Common Bean Grain Research Articles

Co-inoculation of cyanobacteria, rhizobia, and azospirilla associated with fertilizer N increases the common bean grain yield

A large number of beneficial microorganisms have been used as inoculants in agriculture to increase grain yield. The objective of the study was to evaluate the response of common bean (Phaseolus vulgaris) to inoculation and co-inoculation with rhizobia, azospirilla and cyanobacteria combined with doses of N-fertilizer. A field experiment was carried out in two growing seasons to assess twelve treatments using single and combined inoculation of rhizobia (Rhizobium tropici + R. freirei), Azospirillum brasilense, Anabaena cylindrica, and Calothrix brevissima, and application of 30 and 60 kg N kg ha−1 as topdressing in a factorial design. A control without N-mineral and inoculation was included. Co-inoculation of common bean (cv. IPR Curió) using A. cylindrica, C. brevissima with rhizobia, and A. brasilense, with the application of 30 kg N ha−1 in topdressing increases grain yields. Regardless of the growing season and the N dose, the dual inoculation of rhizobia and C. brevissima stood out in the increase of grain yield concerning the control without inoculation, showing that it is an efficient agronomic practice for common bean under tropical conditions.

Variation in Grain Mineral Concentrations of 63 Common Bean Genotypes Planted at Malkerns, Eswatini, in Africa

ABSTRACTLow soil mineral concentrations are a major limitation to the nutritional quality of grain crops produced in Africa. As a result, 232 million people are suffering from microelement deficiency and 239 million from protein‐calorie malnutrition in Africa. This study evaluated the nutritional quality of common bean grain harvested from 63 genotypes planted at Malkerns in Eswatini. The results showed significantly marked differences in the concentrations of 10 dietarily important nutrient elements. Of the macronutrients, Na levels showed the highest variation (12.00–91.00 mg/g) among the 63 bean genotypes, followed by K (14.03–22.03 mg/g) and P (3.30–9.57 mg/g), with Mg (1.57–2.30 mg/g) and Ca (0.80–2.68 mg/g) concentrations exhibiting the least difference among the bean genotypes. Of the micronutrients, Fe levels revealed the highest variation (66.36–151.08 mg/kg), followed by Zn (23.57–70.72 mg/kg) and Mn (11.53–26.84 mg/kg), with B (10.06–17.65 mg/kg) and Cu (6.30–13.67 mg/kg) exhibiting relatively lower differences among the 63 common bean genotypes. However, genotype NUC 461 recorded the highest grain concentrations of P, K, Mg, Fe, Cu, Zn, and B, followed by DAB 155, which also revealed high levels of P, K, Ca, Fe, Zn, and Mn in its seeds. For improved human health and nutrition, the two bean genotypes would be the ideal candidates to recommend to commercial bean growers and resource‐poor farmers. However, the mechanisms underlying the greater accumulation of six to seven dietarily important nutrient elements by genotypes NUC 461 and DAB 155 remain to be determined.

Determination of the Appropriate Blended Inorganic Fertilizer Rate Recommendation for the Optimal Common Bean (Phaseolus vulgaris L.) Grain Yield and Profitability in the Dawuro Zone, Ethiopia

Soil fertility decline is a significant factor affecting crop production. In a specific area, fertilizer application for a crop depends on soil type and profitability. Moreover, optimizing chemical fertilizer utilization in crop production is crucial from both environmental and economic perspectives. However, there is limited information available on the optimum NPSB fertilizer rate for common bean production in the study area. Thus, the study aimed to establish area-specific NPSB fertilizer rate recommendations for optimal grain yield and profitability of common bean. The field experiment was conducted in two locations in the 2019 and 2020 cropping seasons. The treatments included 0, 25, 50, 75, 100, 125, 150, 175, and 200 kg·ha−1 NPSB fertilizer rates, and they were planted using a randomized complete block design with three replications. The combined location analysis of variance indicated that the application of NPSB fertilizer significantly influenced plant height, number of pods per plant, number of seeds per pod, hundred-seed weight, biomass yield, grain yield, and harvest index. The highest grain yields (2815 kg·ha−1 and 3433 kg·ha−1) were recorded with the application of a 125 kg·ha−1 NPSB blended fertilizer rate, while the lowest grain yields (1429 kg·ha−1 and 1500 kg·ha−1) were produced from the nonfertilizer applied plot in Deneba and Wara, respectively. The combined location mean showed that the maximum grain yield (3124 kg·ha−1), followed by 2710 kg·ha−1, was produced by the application of 125 and 100 kg·ha−1 NPSB fertilizer rates, respectively. The data indicate that raising the NPSB fertilizer rate from 0 to 125 kg·ha−1 would greatly boost grain yield in the common bean in both locations in a similar manner. The economic analysis revealed that applying 125 kg·ha−1 of NPSB fertilizer earned the highest net benefits (140453.2 ETB·ha−1) with the highest marginal rate of return (1745.26%). Therefore, for high yield and profitability of common bean, a rate of 125 kg·ha−1 NPSB fertilizer is suggested in the study area and similar agro-ecological zones.

Protection of Stored Common Bean and Maize Grains Using Optimally Synthesized Biosilica from Rice Husk Ash

Losses provoked by insect pests on stored cereals and legumes contribute immensely to reduce food security, especially in rural communities in Sub‐Saharan Africa. The application of integrated control strategies, involving the use of synthetic pesticides, is often expensive and hazardous to humans and the environment. This study was conducted to optimize the production and use of biosilica from rice husk ashes, for the control of Sitophilus zeamais and Acanthoscelides obtectus, major insect pests of stored maize and common bean grains. The amorphous nature of the derived silica molecules coupled with the silanol and siloxane groups on their surfaces seemed to account for silica’s insecticidal effects on the pests, which were more on A. obtectus on common beans than S. zeamais on maize grains, with full mortalities obtained at doses of about 1.25 g per 50 g bean seeds and about 2.25 g per 50 g maize seeds, within 3 and 12 days, respectively. Similarly, the daily lethal dose (LD50) of silica powder required to obtain the mortality of half of the insects was lower on common beans than on maize seeds. The reduced phytotoxic activity of the biosilica on the stored common bean and maize grains indicates therefore that it could make an ecofriendly alternative to conventional protectants for small quantities of stored grains. However, large‐scale studies are needed in order to evaluate its potential use in grain storage systems.

Seleção de cultivares de feijão-comum em sistema de produção irrigado

ABSTRACT In irrigated production systems, the common bean grain yield must reach high levels to maintain economic viability. In this context, management, like the selection of the most adapted cultivars, may be effective in obtaining high yields. Through a three-year experiment, it was aimed to select the common bean cultivars with the highest agronomic and technological performance in an irrigated production system and to determine the yield component that most interfered with common bean yield. The treatments consisted of eight common bean cultivars with indeterminate growth habit and from the pinto bean variety (carioca): ANFc 9, BRS Estilo, BRSMG Madrepérola, Pérola, IAC Alvorada, IAC Milênio, TAA Bola Cheia, and TAA Dama. IAC Milênio and IAC Alvorada had the highest agronomic performance for irrigated production systems, with grain yields up to 17% higher than other cultivars. The cultivars show little variation in the grain technological quality, meeting the culinary and nutritional qualities recommended for common bean. The ANFc 9 cultivar showed the highest crude protein content in grains (19%). The number of pods per plant is the yield component that most interferes with common bean grain yield, generating 86 kg ha-1 increments for each unitary increase. Therefore, the common bean cultivars selection in the irrigated production system is an effective management practice to increase common bean agronomic and quality performance.

Mixture of winter cover crops improves soil physical properties under no-tillage system in a subtropical environment

The monocrop of winter cover crops is a common practice under no-tillage system (NTS) in subtropical environment but increase diversity of cover crop species can be an alternative to improve soil physical quality, with positive effects on crop production. This study evaluated whether using a greater diversity of cover crop species affects soil physical properties, as well as grain yield of soybean (Glycine max L.) and common bean (Phaseolus vulgaris L.) under NTS in three growing seasons. The experimental design was in randomized blocks with four replications. The treatments were monocrop of black oat (Avena strigosa Schreb.); intercropping of black oat and turnip (Brassica napus L.); and a mixture of black oat, turnip, white oat (Avena sativa L.), rye (Secale cereale L.), white lupine (Lupinus albus L.), and common vetch (Vicia sativa L.). Cover crop biomass yield, soil physical properties, and grain yield of summer crops were evaluated. Using a mixture of cover crops improved soil physical properties by decreasing soil bulk density up to 5 %, increasing soil air-filled porosity at –100 hPa (0.0–0.2 m) up to 27 % and saturated hydraulic conductivity (0.0–0.2 m) up to 300 %. Common bean grain yield and 1000-grain weight in succession to the mixture of cover crops increased by 15 % and 4 %, respectively. Soybean yield components were not affected by treatments. The increased diversity of winter cover crops improved soil physical properties in relation to monocrop in NTS, as well as improved crop yield of common bean, which is a shallower root growth specie, more sensitive to soil constraints.

Agronomic biofortification of common bean (Phaseolus vulgaris L.) cultivated in Oxisol with soil- and foliar-applied zinc

Consumption of foods with low zinc (Zn) contents has contributed to the onset of malnutrition and physiological problems in the population. Seeking to improve the nutritional quality of the grains, foliar applications of Zn have been carried out. The aim of this study was to evaluate Zn-EDTA and Zn-Amino as alternatives to ZnSO4, in foliar application, to improve the nutritional quality of the common bean cultivar ‘BRSMG Madrepérola’. An experiment was carried out in a greenhouse, in a factorial scheme [(3 × 5 + 1) + (1 × 3)], corresponding to three sources, five doses of foliar-applied Zn (2.5, 5.0, 10.0, 15.0 and 20.0 mg dm−3), one control, without Zn application and three doses of KCl (0.0, 0.2 and 0.4%) along with the 5 mg dm−3 dose of Zn, through foliar application of ZnSO4, in a randomized block design with four replicates. The foliar application of Zn-EDTA was found to be more effective than other sources in increasing the levels and quantities of zinc and other nutrients in common bean grains. Furthermore, increasing doses of Zn-EDTA resulted in lower phytotoxic effects in common beans when compared to doses of ZnSO4 and Zn-Amino, with only a minimal reduction in grain yield at the dosage that promoted higher zinc contents in the grains. The foliar application of different doses and sources of zinc leads to increased zinc contents in grains, which could help improve their quality and nutritional value for human consumption, reducing zinc malnutrition.

Pod positioning and grain yield of common bean as affected by sowing density, nitrogen fertilization and fertilization depth

The positioning of pods in common bean directly affects grain losses in mechanized harvesting. However, only few studies have assessed facttors that can affect pods positioning. The objective of this work was to determine the effect of plant density, nitrogen fertilization, and fertilization depth on the distribution of pods of the common bean. The field experiments were carried out in two cropping seasons, 2017 and 2018, during the winter period in the Cerrado region. The experimental design was randomized blocks in a 4x2 factorial scheme, with four replications. The treatments consisted of the combination of four sowing densities (5, 10, 15, and 20 plants m-1) with two depths of fertilizer application (6 and 12 cm). The results allowed inferring that the depth of the fertilization does not affect the distribution of pods in the common bean. Plant density does not affect common bean grain yield. More than a quarter of the common bean pods of the BRS FC104 are positioned close to the ground, below 100 mm, in the area where harvester machines operate. Nitrogen fertilization and plant density affect the distribution of pods in common bean plants. At higher doses of N (90 kg ha-1), plant density should be increased. On the other hand, at lower doses (45 kg ha-1), plant density must be reduced. It is concluded that the sowing density can be an efficient strategy to provide the highest positioning of pods in the upper part of the common bean plants, reducing harvest loss.

Wild sunflower interference in common bean fields in the Central Rift Valley of Ethiopia

AbstractThe wild sunflower, an invasive alien species, is known to affect the performance of field crops. A field experiment was conducted to estimate the effects of different levels of wild sunflower and common bean densities on common bean yield components and grain yield, as well as to quantify yield loss due to their competition at varying densities. The experiment was laid out in a randomized complete block design in a factorial arrangement with four replications. Hence, factorial combinations of three common bean densities and five wild sunflower densities were tested at two locations. At 24 plants m−2, wild sunflower had maximum dry biomass of 413.84 and 549.83 g−2 at Adamitulu and Melkassa, respectively. An increase in wild sunflower density from 0 to 24 plants m−2 resulted in a reduction of pods per plant up to 62.41% and 83.11%, respectively, at Adamitulu and Melkassa. Compared to the weed‐free plot, the highest wild sunflower density (24 plants m−2) had a 4.6‐fold reduction in seed per pod. Weed‐free plots at Adamitulu and Melkassa yielded the highest grain yields of 2.77 and 3.37 t ha−1, respectively. Common bean grain yield reduced by 88.12% and 67.64%, in Adamitulu and Melkassa, due to the highest density of wild sunflower. The rectangular hyperbolic equation fits common bean grain yields well. This study, hence, proposes that wild sunflower plants be kept at a density of no more than three plants per meter square to minimize severe yield loss and help common bean growers make decisions on wild sunflower control.

Genotype x environment interaction in the iron and zinc biofortification of common bean grains

Genotype x environment interaction in the iron and zinc biofortification of common bean grains

Sustainable production of biopesticides for common bean root rot control within the biorefinery approach: a Technology Readiness Level 3 experimental proof of concept.

Biopesticides are recognized as an efficient alternative to synthetic pesticides for pest and disease crop management. However, their commercial production processes use grains, generating large amounts of organic waste, even when agriculture waste or byproducts are the feedstock of choice. Frequently, these organic wastes are rich in nutrients that, after adequate treatment, can be used as nitrogen and carbohydrate sources for secondary metabolite production produced by microorganisms during submerged fermentation. In this sense, this study aimed to prove the concept that biopesticides could be produced under a full biorefinery process, using the entire biomass of an underexplored agroindustrial waste-damaged bean-as the main feedstock. A combination of sequential processes, including solid state fermentation, hydrolysis, and submerged fermentation, were designed for the production of two biopesticides (conventional-fungal conidia and second-generation secondary metabolite-cerulenin) from a high potential biological control agent strain Sarocladium oryzae BRM 59907. The combined processes, using damaged common bean grain as the main feedstock, provided biopesticides and organic fertilizer production that successfully controlled common bean root rot disease. This work proved to be possible the biopesticide production using a full biorefinery concept, inside the same productive chain, contributing to a sustainable environment and economy, together with animal and human health safety.

Genotype by environment interaction in common bean cultivars for iron and zinc concentration in grains

Iron and zinc deficiencies in humans can cause serious health problems. Increasing the iron (IC) and zinc (ZC) concentrations in common bean (Phaseolus vulgaris L.) grains using genetic breeding can be an effective strategy to prevent these problems. Thus, the aims of this study were i) to investigate the importance of genetic, environmental, and genotype-by-environment interaction effects on IC and ZC in common bean grains; ii) to select cultivars that have high mean values and phenotypic stability for IC and ZC, as well as high protein concentration (PC), high yield, and standard commercial grain quality; and iii) to investigate whether there is a genetic relationship between these traits. A total of 34 cultivars were evaluated in 19 different environments. Genetic variability was observed among the genotypes for all traits. For IC and ZC, the environmental effect represented most of the total variation (63% and 65%, respectively), and the effect of the G × E interaction was 18% for IC and 15% for ZC. The genetic correlations between IC, ZC, and PC were positive, indicating that the selection of one of these traits resulted in gains for the other. The genetic correlations between IC or ZC with yield or 100-grain weight were low or intermediate, but negative, indicating that it is important to evaluate these traits at all stages of breeding programs that focus on developing cultivars with high IC and ZC. The cultivar BRS Sublime, with the carioca grain type, combined high IC, ZC, and PC, high yield, and grains of commercial size.

Productivity of corn and beans as affected by season and source of nitrogen

Enhanced-efficiency fertilizers, which provide a reduction in nitrogen (N) losses, can be a viable alternative for the anticipation of topdressing for the moment of sowing, besides reducing operations for the rural producer. This study aimed to determine the effect of the period of application of enhanced-efficiency nitrogen fertilizers on the grain yield of corn and common bean in the Cerrado region in the direct seeding system. The experiment was carried out during two crop seasons (2019/2020 and 2020/2021), under field conditions. The completely randomized blocks experimental design was used, being arranged in a 2x4+1 factorial, with four replicates. Treatments consisted of the combination of the following two periods of nitrogen application: at sowing and recommended (four open leaves of corn and third trefoil in beans); and of the four following types of nitrogen fertilizers: 1. urea + NBPT + Zeolite; 2. urea + B + Cu + Zeolite; 3. Super N; and 4. Urea. Additionally, a control treatment (without N) was included. Nitrogen values for application in the treatments were adjusted so that 150 kg ha-1 N was applied to the corn, cultivated in summer, and 90 kg ha-1 N was applied to the common bean, cultivated in winter. It was concluded that nitrogen sources and period of nitrogen application did not affect corn grain yield, yield components, and common bean grain yield. The application of nitrogen in corn or common bean provided significant increases in crop grain yield.

The population density of Digitaria insularis influences Phaseolus vulgaris agronomic traits

The common bean (Phaseolus vulgaris L.) is an important species for human nutrition in Brazil and its cultivation has been hampered in recent years by the interference of sourgrass [Digitaria insularis (L.) Mez ex Ekman] populations. However, just a few studies evaluated sourgrass interaction with common beans. Therefore, we aimed to evaluate the influence of sourgrass density on common bean agronomic characteristics. Seven sourgrass densities, equivalent to populations from 0 to 12 plants m-², were established in a common bean crop field with a randomized block design and four replicates. The increase in sourgrass density boosted weed dry matter and the common bean plant’s height and leaf area index. Contrarily, the same increase in weed density reduced the crop chlorophyll content, stem diameter, shoot, root and total dry mass, and grain yield. The variables’ behavior testifies to the high sensitivity of the common bean to sourgrass interference reported by farmers. Variables such as common bean chlorophyll, stem diameter, and the shoot and root dry mass presented a strong negative correlation to the reduction in crop grain yield. The decrease in yield reached 69% with 12 sourgrass plants m-2 when compared to control. The density of 3.7 weed plants m-2 reduced the maximum common bean grain yield by half. Such significant results suggest the need for developing efficient sourgrass management methods and strategies to avoid common bean yield loss.

Agronomic biofortification increases concentrations of zinc and storage proteins in common bean (Phaseolus vulgaris L.) grains

Zinc (Zn) is an essential element for plants and mammals and its deficiency affects billions of people worldwide. This study aimed to evaluate the effects of soil Zn fertilization and foliar Zn sprays in different phenological stages of the plant on the grain nutritional quality of common bean (Phaseolus vulgaris L.). Field experiments were carried out in two consecutive harvest years under no-till system in an Oxisol. Two commercial common bean cultivars were used: BRS Esteio (black bean) and IPR Campos Gerais (Carioca bean). Total concentration of Zn, amino acids, sucrose, total sugars and storage proteins (albumin, globulin, glutelin and prolamin) in grains were evaluated. The cultivar BRS Esteio exhibited higher grain enrichment with Zn than the cultivar IPR Campos Gerais, showing genotypic variation. Single foliar Zn spray of 600 g ha−1 at the initial grain filling stage was shown to be the best way to improve the grain Zn concentration, without affecting grain yield. Foliar Zn spray at the final stage of grain filling favored the increase of Zn concentration in the pods over the Zn concentration in the grains. Agronomic biofortification of bean grains with Zn was more efficient with foliar Zn spraying than with the soil Zn fertilization, however, the soil Zn application favored the increase of concentrations of total amino acids and storage proteins (albumin, globulin and glutelin) in the grains. Agronomic biofortification proved to be efficient in increasing concentrations of Zn and storage proteins in common bean grains.

Selenium application methods and rates for biofortification of common bean and their residual effects on Mombaça grass

Context Agronomic biofortification is recognised as being an important strategy to increase selenium (Se) contents in food crops. The effectiveness of agronomic biofortification may differ depending on the methods of how Se is applied in agricultural systems. Aims This study aimed to evaluate different Se application methods (involving Se addition in the soil via Se-enriched fertilisers and foliar Se application) and rates for biofortification of common bean and to assess residual effects of soil Se additions for biofortification of Mombaça grass grown after the common bean. Methods Both experiments were carried out in a greenhouse. In the first cultivation (common bean), Se (as sodium selenate) was added at 0.0, 0.2, 0.4, 0.6, and 0.8 mg/dm3 using six different methods, as follows: Se-enriched monoammonium phosphate, Se-enriched urea, Se-foliar application, Se-enriched monoammonium phosphate + Se-enriched urea, Se-enriched monoammonium phosphate + Se-foliar application, and Se-enriched urea + Se-foliar application. To evaluate the residual effects of soil Se additions, Mombaça grass plants were grown after the common bean (second cultivation) without additional Se supply. Key results Agronomic biofortification effectiveness varied among methods, with higher Se contents in common bean grains being found when Se-enriched urea, Se-foliar application, and the combination of both methods were applied. Conclusions Selenium addition methods via soil using fertilisers as carriers to add Se, including Se-enriched monoammonium phosphate, showed a potential of residual effects on succeeding crops since these methods were efficient for increasing Se contents in Mombaça grass shoots.

Upland rice intercropped with green manures and its impact on the succession with common bean

AbstractThe aim of this work was to verify the possibility of intercropping rice with green manures, as well as the impact of the dry biomass yield of these intercropping systems on common bean in succession, evaluating the agronomic and qualitative performance of grains from both crops. The experiment was conducted in Southeastern Brazil in the years 2018 and 2019, with succession of rice (spring/summer) and common bean (autumn/winter). The treatments were composed of cropping systems with rice as a sole crop and intercropped with forage peanut, calopo, Crotalaria breviflora, Crotalaria spectabilis, stylo, jack bean and dwarf pigeon pea. No intercropping increased the system's yield compared to sole-crop rice, but intercropping of rice with forage peanut and stylo promoted grain yield and quality similar to those of sole-crop rice. Intercropping with C. breviflora affected the agronomic and qualitative performance of rice. Common bean yield after rice intercropped with dwarf pigeon pea, C. spectabilis and C. breviflora was similar in yield after sole-crop rice, while the other intercrops reduced common bean yield. Common bean grain quality was not affected by the cultivation of rice as sole crop and intercropped with green manures. Although none of the intercropping systems increased yield compared to sole-crop rice (control), it can be concluded that the intercropping of upland rice is viable depending on the green manure species, allowing greater biomass production per area that can help long-term soil conservation and increase the system's yield.

Biological nitrogen in increasing the productivity of beans (grains)

The results of a field experiment to study the effect of seed treatment with the biological product Rhizoactive (сompany BioNorma, Ukraine) on the formation and functioning of the symbiotic apparatus of common bean (grain) plants are presented.
 The experiment examined six varieties of common beans (grain), included in the State Register of plant varieties suitable for distribution in Ukraine: Bukovynka, Halaktyka, Slaviia, Ros, Otrada, Nata. The influence of bacterial fertilizer based on nodule bacteria " Rhizoactive " on the indicators of symbiotic and grain productivity of these varieties of common beans was studied.
 It was found, that the maximum number and raw weight of active nodules in the studied varieties of common beans were formed in the flowering phase. A larger number of nodules, compared to the variety Bukovynka (control), was formed on the root system of bean varieties Ros, Otrada and Nata. The maximum raw weight of rhizobia in the plots without the use of Rhizoactive was formed by the common bean variety Otrada – 0.297 g/plant of active nodules. Inoculation of the seeds of the studied common bean varieties with Rhizoactive increased the raw weight of active nodules in the flowering phase by 0.016–0.042 g/plant. A larger mass of nodules, compared to the Bukovynka variety, was formed on the root system of Ros, Otrada and Nata beans. The maximum raw weight of rhizobia in areas without the use of Rhizoactive was formed by the variety of beans Otrada – 0.297 g/plant of active nodules. Inoculation of seeds of the studied varieties of beans with Rhizoactive increased the raw weight of active nodules in the flowering phase by 0.016–0.042 g/plant.
 The highest increase in grain yield from seed inoculation was obtained in 2018, which was more favorable in terms of moisture. Thus, the largest increase in grain yield from the use of Rhizoactive was provided by the varieties Halaktyka (0.14 t/ha or 5.7 %), Ros (0.15 t/ha or 5.5 %) and Otrada (0.22 t/ha or 7.7 %). On average, in 2018–2020, inoculation of bean seeds with Rhizoactive, depending on the variety, provided an increase in grain yield from 2.4 to 6.7 %. And the highest level of bean grain yield on average in 2018–2020 was provided by the varieties Otrada (2.60 t/ha), Nata (2.50 t/ha) and Ros (2.40 t/ha) for inoculation of seeds with Rhizoactive

Selenium application influenced selenium biofortification and physiological traits in water-deficit common bean plants

Agronomic biofortification with selenium (Se) maybe employed to improve the nutritional value of food crops while increasing the plant’s tolerance to water deficit conditions. Although not essential for plants, Se may increase plant tolerance to water stress by boosting plants’ defence system activity. This study aimed to enrich common bean grains with Se and alleviate water deficit effects on common bean by applying Se to plants growing under greenhouse. Selenium was applied to soil at 0, 0.25, 0.5, 1.0, and 2.0 mg kg–1, under irrigated and water-deficit conditions. Antioxidant enzyme activities (SOD, CAT, and APX), H2O2 content, gas exchange, and SPAD index were assessed in plant leaves, and Se and nutrient concentrations were determined in grains. Results showed that water deficit decreased photosynthetic rate, stomatal conductance, transpiration rate, and increased water use efficiency. Selenium did not influence SPAD index in leaves from pod formation to maturity stage but improved the plant defence system by decreasing H2O2 content. Increasing Se rates increased Se concentration in grains and leaves. At lower Se rates, mainly at 0.25 mg Se kg–1, under water deficit, the activities of SOD, CAT, and APX reached their maximum values, and H2O2 content was minimum without reducing biomass production and nutrients accumulation. The highest Se rate (2 mg kg–1) was detrimental, since it decreased biomass production and the plant defence system under water deficit. Conclusively, soil Se addition enriched common bean plants with Se and showed positive responses against water deficit when applied at lower rates.

Grain quality of common bean cultivars under low and high nitrogen dose

This study aimed to evaluate the effects of low and high topdressing doses of nitrogen (N) on the qualitative attributes of common beans (Phaseolus vulgaris L.) cultivars and indicate cultivars with better grain technological characteristics. The experimental design was randomized blocks in split plots, with four replicates. Plots comprised 16 common bean cultivars of the commercial grain ‘Carioca’, while subplots comprised two N doses: 20 and 120 kg ha-1 applied as topdressing. The following evaluations were carried out: sieve yield (SY), relative grain production on sieves (RGPS), crude protein content (PROT), final water volume absorbed (FVabs), time for maximum hydration (TMH), hydration ratio (HR), cooking time (CT) and resistance to cooking (RC). The results were subjected to analysis of variance by F test and means were grouped by the Scott-Knott test. Multivariate principal component analysis was used to identify processes. The grain quality of common bean is more dependent on the genotype studied than on agricultural management such as nitrogen fertilization. The increase in the N dose applied as topdressing increases the size of common bean grains and their protein content, but with little influence in grain hydration. FVabs and CT depend on the interaction between cultivar and N doses. CT had an inverse correlation with PROT, but it was little pronounced. The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia have the best grain quality characteristics. Highlights: Cultivar interferes more in the common bean technological quality than nitrogen fertilization. Grains crude protein content had an inverse correlation with the cooking time. Nitrogen fertilization increases the grains size and crude protein content of common bean, but with little influence in grain hydration. The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia have the best grain quality characteristics.