Genotype × environment interaction in a national network of common bean trials across the three cropping seasons in Brazil

Nitrogen fertilizers are widely used on the cultivation of common bean in Brazil, affecting the production cost and the environment. Biological nitrogen fixation (BNF) can reduce the negative impacts related to N supply. This work aimed to evaluate the agroeconomic response of the inoculated common to N-fertilizer topdressing at different phenological phases of the common bean. N-fertilizer in a total of 90 kg ha−1 was applied in the form of urea at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. N-fertilizer splitting at any dose and phenological phase decreased NN and NDM. N-fertilizer treatments provided higher LAI and SDM compared with the inoculated treatment (P0V40R50). Inoculated treatment presented higher GY and lower PC, resulting in greater NR and BCR. Inoculation with Rhizobium tropici provided high nodulation to the common bean and increased its GY in 10.2% as compared with N-fertilization, which allowed a 15.8% and 7.8% higher NR and BCR, respectively, than the N-fertilized treatment.

Phaseolus vulgaris L. is the major pulse cultivated and culturally inculcated in the food habits of the locals in the Himalayan mountainous region of Azad Jammu and Kashmir (AJK), Pakistan. The current study was designed to investigate the role of P. vulgaris cultivation in providing livelihood support and to evaluate its production and consumption patterns correlated with the household variables in the state of AJK. The socio-economic data was collected from nine bean cultivated areas in six districts of AJK. The data was acquired by administrating a total of 522 detailed semi structured questionnaires from a diverse array of the respondents following the snowball technique focusing on yield, consumption, revenue generation and livelihood support provided by bean cultivation. The results revealed that common bean cultivation provided significant livelihood support to the local mountainous populations with an average annual income of 50.80 $/family. Subsequently, bean production contributed an average annual per capita income of 6.81 $ in the area, which was attributed to the large family size. Local populations showed an average bean production of 33.93 kg/family, whereas the average annual bean consumption was recorded as 31.99 kg/family in the region. Bean crops were recorded to have an average price of $1.49/kg, with significant variations in the study area correlated with local yield. A data analysis indicated a strong correlation in bean production and consumption patterns. Common bean farmers had a very small farm size, averaging 0.24 ha, where 100% of farmers cultivated common beans as an intercrop with Maize as the primary crop. A Pearson’s test (p value < 0.05) revealed significant correlations between land holding and bean production as well as consumption, and bean production with annual per capita income. Small farm size, declining soil fertility, low bean pricing and the unavailability of market mechanisms were identified as the major challenges faced by the common bean farmers. It is recommended to employ an integrated bean farming approach to enhance the economic impact of common bean cultivation in the socioeconomic appraisal of the local populations.

In recent years, common bean in Brazil has become interesting to precede the growing of off-season cotton due to its short cycle. This study was carried out in a Red Latosol in Chapadão do Sul, MS and aimed to select among the attributes of the evaluated soils, those with the best linear and spatial correlation, to explain the variability of grain yield of common bean in the soil layers of 0 - 0.10 m (layer 1) and 0.10 - 0.20 m (layer 2), sampled in a grid of 121 georeferenced points (spacing of 5 meters between points). The soil chemical attributes were determined: pH, carbon (C), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), and the sum of bases (SB). The analysis of these data was carried out using statistical and geostatistical techniques that made it possible to verify that for the grain yield of common bean, the multiple regression analysis indicates that approximately 20% of its variation is attributed to the variation in the chemical attributes of the soil presented in the present study. The chemical attributes pH1, pH2, C1, Ca1, Ca2, Mg1a, Mg2, Al2, SB1, and SB2 have spatial dependence classified mostly as moderate. Both linearly and spatially, C1 stood out as a potential indicator of common bean grain yield when grown under no-tillage.

The inoculation with Rhizobium together with nitrogen (N) fertilization during sowing can maximize common bean yield cultivated in the rainy season, but this interaction was not studied in the dry season cultivation. Therefore, the objective of this study was to evaluate the effects of biological nitrogen fixation (BNF) and or N fertilization on growth and yield of common bean cultivated in the dry season. Two experiments were conducted in a randomized block design with four replications. The first experiment, in 2013, had three treatments: F-25 (only fertilized with 20 kg of N ha-1 at sowing and with 40 kg of N ha-1 at 25 days after emergence - DAE), I-25 (only inoculated with Rhizobium tropici at sowing and fertilized with 40 kg N ha-1 at 25 DAE) and IF-25 (inoculated with R. tropici and fertilized with 20 kg N ha-1 at sowing and with 40 kg N ha‑1 at 25 DAE). The second experiment, in 2014, had the same three treatments and an additional treatment I (inoculated with R. tropici with no N fertilization). Three plants were collected randomly weekly, for growth analysis, which showed the highest biomass and leaf area accumulation and, consequently, highest grain yield of common bean in the treatment IF-25. The results indicated that in the dry season, the inoculation with Rhizobium tropici might replace the N fertilization (20 kg ha-1) at sowing without yield loss for common bean cultivation in a low-cost agriculture. Nevertheless, the N fertilization (20 kg ha-1) together with inoculation with Rhizobium tropici at sowing did not inhibit root nodulation, increasing growth and yield of common bean for a high-cost agriculture. However, more studies are required with other cultivars and sites, to recommend these agronomic practices in the cultivation of common bean in the dry season. &nbsp; Key words: Inoculation, fertilization, Rhizobium, Phaseolus vulgaris, growth.

Aphelenchoides besseyi is the causal agent of soybean green stem and foliar retention syndrome known as "Soja Louca II." This nematode has recently been reported parasitizing cotton in Brazil. In Costa Rica, it causes the symptoms known as "amachamiento" and false angular spots in common bean (Phaseolus vulgaris). Due to the great importance of beans to Brazilian agriculture, the objective of this research was to study the pathogenicity of A. besseyi in common bean under greenhouse conditions, including its endoparasitic relationships by staining root and shoot system tissues with fuchsin acid. In addition, A. besseyi was collected and quantified from shoot systems 30 days after inoculation by washing the tissue in water and blender centrifugal flotation. We observed the symptoms of amachamiento, leaf and vein deformation in the expanded trifoliate leaves, and also leaves with necrotic, brown to reddish and angular lesions, characteristics from false angular spot, and deformed stems characterized by enlargement of nodes, retortions, and necrotic lesions. High numbers of nematodes were found inside common bean plants. This is the first report of the pathogenicity and symptoms caused by A. besseyi in common bean in Brazil. These findings are important for development of management strategies to avoid losses on bean cropped in infested areas.

Enviromic prediction is useful to define the limits of climate adaptation: A case study of common bean in Brazil

Genetic progress during 22 years of improvement of carioca-type common bean in Brazil

The genetic structure of a population of Sclerotinia sclerotiorum causing white mold on common bean in Brazil was studied using microsatellite (SSR) loci and mycelial compatibility groups (MCGs). A total of 300 isolates were analyzed and 154 SSR haplotypes and 32 MCGs were identified. Two MCGs were widely distributed and accounted for 70% of the isolates. Six SSR haplotypes were associated with more than one closely related MCG. There was no evidence of random association of alleles among loci when the population comprised by all MCGs was analyzed, suggesting that outcrossing is absent or rare. Nevertheless, there was evidence of random mating within the major MCGs. Seven genetic groups were identified, one of them comprising only highly pigmented isolates. Isolates of distinct MCGs did not differ in virulence. There was strong genetic differentiation among MCGs: more than 95% of the total genetic variation was attributed to differences among these groups. Therefore, MCGs contribute to the structure of the population of S. sclerotiorum in Brazil.

When breeding the common bean in Brazil, the best progenies are chosen, normally, from solely the generation under analysis at the conclusion of the evaluation, without considering what occurred in the past. However, a number of recently published studies show that if an evaluation were to consider all relevant generations, the gain from selection could be higher, especially when an index that involves information from the population that gave rise to the progenies is used. Thus, the aim of this study was to compare three selection procedures in the evaluation of successive generations and to discuss the implications of the progeny × environment interaction in terms of success of selection. Cycle XV progenies from a bean recurrent selection program were used. The traits evaluated were grain yield, plant architecture and grain type. Analysis of variance was carried out and the variance components and heritabilities were estimated. The same analyses were made using mixed models. A selection index weighted by the effect of populations and progenies within populations (WSI) was also obtained. We estimated the correlations between the classification of the progenies using the three procedures and the coincidence of the best progenies evaluated in S0:4 with the progenies in the previous generations. We found that the classification of the progenies by the BLUP’s and WSI did not expressively differ from that obtained when using only the mean, even when a number of generations were considered in the selection. None of the procedures used effectively mitigated the effect of the progeny × environment interaction.

Common bean ( Phaseolus vulgaris L.) is among the most important food staples worldwide, mainly because of its relatively high protein content and other valuable nutritional qualities. Unfortunately, common beans are highly susceptible to plant viruses in general, including one of the largest families of plant viruses known as the Geminiviridae . These viruses, unlike most RNA plant viruses, possess a DNA genome that allows these pathogens to replicate in the nucleus of their plant host cells, thus, causing major damage to susceptible legume crops. Although some geminiviruses, belonging to two ( Mastrevirus and Curtovirus ) of the four genera that compose the Geminiviridae , can be transmitted by leafhoppers (Cicadellidae) to common bean, most geminiviruses that attack legumes belong to the genus Begomovirus , and are transmitted by the whitefly Bemisia tabaci (Genn.). In fact, the type species of this genus is bean golden yellow mosaic virus (BGYMV), which attacks over a million hectares of common bean grown in the lowlands and mid-altitude valleys of Central America, southern Mexico, the Caribbean region and northern South America. Another begomovirus, bean golden mosaic virus (BGMV), affects over two million hectares of common bean in Brazil, northern Argentina and the lowlands of Bolivia, in South America. In this region, bean dwarf mosaic virus (BDMV) has also caused the loss of thousands of hectares of highly valuable common bean genotypes in northwestern Argentina. In northwestern Mexico, thousands of hectares of common bean have been under the constant attack of a begomovirus related to a virus originally described in cucurbits, squash leaf curl virus (SLCV), in southwestern USA, currently known in Mexico as bean calico mosaic virus (BCaMV). Fortunately, none of these viruses is present in Eastern Africa, where the common bean is also a major food staple. Another Old World begomovirus reported to attack common bean both in the Old and New World, is tomato yellow leaf curl virus (TYLCV). This review describes the different breeding approaches followed since the 1970s to introduce resistance to begomoviruses infecting important legume crops, particularly common bean. This has been a challenging process, considering that no immune genotypes have been identified in more than 30000 common bean genotypes exposed to begomoviruses, such as BGMV or BGYMV.

Strategies for conserving natural resources and reducing agricultural inputs are the great challenge for agriculture, such as sustainable alternatives to control agricultural pests of high economic impact, e.g. plant-parasitic nematodes. This work aimed to evaluate phytonematode’s population dynamics in common bean cultivation grown under crop rotations and no-tillage system. The maize was seeded under pearl millet straw and intercropped with three different crops systems: i) exclusive maize system, ii) maize intercropped with brachiaria and, iii) maize intercropped with crotalaria. The experimental design was a randomized complete block with three treatments (crops systems) and 4 blocks (5 subsamples each block). The common bean was seeded on the straw of exclusive or intercropped maize. The phytonematode population was evaluated in the soil and in the roots in seven moments: (i) fallow; (ii) pearl millet flowering; (iii) pearl millet maturity; (iv) maize flowering; (v) maize maturity; (vi) common bean flowering; and (vii) common bean maturity. The greatest control of the phytonematodes species described in the area was in the maize intercropped with crotalaria treatment, as the phytonematodes population decreased 2.49-fold in this treatment when compared to exclusive maize, resulting in an increase of 11.27% in common bean yield. Therefore, maize intercropped with crotalaria is a viable alternative to reduce phytonematodes infestation in common bean crop.

White mold (Sclerotinia sclerotiorum) is a major problem of the common bean in Brazil. Thus, the objective of this study was to verify the effectiveness of chemical fungicides and biological products (Trichoderma spp) for the control of white mold in a bean field with different plant population densities located in the Silvânia, Goiás State, Brazil, in the 2007/08 rain season. The experimental design was the randomized blocks, with four replicates and seven treatments. The treatments are consisting of two levels of plant population densities (240 and 120 thousand plants/ha-1), chemical fungicides (carboxin-thiram and procymidone) and biological fungicides (Trichoderma spp), as well as untreated control. The results indicated that there was no significant interaction between bean population densities and chemical and biological fungicides applied to control S. sclerotiorum. The biological agent Trichoderma spp. is not effective in controlling S. sclerotiorum in common bean crop grown in the Brazilian “cerrado” region. Application of carboxin-thiram + procymidone was the most efficient treatment for the control of white mold on the common bean. Lower planting density is recommended for areas contaminated with S. sclerotiorum, as it can be easily associated with other control strategies.

Common bean is of great relevance for several countries, especially those located in tropical regions. Common bean in Brazil has a wide genetic diversity, which is used by breeders to improve this crop. In this study, we used GBS methodology to genotype common bean accessions from Northeast Brazil, and to study its population structure and genetic diversity. After a filtering process, we identified 30,529 high-quality SNPs distributed in 11 linkage groups. The number of SNPs per chromosome ranged from 1,731 to 3,853. The population structure analysis separated the accessions into two subpopulations, according to K=2, one subpopulation with 26 Andean and the other with 60 Middle American accessions. Considering K=3, Middle American accessions were divided into two subpopulations with presence of allele mixture between these two groups. Based on the PCA, we were able to verify a narrow genetic base of accessions belonging to the Andean gene pool, as well as a vast genetic diversity among the accessions from the Middle American gene pool. The knowledge on the genetic diversity among the accessions is of extreme importance to subsidize the common bean breeding programs in Northeast Brazil, and to explore the variability existing in cultivars adapted to the specific bioclimatic conditions.

Due to the socioeconomic importance of common bean in Brazil, studies that allow establishing favorable conditions for not compromising the crop with white mold, in view of the enormous damages caused by this fungus, become vital to Brazilian agriculture. Therefore, the aim of this study was to evaluate the incidence and severity of white mold in common bean (Phaseolus vulgaris L.), cultivar ‘Madrepérola’, subjected to different irrigation intervals, planting densities and fungicide application. The research was conducted in Viçosa-MG, Brazil, in the years 2011 and 2012. The statistical analysis used the split-split-plot scheme. The fungicide applications (with or without fungicide) were allocated to plots, the irrigation intervals (3, 6, 9 and 12 days) to sub-plots and planting densities (6, 9, 12 and 15 plants per linear meter) to sub-subplots, in a randomized block design with three replicates. The variation of the irrigation intervals did not contribute significantly to the control of white mold. It is recommended to use lower planting densities in order to minimize the damages caused by the disease. The use of the fungicide was the main method of white mold control in two consecutive years.

Native pollinators improve the quality and market value of common bean