Irajá Ferreira Antunes

Atividade de peroxidase e polifenoloxidase na resistência do feijão à antracnose

The objective of this work was to evaluate the influence of peroxidase and polyphenol oxidase enzymes in anthracnose resistance of four bean cultivars. Seedlings were sprinkled with salicylic acid and delta race of Colletotrichum lindemuthianum (inducer fungus) and after three days they were inoculated with 33/95 virulent pathotype of C. lindemuthianum. Enzyme activity and phenol levels were evaluated three days after inducer fungus application and five days after inoculation with virulent pathotype. Plants treated with salicylic acid and inducer fungus presented higher activity increases of both enzymes, in all cultivars. Higher impulses in enzymatic activity were observed in cultivars with higher disease resistance. One isoperoxidase appeared in treatments with inducer fungus, salicylic acid, after inoculation with virulent pathotype, and in control plants, in AB 136, Rio Tibagi and Macanudo cultivars. Positive correlation was observed among peroxidase and polyphenol oxidase activity, phenolic compound levels and anthracnose resistance.

Induction of chalcone synthase and phenylalanine ammonia-lyase by salicylic acid and Colletotrichum lindemuthianum in common bean

The activities of the enzymes chalcone synthase (CHS) and phenylalanine ammonia-lyase (PAL) were measured in leaf extracts obtained from four cultivars of the common bean (AB 136, Rio Tibagi, Carioca and Macanudo). Two stages of plant development were examined: plantlets (V2) and the onset of blooming (R6). Initially, the plants were either treated with salicylic acid or inoculated with the delta race of Colletotrichum lindemuthianum (inductive fungus) and after three days they were evaluated for enzyme activity. Afterwards, all plants were inoculated (challenged) with the virulent pathotype 33/95 of C. lindemuthianum except for the water control. Five days later, the activities of PAL and CHS were evaluated. There were significant changes in the activities of both enzymes three days after treatment with salicylic acid or inductive fungus when compared to the control. Five days after inoculation with with the virulent pathotype 33/95 of C. lindemuthianum CHS activity in the Macanudo was similar to control plants that were not treated with salicylic acid or the inductive fungus but inoculated with 33/95 C. lindemuthianum. The increase in enzyme activity after challenge with 33/95 C. lindemuthianum was greatest for the salicylic acid treatment in the cultivar AB 136, followed by Rio Tibagi and Carioca.

Divergência genética entre cultivares locais e cultivares melhoradas de feijão

A grande variabilidade genetica presente no germoplasma de feijao (Phaseolus vulgaris L.) em uso na agricultura familiar no Brasil tem sido plenamente reconhecida. A eficiencia da conservacao e o aproveitamento desta variabilidade aumentam quando esta e devidamente caracterizada. O objetivo deste trabalho foi caracterizar a variabilidade genetica de parte do germoplasma existente em poder de produtores de feijao no Rio Grande do Sul, e de cultivares produzidas pela pesquisa, e reuni-las em grupos de similaridade genetica. Foi avaliada a divergencia genetica de 37 cultivares locais (land races) e 14 cultivares indicadas pela pesquisa no Estado, utilizando 40 descritores morfologicos; a grande maioria desses descritores sao necessarios a protecao legal. Empregou-se analise multivariada, por intermedio de componentes principais e metodo de agrupamento. O uso destas tecnicas possibilitou identificar descritores ineficientes ou redundantes no estudo da variabilidade genetica e reunir as cultivares estudadas em quatro grupos distintos de similaridade genetica. As cultivares locais revelaram variabilidade superior a encontrada nas cultivares oriundas da pesquisa, o que sugere a importância da sua inclusao em programas de melhoramento.

Inheritance of root traits and phosphorus uptake in common bean (Phaseolus vulgaris L.) under limited soil phosphorus supply

Scarce information about genetic control of root traits in common bean (Phaseolus vulgaris L.) impedes a more effective exploitation of the reported variability for plant breeding. This work investigated the inheritance of traits related to the root system and P absorption of common bean grown under limited soil P supply. Two experiments were carried out, each one involving one family of crosses comprising six populations (two parental cultivars, F1, F2, and two backcrosses). One plant was grown per pot with 3 kg of soil (7 mg P kg−1 Mehlich-1) and harvested at pod setting. Root samples provided the root surface area and root length by digital image analysis. Considerable additive genotypic effects were detected in both experiments; additive × additive epistases were significant only in the second experiment, whereas dominance effects were seldom significant. Estimated broad-sense heritabilities were 0.55 and 0.51 for root area, 0.50 and 0.47 for root length, 0.51 and 0.61 for root mass, and 0.51 and 0.43 for the total P content, in the first and second experiments, respectively. High genotypic correlation between root mass and root area justifies screening genotypes based solely on root mass. Phenotypic and genotypic correlations between shoot mass and root mass, and shoot mass and total P content, were highly significant, indicating that direct selection for higher shoot growth of bean plants under limited soil P supply would result in increased root mass and P uptake. A scheme for root breeding in common bean towards improving P efficiency should include: matching cultivars with favourable alleles; advance until later generations without any selection; selection of resultant genotypes under low soil P supply via shoot growth; evaluation of promising lines for root growth and agronomic performance.

Avaliação de espaçamentos e populações de plantas de feijão visando à colheita mecanizada direta

8 RESUMO - O trabalho foi conduzido na safra 1992/93, no Centro Agropecuario Palma (CAP)/Univer- sidade Federal de Pelotas (UFPel), objetivando avaliar o efeito da variacao do espacamento entre linhas e da populacao de plantas sobre caracteristicas agronomicas relacionadas com a colheita mecanizada de feijoeiro (Phaseolus vulgaris L.). Foram testados tres espacamentos entre linhas (25, 50 e 75 cm) e quatro populacoes de plantas/ha (100, 200, 350 e 500 mil), utilizando como reagente a cultivar Pampa, de habito de crescimento indeterminado, tipo II. O delineamento experimental foi em blocos casualizados, com quatro repeticoes. Somente ocorreu interacao entre os fatores para o indice de acamamento, onde o aumento da populacao tendeu a reduzi-lo. A combinacao do maior espacamento com a menor populacao provocou o maior acamamento. A reducao no espacamento entre linhas, apesar de reduzir a altura de plantas, a altura de insercao de vagens e o rendimento de graos, provocou aumento na altura da ponta da vagem mais baixa ate o solo, e reducao na porcentagem de plantas com vagens encostando no solo. O aumento na populacao de plantas, apesar de nao afetar a maioria das caracteristicas agronomicas das plantas, provocou reducao na porcentagem de plantas com vagens encostando no solo, e nao provocou modificacoes no rendimento de graos. Termos para indexacao: Phaseolus vulgaris, acamamento, insercao de vagens. SPACING AND PLANT POPULATION FOR DRY BEAN HARVEST MECHANIZATION ABSTRACT - The experiment was conducted in 1992/93 season at Centro Agropecuario da Palma (CAP) of the Universidade Federal de Pelotas (UFPel), in Pelotas, Brazil, to evaluate the effect of spacing variations between rows and plant populations on agronomic characteristics related to mechanized harvest for dry bean (Phaseolus vulgaris L.). Three different row spacing (25, 50 and 75 cm) and four different plant populations/ha (100, 200, 350 and 500 thousand) were used, utilizing the cultivar Pampa, indeterminate growth habit type II as reagent. The field trial was in randomized blocks, with four replications. Positive interaction between factors was observed for the lodging index, where the increase in the plant population tended to reduce it. The combination of larger spacing with smaller plant population resulted in a higher lodging index. The reduction in the row spacings, in spite of reducing the plant height, the pod insertion height and the grain yield, resulted in an increase of the lowest pod tip height and in a reduction of the percentage of plants with pods touching the soil surface. The increase in the plant population, despite of not affecting the majority of the agronomic characteristics of the plant, resulted in a reduction of the percentage of plants with pods touching the soil and did not cause any alteration in the grain yield.The experiment was conducted in 1992/93 season at Centro Agropecuario da Palma (CAP) of the Universidade Federal de Pelotas (UFPel), in Pelotas, Brazil, to evaluate the effect of spacing variations between rows and plant populations on agronomic characteristics related to mechanized harvest for dry bean (Phaseolus vulgaris L.). Three different row spacing (25, 50 and 75 cm) and four different plant populations/ha (100, 200, 350 and 500 thousand) were used, utilizing the cultivar Pampa, indeterminate growth habit type II as reagent. The field trial was in randomized blocks, with four replications. Positive interaction between factors was observed for the lodging index, where the increase in the plant population tended to reduce it. The combination of larger spacing with smaller plant population resulted in a higher lodging index. The reduction in the row spacings, in spite of reducing the plant height, the pod insertion height and the grain yield, resulted in an increase of the lowest pod tip height and in a reduction of the percentage of plants with pods touching the soil surface. The increase in the plant population, despite of not affecting the majority of the agronomic characteristics of the plant, resulted in a reduction of the percentage of plants with pods touching the soil and did not cause any alteration in the grain yield.

Adaptabilidade e estabilidade do rendimento de grãos de genótipos de feijão

Adaptation and stability analysis of grain yield of eleven bean (Phaseolus vulgarisL.) genotypes were performed using data collected from trials carried out in 23 locations of Rio Grande do Sul State (Brazil), from 1988/89 to 1993/94, comprising 72 environments. The objective was to identify the best genotypes for cultivation throughout the state as well as for breeding purposes. Genotypes, were Rio Tibagi, Guateian 6662, EMPASC201, FT 120, Macanudo, Pampa, Minuano, Macotaco, CNF 5491, Carioca and Irai. Segmented regression method with estimated join point was used. Absence of significant alteration of the genotype individual linear response rates indicated the linear regression method as appropriate for this study. All genotypes presented significant regression deviation, characterizing phenotypic instability. Genotypes differed in regard to average yield and response rate, being classified as: Minuano, Macotaco, CNF 5491 and Macanudo of general adaptation; Rio Tibagi, Pampa and Irai of poor adaptation to all environments; Guateian 6662 and EMPASC201 of specific adaptation to poor environments; genotypes FT 120 and Carioca of average adaptation to all environments. These results pointed out Minuano, Macotaco, CNF 5491 and Macanudo as the most productive and best adapted to the considered environments. These genetically related genotypes displayed similar adaptability among themselves and different from the others as well as no differential stability from some of them.

Eficiência de coeficientes de similaridade em genótipos de feijão mediante marcadores RAPD

O objetivo deste trabalho foi avaliar a eficiencia de coeficientes de similaridade em genotipos de feijao por meio de marcadores RAPD. A eficiencia dos coeficientes de similaridade de Jaccard, Sorensen-Dice, Russel e Rao, Ochiai, Coincidencia Simples, Rogers e Tanimoto, Hamann, Kulczynski 2, Yule e Phi no agrupamento de 35 cultivares locais e comerciais de feijao foi analisada com base em 104 marcadores RAPD. Os coeficientes foram comparados por dendrogramas, pela eficiencia da projecao no espaco bidimensional e por grupos formados pelo metodo de otimizacao de Tocher. Os diferentes coeficientes de similaridade apresentaram variacao quanto a eficiencia de projecao no espaco bidimensional e quanto ao numero de grupos formados pelo metodo de otimizacao de Tocher. Os coeficientes de Russel e Rao e de Yule sao os mais discordantes, e os coeficientes de Sorensen-Dice, Ochiai e Kulczynski 2 sao mais eficientes que os demais. O coeficiente de Russel e Rao nao tem a capacidade de agrupar as cultivares em seus respectivos centros de domesticacao.

Estabilidade de produção de cultivares de feijão de diferentes grupos comerciais no Estado do Rio Grande do Sul

The objective of this research was to evaluate the adaptability and yield stability of common bean cultivars for the cultivation in the Rio Grande do Sul State. Sixteen common bean cultivars of different commercial groups were evaluated in three growing seasons, in 20 environments, in the Rio Grande do Sul State. The adaptability and stability estimates were obtained for the methods of Eberhart and Russel and Lin and Binns, modified to Carneiro. Significative cultivars x environments interaction were observed for grain yield indicating different responses of the cultivars to the assayed locations and years. The results showed that the two methods gave similar results in the identification of cultivars with yield stability (Guapo Brilhante) and with adaptability to favorable environment (BRS Expedito e TPS Bonito). The Guapo Brilhante cultivar showed high grain yield, with adaptability and yield stability for cultivation in the Rio Grande do Sul State.

Indução de resistência sistêmica à antracnose em feijoeiro-comum pela raça delta avirulenta de Colletotrichum lindemuthianum

The objectives of this work were to evaluate the potential of the avirulent delta race of Colletotrichum lindemuthianum as a protector against virulent races of this fungus and induce systemic resistance to anthracnose in common bean (Phaseolus vulgaris). Four common bean cultivars were evaluated for changes in the activities of beta-1,3-glucanase and chitinase at two common bean developmental stages, V2 and R6, three days after the infection with delta race of C. lindemuthianum, in comparison with control applications of water and salicylic acid. The plants were then infected with a spore suspension of 33/95, a virulent C. lindemuthianum patotype and reevaluated five days later for the enzyme activities. Significant increases in the activities of both beta-1,3-glucanase and chitinase were observed after inoculation of inductive fungus at the two evaluation periods, at both plant development stages. The activities of both beta-1,3-glucanase and chitinase varied among cultivars and among plant development stages. A significant correlation was observed between the disease severity and the enzyme activity. The avirulent delta race of C. lindemuthianum reduced the severity of anthracnose on common bean and may have the potential to control the disease.

Diversidade genética em cultivares locais e comerciais de feijão baseada em marcadores RAPD

Abstract – The objective of this work was to characterize the genetic diversity within and amongcultivars and landraces of common bean from RAPD markers analysis, and to evaluate the capacity ofthis markers in clustering common bean genotypes according to domestication centers and seed color.Thirty five common bean genotypes including 13 commercial cultivars and 22 landraces, from State ofRio Grande do Sul, Brazil, were evaluated. Genetic distances were calculated using Sorensen-Dice’ssimilarity coefficient, displayed in a dendrogram. RAPD markers were efficient in separating cultivarsand landraces according to domestication centers, but not according to seed color. Mesoamericancommercial cultivars and landraces have been clustered in different groups. A high degree of similaritywas observed among cultivars in use in Rio Grande do Sul.Index terms: Phaseolus vulgaris , genetic variation, cluster analysis. (1) Aceito para publicacao em 18 de agosto de 2003.Extraido da tese de doutorado apresentada pelo primeiro autora Universidade Federal de Pelotas (UFPel), Pelotas, RS.