Antixenosis of bean genotypes to Chrysodeixis includens (Lepidoptera: Noctuidae)

The objective of this work was to evaluate bean genotypes for resistance to soybean looper (Chrysodeixis includens). Initially, free-choice tests were carried out with 59 genotypes, divided into three groups according to leaf color intensity (dark green, light green, and medium green), in order to evaluate oviposition preference. Subsequently, 12 genotypes with high potential for resistance were selected, as well as two susceptible commercial standards. With these genotypes, new tests were performed for oviposition in a greenhouse, besides tests for attractiveness and consumption under laboratory conditions (26±2ºC, 65±10% RH, and 14 h light: 10 h dark photophase). In the no-choice test with adults, in the greenhouse, the 'IAC Jabola', Arcelina 1, 'IAC Boreal', 'Flor de Mayo', and 'IAC Formoso' genotypes were the least oviposited, showing antixenosis-type resistance for oviposition. In the free-choice test with larvae, Arcelina 4, 'BRS Horizonte', 'Pérola', H96A102-1-1-1-52, 'IAC Boreal', 'IAC Harmonia', and 'IAC Formoso' were the less consumed genotypes, which indicates antixenosis to feeding. In the no-choice test, all genotypes (except for 'IAPAR 57') expressed moderate levels of antixenosis to feeding against C. includens larvae.

Longitudinal distribution of bean seeds in horizontal plate meter operating with one or two seed outlets

This study aimed to evaluate the effect of horizontal plate meter with oblong holes operating with one or two seed outlets at different speeds over the accuracy of longitudinal distribution of common bean seeds (Phaseolus vulgaris L.). The experiment was performed in laboratory using the meter with one and two seed outlet points in relation to ten tangential disk plate speeds (0.03 to 0.30 m s-1). It was used a complete randomized design with four replications, summing up 80 experimental treatments. Tangential speed quantitative factor was estimated through a 2nd order polynomial regression. There was no significant difference in the behavior of the seed meter operating with one or two outlets in the metering of bean seeds in all tested speeds, with percentage of single seeds spacing over 60% in tangential speeds below of 0.24 m s-1.

Modeling of weeds interference periods in bean

The research objective was to determine the effects of spacing and seeding density of common bean to the period prior to weed interference (PPI) and weed period prior to economic loss (WEEPPEL). The treatments consisted of periods of coexistence between culture and the weeds, with 0 to 10, 0 to 20, 0 to 30, 0 to 40, 0 to 50, 0 to 60, 0 to 70, and 0 to 80 days and a control maintained without weeds. In addition to the periods of coexistence, there were still studies with an inter-row of 0.45 and 0.60 m, 10 and 15 plants m-1. The experimental delineation used was randomized blocks with four repetitions per treatment. The grain productivity of the culture had a reduction of 63, 50, 42 and 57% when the coexistence with the weed plants was during the entire cycle of the culture for a row spacing of 0.45 m and a seeding density of 10 and 15 plants per meter; and a row spacing of 0.60m and a seeding density of 10 and 15 plants per meter, respectively. The PPI occurred in 23, 27, 13, and 19 days after crop emergence and WEEPPEL in 10, 9, 8, and 8 days, respectively.

In vitro protein digestibility of enzymatically pre-treated bean (Phaseolus vulgaris L.) flour using commercial protease and Bacillus sp. protease

The common bean (Phaseolus vulgaris L.) is a staple food in the Brazilian diet and represents the major source of dietary protein and other micronutrients and minerals. Despite the considerable protein concentration in beans, the food is considered of low biological value when compared to animal proteins and other plant protein sources. To improve the availability of protein in beans, enzymatic treatments were performed in four cultivars (ON, OPNS, TAL and VC3). The approach was a completely randomized design with four replicates. We used a 4 × 3 factorial arrangement (four cultivars and three treatments: treatment 1-addition of commercial protease (Trypsin 250, Difco), treatment 2-addition of protease from Bacillus sp., and treatment 3:-control without enzyme addition). The enzyme: substrate ratio was 5% w/w (amount of enzyme per total protein in bean flour). The approach was a completely randomized design with four replicates. A 4 × 3 factorial arrangement (four cultivars and three treatments, the same as those mentioned above) was used. The concentration of total protein (g.100 g-1 of dry matter) in the samples ranged from 16.94 to 18.06%, while the concentration of total phenolics was between 0.78 and 1.12% (g Eq. tannic acid.100 g-1 dry matter). The in vitro protein digestibility of enzymatically untreated bean flour (control) ranged from 47.30 to 56.17% based on the digestibility of casein. Concentrations of P, K, Ca, Mg, and Zn observed in the four cultivars tested were within the average values available in the literature. Treatment 2 with protease from Bacillus sp. induced decreases in the levels of Cu and Mn. The average Fe content increased in all bean flour samples when treated with proteases, reaching a maximum increase of 102% in the TAL flour treated with protease from Bacillus sp. The digestibility of all beans tested was significantly increased (p < 0.05) after the enzyme treatment. The greatest change was observed in the OPNS cultivar treated with protease from Bacillus sp., which increased its digestibility from 54.4% (control treatment) to 81.6%.

Cultivar, harvest year, and storage conditions affecting nutritional quality of common beans (Phaseolus vulgaris L.

Sixteen common bean cultivars were compared concerning the physicochemical characteristics of their raw seeds in the course of two consecutive harvests, as well as the effect of storage conditions on starch and dietary fiber content of cooked beans. Using cluster analysis it was possible to identify groups of cultivars with different nutritional features. Bean cultivars were categorized into four different groups according either to their macronutrient content (crude protein-PROT, total dietary fiber-TDF, insoluble dietary fiber-IDF, soluble dietary fiber-SDF, digestible starch-DS, and resistant starch-RS) or to their micronutrient levels (Fe, Zn, Mn, Cu, Ca, Mg, and P). Guateian 6662 and Rio Tibagi appeared to be the most suitable cultivars to prevent nutritional deficiencies, because they had high PROT, DS, Fe, and Zn content. The high total dietary fiber and RS content of Iraí, Minuano, and TPS Bonito cultivars, and specially the high soluble fiber content of Guateian 6662 and Rio Tibagi cultivars suggests that they could have a beneficial role in controlling blood lipid and glucose levels. Cooked beans had a decrease in DS and an increase in RS content after storage (4 °C or -20 °C), but these changes were more prominent in beans that had low RS content before cooking than in those of high RS content. TDF, IDF, and SDF did not change after storage.

Germination, initial growth and cotyledon protein content of bean cultivars under salinity stress

Excess salts in the root zone inhibit water uptake by plants, affect nutrient uptake and may result in toxicities due to individual salts in the soil solution. Excess exchangeable sodium in the soil may destroy the soil structure to a point where water penetration and root aeration become impossible. Sodium is also toxic to many plants. Beans (Phaseolus vulgaris L.) are consumed as protein source in northeastern Brazil, although little is known about common bean cultivar tolerance to salinity. The germination of bean cultivars under salt stress was studied. The cultivars 'Carioca' and 'Mulatinho' were submitted to germination test in a germinator at 25ºC, at the Seed Analysis Laboratory of the Brazilian Agricultural Research Corporation unit in the Semi- Arid region (Embrapa Semi Árido), Petrolina, Pernambuco State. These seeds were germinated on "germitest" papers imbibed in distilled water or in 10, 50, 100 e 200 mol.m-3sodium chloride (NaCl) solutions. At the first and second counts of the germination test, normal seedlings were counted, measured, weighed and dried, supplying data for vigor, total germination, fresh matter weight and dry matter weight and seedlings length. Total protein was quantified in cotyledons at 3, 6 and 9 days after sowing. The results indicated that the NaCl content influenced seed germination and concentrations above 50 mol.m-3 decreased germination and seedling growth.

Diversity, phylogeny and distribution of bean rhizobia in salt-affected soils of North-West Morocco

Different molecular methods: BOX-PCR fingerprinting, R-FLP-PCR and sequencing of the 16S rDNA as well as the symbiotic genes nodC and nifH, were used to study the genetic diversity within a collection of nodulating bean rhizobia isolated from five soils of North-West Morocco. BOX fingerprints analysis of 241 isolates revealed 19 different BOX profiles. According to the PFLP-PCR and sequencing of 16S rDNA carried out on 45 representative isolates, 5 genotypes were obtained corresponding to the species Rhizobium etli, R. tropici, R. gallicum, R. leguminosarum and Sinorhizobium meliloti. The most abundant species were R. etli and R. tropici (61% and 24%, respectively). A high intraspecific diversity was observed among the R. etli isolates, while the R. tropici group was homogeneous. Most of the rhizobia studied belong to species known to nodulate common bean, while 2 species were unconventional microsymbionts: R. leguminosarum biovar viciae and S. meliloti. Our results, especially the nodulation promiscuity of common bean and the relation between the predominance of some species of rhizobia in particular soils and the salt content of these soils, indicate that there is a real need for a better understanding of the distribution of common bean rhizobia species in the soils of Morocco before any inoculation attempt.

Confocal imaging of pseudomonas syringae pv. phaseolicola colony development in bean reveals reduced multiplication of strains containing the genomic island PPHGI-1.

Pseudomonas syringae pv. phaseolicola is the seed borne causative agent of halo blight in the common bean Phaseolus vulgaris. Pseudomonas syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene hopAR1 (located on a 106-kb genomic island, PPHGI-1, and earlier named avrPphB), which matches resistance gene R3 in P. vulgaris cultivar Tendergreen (TG) and causes a rapid hypersensitive reaction (HR). Here, we have fluorescently labeled selected Pseudomonas syringae pv. phaseolicola 1302A and 1448A strains (with and without PPHGI-1) to enable confocal imaging of in-planta colony formation within the apoplast of resistant (TG) and susceptible (Canadian Wonder [CW]) P. vulgaris leaves. Temporal quantification of fluorescent Pseudomonas syringae pv. phaseolicola colony development correlated with in-planta bacterial multiplication (measured as CFU/ml) and is, therefore, an effective means of monitoring Pseudomonas syringae pv. phaseolicola endophytic colonization and survival in P. vulgaris. We present advances in the application of confocal microscopy for in-planta visualization of Pseudomonas syringae pv. phaseolicola colony development in the leaf mesophyll to show how the HR defense response greatly affects colony morphology and bacterial survival. Unexpectedly, the presence of PPHGI-1 was found to cause a reduction of colony development in susceptible P. vulgaris CW leaf tissue. We discuss the evolutionary consequences that the acquisition and retention of PPHGI-1 brings to Pseudomonas syringae pv. phaseolicola in planta.

Pseudomonas syringae pv. phaseolicola: from ‘has bean’ to supermodel

Pseudomonas syringae pv. phaseolicola causes halo blight of the common bean, Phaseolus vulgaris, worldwide and remains difficult to control. Races of the pathogen cause either disease symptoms or a resistant hypersensitive response on a series of differentially reacting bean cultivars. The molecular genetics of the interaction between P. syringae pv. phaseolicola and bean, and the evolution of bacterial virulence, have been investigated in depth and this research has led to important discoveries in the field of plant-microbe interactions. In this review, we discuss several of the areas of study that chart the rise of P. syringae pv. phaseolicola from a common pathogen of bean plants to a molecular plant-pathogen supermodel bacterium. Taxonomy: Bacteria; Proteobacteria, gamma subdivision; order Pseudomonadales; family Pseudomonadaceae; genus Pseudomonas; species Pseudomonas syringae; Genomospecies 2; pathogenic variety phaseolicola. Microbiological properties: Gram-negative, aerobic, motile, rod-shaped, 1.5 µm long, 0.7-1.2 µm in diameter, at least one polar flagellum, optimal temperatures for growth of 25-30 °C, oxidase negative, arginine dihydrolase negative, levan positive and elicits the hypersensitive response on tobacco. Host range: Major bacterial disease of common bean (Phaseolus vulgaris) in temperate regions and above medium altitudes in the tropics. Natural infections have been recorded on several other legume species, including all members of the tribe Phaseoleae with the exception of Desmodium spp. and Pisum sativum. Disease symptoms: Water-soaked lesions on leaves, pods, stems or petioles, that quickly develop greenish-yellow haloes on leaves at temperatures of less than 23 °C. Infected seeds may be symptomless, or have wrinkled or buttery-yellow patches on the seed coat. Seedling infection is recognized by general chlorosis, stunting and distortion of growth. Epidemiology: Seed borne and disseminated from exudation by water-splash and wind occurring during rainfall. Bacteria invade through wounds and natural openings (notably stomata). Weedy and cultivated alternative hosts may also harbour the bacterium. Disease control: Some measure of control is achieved with copper formulations and streptomycin. Pathogen-free seed and resistant cultivars are recommended. Useful websites: Pseudomonas-plant interaction http://www.pseudomonas-syringae.org/; PseudoDB http://xbase.bham.ac.uk/pseudodb/; Plant Associated and Environmental Microbes Database (PAMDB) http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; PseudoMLSA Database http://www.uib.es/microbiologiaBD/Welcome.html.

Susceptibility of faba bean (Vicia faba L.) to heat stress during floral development and anthesis

Experiments were conducted over two years to quantify the response of faba bean (Vicia faba L.) to heat stress. Potted winter faba bean plants (cv. Wizard) were exposed to temperature treatments (18/10; 22/14; 26/18; 30/22; 34/26°C day/night) for five days during floral development and anthesis. Developmental stages of all flowers were scored prior to stress, plants were grown in exclusion from insect pollinators to prevent pollen movement between flowers, and yield was harvested at an individual pod scale, enabling effects of heat stress to be investigated at a high resolution. Susceptibility to stress differed between floral stages, flowers were most affected during initial green-bud stages. Yield and pollen germination of flowers present before stress showed threshold relationships to stress, with lethal temperatures (t50) ~28°C and ~32°C, while whole plant yield showed a linear negative relationship to stress with high plasticity in yield allocation, such that yield lost at lower nodes was partially compensated at higher nodal positions. Faba bean has many beneficial attributes for sustainable modern cropping systems but these results suggest that yield will be limited by projected climate change, necessitating the development of heat tolerant cultivars, or improved resilience by other mechanisms such as earlier flowering times.

Modeling of weeds interference periods in bean

Objetivou-se com este trabalho determinar o período de convivência anterior à interferência das plantas daninhas (PAI) e o período anterior ao dano no rendimento econômico (PADRE) na cultura do feijão, em diferentes espaçamentos (0,45 e 0,60 m) e densidade de plantas (10 e 15 plantas m-1). Os tratamentos foram constituídos de períodos de convivência entre a cultura e as plantas daninhas (0 a 10, 0 a 20, 0 a 30, 0 a 40, 0 a 50, 0 a 60, 0 a 70 e 0 a 80 dias), mais uma testemunha sem convívio com as plantas daninhas. Adotou-se o delineamento experimental de blocos casualizados, com quatro repetições. Os períodos anteriores à interferência (PAI) da cultura foram de 23, 27, 13 e 19 dias após emergência, e os períodos anteriores ao dano no rendimento econômico (PADRE), de 10, 9, 8 e 8 dias, para os tratamentos com espaçamento de 0,45 m e densidades de semeadura de 10 e 15 plantas m-1 e para aqueles com espaçamento de 0,60 m e densidades de semeadura de 10 e 15 plantas m-1, respectivamente, o que reduziu a produtividade de grãos em 63, 50, 42 e 57%, respectivamente, com a presença das plantas daninhas durante todo o ciclo do feijoeiro.

Resposta de cultivares de feijoeiro comum à calagem superficial em semeadura direta

Soil acidity in no tillage system, if not in high situations, can be neutralized by lime surface application, improving mineral nutrition and crop yield. Aiming to evaluate the agronomic performance of common bean cultivars, to surface lime application, in no tillage system, an experiment was conducted in Oxisol, Botucatu Municipal District, São Paulo State, Brazil. The experimental design was a complete randomized block in split plot with four replications, where the plots were formed by common bean cultivars (Carioca, IAC Carioca Ete, Perola, IAPAR 81 e Campeao 2) and subplots consisted of surface application of dolomitic limestone (zero, 1.8 t ha(-1), 3.6 t ha(-1) and 5.4 t ha(-1)). The surface lime application on the soil occurred in October 2002 and subsequently the sequence millet (spring) - beans (summer) - oat (autumn-winter) were planted under rainfed conditions. Bean cultivars sowing were done on December 17, 2003. It can be concluded that there is influence of cultivars and limestone surface application under no tillage, where IAPAR 81 showed better grain yield with the increase of lime rates, obtaining values of 2,025 kg ha(-1) without the lime application to 2,655 kg ha(-1) with 5.4 t ha(-1) lime rate, obtaining 31% yield increase.

Formação e manutenção de palhada de gramíneas concomitante à influência da adubação nitrogenada em cobertura no feijoeiro irrigado em sistema de semeadura direta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adubação nitrogenada de cobertura no feijoeiro de invernoprimavera em três sistemas de cultivo

The aim of this study was to evaluate the nitrogen topdressing influence in common bean irrigated (winter-spring), in the first year of no tillage implementation. The experimental design was split-plot with three replications in randomized blocks. The plots were formed by three types of ground cover, corn-grain, corn-grain intercropped with Brachiaria ruziziensis and only B. ruziziensis. The subplots were formed by five doses of nitrogen topdressing (0, 40, 80, 120 and 160 kg ha(-1)), using urea as nitrogen source. It was determined the dry mass of residue present as ground cover, the full flowering time, the leaf nitrogen content, the 100 grains mass, the grain yield, the processing income, the chemical soil properties and economic analysis of common bean grain yield. It was found the common bean grain productivity in succession to corn-grain was positively influenced by nitrogen fertilization, showing it is economically viable only when given 160 kg ha(-1) of nitrogen and the intercropping corn-grain and B. ruziziensis use is the best option when the common bean is sown in succession.

Adubação de cultivares de feijoeiro comum em várzeas tropicais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)