Vilmar Antônio Ragagnin

Mapeamento de genes de resistência do feijoeiro à ferrugem, antracnose e mancha-angular usando marcadores RAPD

Molecular markers were used to study the organization of rust, anthracnose and angular leaf spot resistance genes in common bean (Phaseolus vulgaris) Ouro Negro cultivar. A segregant population of 154 recombinant inbred lines (RIL´s) from the crossing between Ouro Negro and Ruda cultivars was inoculated under controlled conditions with seven races of Uromyces appendiculatus, three of Colletotrichum lindemuthianum and four of Phaeoisariopsis griseola. DNA samples of each RIL were amplified by polymerase chain reaction using 70 decamer primers. Segregation analysis of rust, anthracnose and angular leaf spot resistance suggested specific resistance inheritance to each physiologic race. Genetic linkage analysis revealed the grouping of different rust and anthracnose resistance genes in the same linkage group. Angular leaf spot resistance genes also were mapped together, but in another linkage group. The utility of RAPD markers linked to common bean resistance genes, previously identified in the literature, was restricted. Only five out of 38 molecular markers tested were validated on the RIL´s population as linked to rust and anthracnose resistance genes. Three new molecular markers (OBA16669 and OAB16583 to 10.4 cM in coupling and OAD93210 to 13.9 cM in repulsion) were identified that are linked to to the angular leaf spot resistance gene block in Ouro Negro cultivar.

Resistência de cultivares de feijoeiro-comum à ferrugem e à mancha-angular em condições de casa de vegetação

Seventeen common bean cultivars recommended for Minas Gerais state, Brazil, were inoculated with five pathotypes (6, 7, 9, 10 and 12) of Uromyces appendiculatus and five pathotypes (63.55, 31.23, 63.39, 31.55 and 63.23) of Phaeoisariopsis griseola. Five experiments were carried out for each pathogen. For rust, infection frequency (IF) and average pustule size (APS) were estimated. Angular leaf spot symptoms were evaluated using a 1 to 9 grading scale. The majority of the cultivars were susceptible to at least three pathotypes of U. appendiculatus. The most susceptible cultivars to rust were Roxo 90 and Meia Noite, and the most resistant was Ouro Negro, which was immune to all pathotypes tested. Roxo 90, Carioca MG, Perola, Carioca 1030 and Apore, which are extensively planted in Minas Gerais State, were widely susceptible to angular leaf spot. Cultivars Ouro Negro and EMGOPA 201-Ouro harbor resistance genes to different pathotypes of P. griseola and, the combination of these genes in a new cultivar would result in resistance to all tested pathotypes.

Identification of Races of Selected Isolates of Uromyces appendiculatus from Minas Gerais (Brazil) Based on the new international classification system

ABSTRACT Twelve single-pustule isolates of Uromyces appendiculatus, the etiological agent of common bean rust, were collected in the state of Minas Gerais, Brazil, and classified according to the new international differential series and the binary nomenclature system proposed during the 3 rd Bean Rust Workshop. These isolates have been used to select rust-resistant genotypes in a bean breeding program conducted by our group. The twelve isolates were classified into seven different physiological races: 21-3, 29-3, 53-3, 53-19, 61-3, 63-3 and 63-19. Races 61-3 and 63-3 were the most frequent in the area. They were represented by five and two isolates, respectively. The other races were represented by just one isolate. This is the first time the new international classification procedure has been used for U. appendiculatus physiological races in Brazil. The general adoption of this system will facilitate information exchange, allowing the cooperative use of the results obtained by different research groups throughout the world. The differential cultivars Mexico 309, Mexico 235 and PI 181996 showed resistance to all of the isolates that were characterized. It is suggested that these cultivars should be preferentially used as sources for resistance to rust in breeding programs targeting development lines adapted to the state of Minas Gerais.

Caracterização de linhagens endogâmicas recombinantes e mapeamento de locos de características quantitativas associados a ciclo e produtividade do feijoeiro-comum

O objetivo deste trabalho foi caracterizar 154 linhagens endogâmicas recombinantes por meio da avaliacao de caracteristicas quantitativas, morfologicas, moleculares e de resistencia a doencas e mapear locos de caracteristicas quantitativas associados a ciclo e produtividade do feijoeiro-comum. Adotando o valor do limite de deteccao (LOD) de 4,0 e uma frequencia maxima de recombinacao de 0,40, foram mapeados 43 marcadores em nove grupos de ligacao cobrindo uma distância de recombinacao total de 247,8 cM. A distância entre marcadores adjacentes variou entre 0 e 28 cM, com media de 7,3 cM. Os grupos de ligacao variaram em tamanho de 2,3 a 61,2 cM. Os genes de resistencia a ferrugem e a antracnose ficaram localizados no mesmo grupo de ligacao. Foram mapeados locos associados as oito caracteristicas quantitativas estudadas, e a explicacao da variância fenotipica pelos marcadores variou de 14,03% a 40,14%. Os resultados encontrados lancam bases para o desenvolvimento de mapas especificos saturados e de utilidade em programas de melhoramento do feijoeiro-comum.

Caracterização fenotípica e molecular de genitores de feijão tipo carioca quanto à resistência a patógenos

Abstract€–€The present study aimed at the phenotypic and molecular characterization of 31€genotypes of thecarioca-type common bean regarding the resistance to anthracnose, rust and angular leaf spot (ALS) pathogens.Thirteen pathotypes of Colletotrichum lindemuthianum , two of Uromyces appendiculatus and seven of Pseudocercospora griseola were inoculated. In the molecular characterization, five molecular markers, identifiedin advance, and linked to the different alleles of pathogens’ resistance, were used. Seven genotypes showedresistance to 12€pathotypes of C.€lindemuthianum . Nine genotypes presented resistance to five pathotypes of P.€griseola . Ten genotypes were resistant to the pathotypes of U.€appendiculatus . The lines VC€2, VC€3 andVC€5, besides Ruda-R (line pyramided with five genes which confer resistance to some pathotypes of anthracnose,rust and ALS), were the stood out for multiple resistance to the pathogens above described. Molecularpolymorphism was detected between the most genotypes with Ruda-R, which indicates the possibility of usingthe molecular markers SCARF10, SCAR Y20, SCARAZ20, SCARH13 and OPX1 1 .Index terms:

DNA marker-assisted selection to pyramid rust resistance genes in “carioca” seeded common bean lines

This work reports a gene pyramiding approach assisted by DNA markers used to develop “carioca” seeded common bean (Phaseolus vulgaris L.) elite lines harboring three different rust resistance genes. Rust is among the most destructive diseases that attack P. vulgaris and cause serious damage worldwide. The rust resistance genes Ur-5 (from ‘Mexico 309’), Ur-11 (from ‘BelMiDak RR-3’), and Ur-14 (from ‘BRS Pioneiro’, a “carioca” seeded cultivar derived from the resistance source ‘Ouro Negro’) were combined in the “carioca” seeded bean cultivar ‘Rudá’. Firstly, two different backcross programs were conducted separately to produce progenies harboring individually the Ur-5 and Ur-11 genes. Molecular fingerprinting analysis was used to select plants genetically similar to ‘Rudá’ in the backcross cycles to accelerate the recurrent-background recovery. The obtained progenies were initially intercrossed and then crossed with ‘BRSMG Pioneiro’ (Ur-14). The final F1 plants derived from these crosses were screened with DNA markers linked to the three rust resistance genes: SI19 (Ur-5), SAE19 (Ur-11) and OPX11 (Ur-14). The plants selected as harboring all the alleles of interest were used to obtain the next generations. The selection based on DNA markers was conducted up to the F4:5 generation. We were able to select F4:7 progenies showing all the DNA markers associated to the genes of interest and resistant to all specific races of U. appendiculatus used for phenotypically detecting each one of the rust resistance genes. Yield evaluations show that these selected lines are as productive as the recurrent parent ‘Rudá’ and high-performing control cultivars grown in Brazil.

Growth and nodulation of soybean plants fertilized with poultry litter

Nowadays much of the chemical fertilizers used in Brazil come from imports, what creates the necessity to seek for alternative fertilizers. One possibility is organic fertilizers, including poultry litter, which presents increasing availability in various regions of the country, due to the expansion of the poultry industry. Despite its availability, there are no enough studies that show the benefits of using poultry litter on soybeans in substitution of mineral fertilizer. The present study aimed to evaluate the effect of different doses of poultry litter on leaf chlorophyll content, nodulation, and development of soybean plants. It was used a completely randomized design with five doses of poultry litter (0, 1, 2, 4 and 8 t ha-1) and a control with mineral fertilizer with four repetitions. On stages R1 and R5, chlorophyll readings were done using a portable meter and also the measurement of plant height. Plants were cut near the surface, roots were washed and the nodules were detached and counted. After that, it was determined the dry weight of plant roots, nodules, and shoots. Soybean fertilization with poultry litter increases the chlorophyll content of leaves, plant height, shoot dry matter, root dry matter, and nodulation. The use of poultry litter on soybean favors its growth with decreasing increments, except for root dry matter, and with an optimum dose for each variable. The supply of poultry litter can replace mineral fertilizers in terms of soybean growth.

Recommendation of liming at variable rates under different sampling intensities.

The aim of this work was to study the variability and spatial dependence of soil properties and their effects on lime recommendation with three simulated sampling intensities. In an area of 725.9 ha, 154 samples were collected at a distance of 225 m in a regular grid. Samples were discarded within the spatial dependence range and two other data sets were created, with 76 and 38 samples each. Geostatistical analyses were performed for the variables, cation exchange capacity and sum of bases. After kriging interpolation of the variables lime recommendation maps were elaborated for the three data sets. In comparison with the traditional recommendation method, on average, there was no reduction on lime requirement. Differences among the three recommendation rates were noted, specially on spatial distribution of doses. On the other hand, assuming as correct recommendation with higher number of samples, the use of a lower intensity sampling strategy is viable due to the cost reduction and acceptable difference among recommendations.

Weeds Variability Evaluation on No-Tillage System Using Digital Images

The aim of this work was to describe the weed spatial variability in a no-tillage system area in Jatai, GO, Brazil. A regular grid was used on a 25 hectares field accomplishing 36 sample points. The total shoot dry matter of weeds was determined on an area of 0.5 m2 and also separated on broadleaf and grassy types. Images of the sample area were sorted by a supervised classifier into three classes: straw, leaves and uncovered. The soybean leaves were manually segmented from the leave class. The images were also processed using an automatic threshold method, separating the leaves from the background. On the processed images were calculated the covered areas by each class. All the variables were submitted to correlation and geostatistical analysis. A significant correlation was verified between covered area by plants and the shoot dry matter. The supervised classification and the automatic threshold method achieved similar results. When the soybean leaves was segmented, the calculation of the broadleaf weed infestation was improved. Spatial dependence was only verified when the two types of weeds were studied separately.