studied using the Caiaponia x IAC-100 and Luziânia x Potenza crosses. The F 2 and F 3 generations were evaluated. Rust severity was quantified through visual assessment of the middle third of three leaflets per plant and performed by three different evaluators; the average score was calculated foreach individual plant. From these data, we estimated the mean and variance of the genetic components by employing the weighted least squares method. The estimated number of genes and broad- and narrow-sense heritabilities were also obtained. It was concluded that rust resistance is a characteristic controlled by 2 to 23 genes that are predominantly dominant. The estimate of narrow-sense heritability was greater than 70% for the Caiaponia x IAC-100 cross, and the wide-sense heritability was greater than 60% for the Luziânia x Potenza cross; thus, it is possible to successfully select resistant individuals in early generations.

Controle genético da resistência parcial à ferrugem asiática da soja

The genetic control of rust resistance was studied using the Caiaponia x IAC-100 and Luziânia x Potenza crosses. The F 2 and F 3 generations were evaluated. Rust severity was quantified through visual assessment of the middle third of three leaflets per plant and performed by three different evaluators; the average score was calculated foreach individual plant. From these data, we estimated the mean and variance of the genetic components by employing the weighted least squares method. The estimated number of genes and broad- and narrow-sense heritabilities were also obtained. It was concluded that rust resistance is a characteristic controlled by 2 to 23 genes that are predominantly dominant. The estimate of narrow-sense heritability was greater than 70% for the Caiaponia x IAC-100 cross, and the wide-sense heritability was greater than 60% for the Luziânia x Potenza cross; thus, it is possible to successfully select resistant individuals in early generations.