Common Bean Yield Research Articles

Sink Strength Maintenance Underlies Drought Tolerance in Common Bean.

Drought is a major limiter of yield in common bean, decreasing food security for those who rely on it as an important source of protein. While drought can have large impacts on yield by reducing photosynthesis and therefore resources availability, source strength is not a reliable indicator of yield. One reason resource availability does not always translate to yield in common bean is because of a trait inherited from wild ancestors. Wild common bean halts growth and seed filling under drought and awaits better conditions to resume its developmental program. This trait has been carried into domesticated lines, where it can result in strong losses of yield in plants already producing pods and seeds, especially since many domesticated lines were bred to have a determinate growth habit. This limits the plants ability to produce another flush of flowers, even if the first set is aborted. However, some bred lines are able to maintain higher yields under drought through maintaining growth and seed filling rates even under water limitations, unlike their wild predecessors. We believe that maintenance of sink strength underlies this ability, since plants which fill seeds under drought maintain growth of sinks generally, and growth of sinks correlates strongly with yield. Sink strength is determined by a tissue’s ability to acquire resources, which in turn relies on resource uptake and metabolism in that tissue. Lines which achieve higher yields maintain higher resource uptake rates into seeds and overall higher partitioning efficiencies of total biomass to yield. Drought limits metabolism and resource uptake through the signaling molecule abscisic acid (ABA) and its downstream affects. Perhaps lines which maintain higher sink strength and therefore higher yields do so through decreased sensitivity to or production of ABA.

Potato peel alleviation of the negative effects of salinity in bean (Phaseolus vulgaris L. ‘Valentine’)

Soil salinity is a serious problem that negatively affects the productivity of plants. Reducing the impact of salinity to sustain production is a goal of scientists. The objective of this study was to determine the effect of potato peel amendments at different rates in reducing the negative impact of saline water. Common bean (Phaseolus vulgaris L. ‘Valentine’) was grown in soil mixed with potato peel at different rates (0%, 2.5%, 5%, and 7.5%). To achieve this objective, plants were irrigated with three levels of saline water (0, 50, and 100 mmol L−1) to induce stress at the vegetative stage. The results demonstrated the significant reduction in physiological parameters, plant growth, and yield of common bean after irrigation with saline water. Soil amendment with different rates of potato peel significantly increased the number of pods per plant, weight of pods per plant, pod length, chlorophyll content, and relative water content of common bean irrigated with saline water (50 mmol L−1) as compared with non-amended soil. Potato peel application also reduced electrolyte leakage and improved soil properties by reducing the salinity of the soil. Furthermore, among all potato peel rates used in this investigation, the 7.5% rate had a better result for common bean production. Conversely, potato peel did not improve the yield of beans grown under a high concentration of saline water (100 mmol L−1). In conclusion, soil amendments with potato peel at a 7.5% rate could be successfully used as a cost effective management practice to enhance bean production in soils stressed with high salt content.

Water use efficiency, grain yield, and economic benefits of common beans (Phaseolus vulgaris L.) under four soil tillage systems in Mukono District, Uganda

With the increasing climate change impacts and variabilities, water is becoming a limiting factor for rainfed crop production in Uganda. Conservation tillage practices could improve soil and water conservation in croplands. Field experiments were conducted for three consecutive seasons from April 2019 to June 2020. The experiments evaluated the effect of soil tillage treatments on soil water storage, water use efficiency, grain yield, and economic benefits of the common beans (Phaseolus vulgaris L.) in two sub-counties of Mukono District, central Uganda. The soil tillage treatments were: no-tillage, stubble-mulching, deep tillage, and conventional tillage. The no-tillage and stubble-mulching improved soil water storage by 46 and 45%, respectively, compared with the conventional tillage in the 0–100 cm soil depth over the 14 months. Soil tillage treatments significantly (p < 0.05) affected the water use efficiency, with water use efficiency values generally higher under no-tillage and stubble-mulching than under deep tillage and conventional tillage treatments. The grain yield was highest under no-tillage and stubble-mulching than deep tillage and conventional tillage treatments, with over 5, 38, and 43% higher grain yield under no-tillage than under stubble-mulching, deep tillage, and conventional tillage treatments, respectively. Although no-tillage and stubble-mulching improved soil water storage and grain yield, seasonal precipitation distribution had a greater influence on the final grain yield, soil water storage, and water use efficiency. The net profit was 3 and 5 times higher under no-tillage than under conventional tillage and deep tillage treatments, respectively. The overall results showed that no-tillage and stubble-mulching were the optimum tillage treatments for increasing soil water storage and common bean yield, enhancing water use efficiency, and improving economic returns in central Uganda.

English

Soil acidity and micronutrient deficiency is a major constraint affecting common bean production in Western Kenya. Farmers in the region have access to the two fertilizers Mavuno and Sympal fortified with different micronutrients and recommended for legumes; however, the performance of beans in the region remains low. A field experiment was, therefore, conducted in two sites in Nandi county, western Kenya, to determine the effect of using customized micronutrient fertilizer with lime on common bean yield. A factorial experiment was set up in a randomized complete block design consisting of three fertilizer types and lime treatments applied at two levels (0 and recommended rate). The fertilizer treatments were Mavuno (0 and 185 kg ha-1), Sympal (0 and 125 kg ha-1), Diammonium phosphate (0 and 62.5 kg ha-1) and lime (0 and 1.6 or 2.0 tons ha-1 depending on the lime requirement for the site). The experiment was run for two seasons, 2019 long and short rain seasons. Data were collected on nutrient uptake, crop growth and yield. The application of Mavuno fertilizer with lime significantly increased grain yield by 42, 30 and 27 % compared with control, Sympal and DAP, respectively. The application of Sympal and DAP did not have a significant effect on bean grain yield. Mavuno fertilizer with lime performed better in improving bean yield compared to the standard practice (DAP) and Sympal fertilizer. These results demonstrate the importance of using Mavuno fertilizer containing micronutrients Mo and B in combination with lime in improving legume production in Western Kenya. Key words: Common bean, customized fertilizer, lime, macronutrient, micronutrients, soil acidity.

Rare Earth Elements (REEs) Rich-Phosphate Fertilizers Used in Brazil are More Effective in Increasing Legume Crops Yield Than Their REEs-Poor Counterparts

Rare earths elements (REEs) can affect plant growth positively. Besides their intentional agricultural use, REEs have also been involuntarily applied to soils through phosphate (P) fertilizers. This study aimed to evaluate the effects of REEs contained in P fertilizers on increasing legume crops yield in Brazilian agroecosystems. Field experiments were conducted with Phaseolus vulgaris L. and Glycine max (L.) Merrill with four sources of P (a pure ammonium phosphate with no REEs and three single superphosphates—SSP—with varying REEs contents) applied to the soil at four P rates (0, 17.5, 35, 70 kg ha−1). Irrespectively of the rate, the SSP—Catalao (richest in total and soluble REEs among the sources tested) consistently increased the yield of common bean (~ 30%) in relation to the control (ammonium phosphate). Single superphosphate Araxa (intermediate REEs content) also increased common bean yield. For soybean, the SSP-Catalao, at the 70 kg P ha−1 rate, was superior to the control (at the same level of P) and to the treatment without P addition. Our results showed that the REEs, present as impurities in phosphate fertilizers, increase their effectiveness on legume crops yield. These findings are relevant, as producers could enhance yield with REEs-rich P-fertilizers, especially in tropical agroecosystems, where high application rates are required.

Allelic Diversity, Structural Analysis, and Genome-Wide Association Study (GWAS) for Yield and Related Traits Using Unexplored Common Bean (Phaseolus vulgaris L.) Germplasm From Western Himalayas.

The north-western Indian Himalayas possesses vast diversity in common bean germplasm due to several years of natural adaptation and farmer’s selection. Systematic efforts have been made for the first time for the characterization and use of this huge diversity for the identification of genes/quantitative trait loci (QTLs) for yield and yield-contributing traits in common bean in India. A core set of 96 diverse common bean genotypes was characterized using 91 genome-wide genomic and genic simple sequence repeat (SSR) markers. The study of genetic diversity led to the identification of 691 alleles ranging from 2 to 21 with an average of 7.59 alleles/locus. The gene diversity (expected heterozygosity, He) varied from 0.31 to 0.93 with an average of 0.73. As expected, the genic SSR markers detected less allelic diversity than the random genomic SSR markers. The traditional clustering and Bayesian clustering (structural analysis) analyses led to a clear cut separation of a core set of 96 genotypes into two distinct groups based on their gene pools (Mesoamerican and Andean genotypes). Genome-wide association mapping for pods/plant, seeds/pod, seed weight, and yield/plant led to the identification of 39 significant marker–trait associations (MTAs) including 15 major, 15 stable, and 13 both major and stable MTAs. Out of 39 MTAs detected, 29 were new MTAs reported for the first time, whereas the remaining 10 MTAs were already identified in earlier studies and therefore declared as validation of earlier results. A set of seven markers was such, which were found to be associated with multiple (two to four) different traits. The important MTAs will be used for common bean molecular breeding programs worldwide for enhancing common bean yield.

Grain yield of common bean (Phaseolus vulgaris) varieties depending upon the growing technology elements

Grain yield of common bean (Phaseolus vulgaris) varieties depending upon the growing technology elements

Silicate rocks as an alternative potassium fertilizer for upland rice and common bean crops

Abstract: The objective of this work was to evaluate the efficiency of molten and ground alkaline potassium-silicate rocks (K1) and of ground phonolite rock (K2) as sources of potassium for upland rice (Oryza sativa) and common bean (Phaseolus vulgaris) crops, in comparison with the traditional source (KCl). Two experiments - one with each crop - were conducted on a Typic Haplorthox in a randomized complete block design with four replicates. The treatments consisted of three sources (KCl, K1, and K2) and four rates (0, 20, 40, and 80 kg ha-1 K2O) of K. Regardless of the used source, K fertilization increased the leaf K content and grain yield of the upland rice and common bean crops. The agronomic efficiency index (AEI) of the alternative K sources varied according to the crop. For upland rice, the AEI of K2 was 8% higher than that of KCl at the recommended K rate, but similar at the highest rate. For common bean, the AEI values of K1 were close to that of KCl at the rates of 40 and 80 kg ha-1 K2O. The alternative sources K1 and K2 supply K and increase the grain yield of common bean and upland rice, respectively, similarly to KCl.

Alleviating of Lead toxicity using salicylic acid foliar spray in common bean (Phaseolus vulgaris L.) plant

This experiment consist of combination influence of salicylic&nbsp;&nbsp; &nbsp;acid and lead on common bean plants which conducted in greenhouse of Biology Department in the College of Science- University of Salahaddin- Erbil, with foliar application of Salicylic acid (SA) concentrations (0,100,200,400 ppm) and Lead (Pb) concentrations (0, 5, 10 ppm) on vegetative growth, yield and chemical components of common bean. The study consists of ten treatments with four replications. The following growth parameters were observed plant height, number of leaves, number of branches, dry weight of shoot system, water content leaf area, and yield characteristics such as pod number seed number dry weight of 100 seeds, and chemical contents and mineral contents of leaves. The results notices that SA significantly decreased the harmful effects of Pb on the vegetative growth characteristics such as height of plant number of leaves, number of branches, weight dry of shoot system, also on yield parameters such as number of seeds per pod, dry weight of 100 seeds and on chemical contents such as chlorophyll a and total chlorophyll contents, total protein content of leaves and total sodium.

SPATIAL CORRELATION BETWEEN THE CHEMICAL ATTRIBUTES OF A RED LATOSOL AND THE GRAIN YIELD OF COMMON BEAN

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.

Duration of Weed Presence Influences the Recovery of Photosynthetic Efficiency and Yield in Common Bean (Phaseolus vulgaris L.)

Photosynthetic responses of common bean (Phaseolus vulgaris L.) to increasing durations of weed-free and weedy environments were investigated using a critical period for weed control study under field conditions. The presence of weeds induced the shade avoidance response and was accompanied by a reduced red to far-red ratio (R/Fr) of reflected light supporting previous assertions it is an important signal regulating crop-weed interactions. Despite increases in stomatal conductance and leaf intercellular [CO2] with increasing duration of weed presence, CO2 assimilation and photosynthetic efficiency continually declined. This coincided with reduced Calvin cycle capacity suggesting induction of biochemical rather than stomatal limitations on photosynthesis. Weed removal prior to reproductive stages resulted in maintenance of high photosynthetic capacity. When weed presence extended to reproductive stages and beyond the critical period for weed control, however, CO2 assimilation and photosynthetic efficiency never recovered. Yield was highly correlated with photosynthetic efficiency and in a similar manner, declined with increasing durations of weed presence through reduced seeds per plant. We conclude that the lasting consequence of weed competition is impairment of photosynthesis, which may provide an important mechanism to explain yield loss.

Effects of Foliar Spraying with some Antioxidants on Growth, Dry Seed Yield and Chemical Constituents of Common Bean (Phaseouls vulgaris L.) Plants Grown under Water Stress Levels

The current study was carried out at Qaha Vegetable Research Farm (Qalubia Governorate), Horticulture Research Institute, Agriculture Research Center (A. R. C.), Egypt, during the two successive summer seasons of 2017 and 2018 on common bean cv Nebraska. The aim of this study was to investigate the effect of applied antioxidants (ascorbic acid at 100, 200 mg/L and putrescine at 25, 50 mg/L) under water regimes at three levels i.e. 100%. (control), 75% (moderate stress) and 50% (severe stress) of ETo(Evapotranspiration) respectively of water requirements of common bean plants in the two seasons and their interactions on vegetative growth characteristics, dry seed yield and its components and chemical compositions as well as seed quality. The experimental design was split-plot, the water regimes were arranged in the main plots, while foliar spraying with ascorbic acid and putrescine were adopted in the sub-plots. The obtained results of the treatments showed that foliar spraying with the aqueous solution of putrescine or ascorbic acid at the highest rate of 50 mg/ L or 200 mg/ L respectively under irrigated common bean plants with the moderate water level (75% ETo) markedly increased all of the vegetative growth parameters and dry seed yield and its components. In additions, the same mentioned treatments showed obvious increment in the chemical composition in leaves and dry seeds in both seasons. And led to save a part of the irrigation water (about 25 %) especially under the condition of water stress or drought

Arbuscular mycorrhizal fungi alter antifungal potential of lemongrass essential oil against Fusarium solani, causing root rot in common bean (Phaseolus vulgaris L.)

The variation in chemical composition of essential oils (EOs) as affected by plant phenology and environmental factors is a crucial limitation in standardization of EOs and thus their effective implementation into novel organic farming. The cultivation of medicinal and aromatic plants (MAP) using bio-elicitors has been advocated as genuine tool to sustainably assure higher quantity and quality EOs. Herein, a field trial and laboratory bioassays were undergone to decipher the impact of a local arbuscular mycorrhizal fungi (AMF) inoculation on agro-morphological yield, EO output and differential suppression of common bean (Phaseolus vulgaris L.) root rot incited by Fusarium solani. The field experiment was laid out following a completely randomized block design (CRBD) with two treatments; non-inoculated control and AMF-inoculation in triplicates. The effects of the EOs were tested against mycelial growth, conidia and common bean seeds germination. Promising concentrations were thereafter assessed for their suppressive effect against Fusariun solani in planta. A significantly higher collar diameter, hypocotyl branching and subsequent Mycorrhizal Dependency (MD) in mycorrhizal lemongrass [(+)AMF] compared to non-inoculated counterpart [(-)AMF]. The resulting EOs consistently repressed F. solani Fs4 conidia germination and mycelium deployment in a dose-dependent manner, with minimum inhibitory concentration (MIC) of 500 ppm for both the EOs, and 125 ppm for the reference fungicide (Ridomil Plus 44 WP). The EO from mycorrhizal lemongrass protected the common bean plantlets from infection by F. solani Fs4 both in laboratory and greenhouse conditions, leading to healthier and vigorous plantlets. The best protection rate was once more obtained with EO from AMF-primed lemongrass at the concentration of 1000 ppm (65.0%) while the lowest disease severity was obtained with Ridomil Plus 44 WP (63.13%). Overall, AMF inoculation shifted the lemongrass biochemical processes with subsequent impact on growth, and an enhanced suppression in Fusarium root rot under greenhouse conditions.

Vermicompost Application in Different Intercropping Patterns Improves the Mineral Nutrient Uptake and Essential Oil Compositions of Sweet Basil (Ocimum basilicum L.)

Only a few studies have hitherto investigated the effects of the application of organic fertilizers in intercropping systems on the plant essential oil (EO) productivity. Hence, this work has aimed to study the effect of different intercropping patterns on EO quality and quantity of sweet basil (Ocimum basilicum L.) under vermicompost application. In the present study, the cropping patterns consisted of 1B:1CB, 2B:2CB, 3B:2CB, and 4B:2CB (basil: common bean) as well as the pure culture of both crops and fertilizer treatments including usage or non-usage of vermicompost. The maximum seed yield of common bean (2786 kg ha−1) and dry matter yield of basil in the first (261.5 g m−2) and second harvests (214.7 g m−2) were recorded in the pure cultures fertilized with vermicompost. In addition, the nutrient uptake rate of macronutrients and micronutrients in both plants after application of vermicompost improved in intercropping patterns. In both harvests, the maximum EO content of basil (0.84% in the first harvest and 0.69% in the second harvest) was observed at the cropping ratio of 3B:2CB fertilized with vermicompost. Chemical analysis, achieved by GC–MS, evidenced 1,8-cineole, linalool, methyl chavicol, α-trans-bergamotene, methyl eugenol, and epi-α-cadinol as the main basil EO constituents in both harvests. The highest increment level for most ofEO constituents, nutrient uptake, and land equivalent ratio (1.52) were obtained in the intercropping pattern of 3B:2CB fertilized with vermicompost. In general, the intercropping pattern of 3B:2CB after use of vermicompost can improve the EO productivity and quality of basil. This intercropping pattern was accompanied by the increment of nutrient uptake. Therefore, this treatment can be introduced as a valid and sustainable strategy to replace chemical fertilizer and plant monoculture.

Genome-Wide Association Studies Detect Multiple QTLs for Productivity in Mesoamerican Diversity Panel of Common Bean Under Drought Stress.

Drought stress is an important abiotic factor limiting common bean yield, with great impact on the production worldwide. Understanding the genetic basis regulating beans’ yield and seed weight (SW) is a fundamental prerequisite for the development of superior cultivars. The main objectives of this work were to conduct genome-wide marker discovery by genotyping a Mesoamerican panel of common bean germplasm, containing cultivated and landrace accessions of broad origin, followed by the identification of genomic regions associated with productivity under two water regimes using different genome-wide association study (GWAS) approaches. A total of 11,870 markers were genotyped for the 339 genotypes, of which 3,213 were SilicoDArT and 8,657 SNPs derived from DArT and CaptureSeq. The estimated linkage disequilibrium extension, corrected for structure and relatedness (r2sv), was 98.63 and 124.18 kb for landraces and breeding lines, respectively. Germplasm was structured into landraces and lines/cultivars. We carried out GWASs for 100-SW and yield in field environments with and without water stress for 3 consecutive years, using single-, segment-, and gene-based models. Higher number of associations at high stringency was identified for the SW trait under irrigation, totaling ∼185 QTLs for both single- and segment-based, whereas gene-based GWASs showed ∼220 genomic regions containing ∼650 genes. For SW under drought, 18 QTLs were identified for single- and segment-based and 35 genes by gene-based GWASs. For yield, under irrigation, 25 associations were identified, whereas under drought the total was 10 using both approaches. In addition to the consistent associations detected across experiments, these GWAS approaches provided important complementary QTL information (∼221 QTLs; 650 genes; r2 from 0.01% to 32%). Several QTLs were mined within or near candidate genes playing significant role in productivity, providing better understanding of the genetic mechanisms underlying these traits and making available molecular tools to be used in marker-assisted breeding. The findings also allowed the identification of genetic material (germplasm) with better yield performance under drought, promising to a common bean breeding program. Finally, the availability of this highly diverse Mesoamerican panel is of great scientific value for the analysis of any relevant traits in common bean.

Application of Azospirillum on seeds and leaves, associated with Rhizobium inoculation, increases growth and yield of common bean.

Association of rhizobia with other plant growth-promoting bacteria (PGPB), such as Azospirillum, have the potential to increase crop yields. This work aimed to assess how Rhizobium tropici and Azospirillum brasilense alone or in combination, affect the growth and yields of common bean grains (Phaseolus vulgaris L.). In a field experiment, R. tropici and A. brasilense were inoculated on seeds, alone or in combination, associated or not with foliar spraying of A. brasilense. Shoot biomass, nitrogen accumulation, thousand-grain weight, and grain yield were evaluated. Application of A. brasilense, on seed or by foliar spraying, and seed inoculation of R. tropici, had an additive effect, increasing biomass and accumulated nitrogen, thousand-grain weight, and grain yield.

Straw Type and Nitrogen Fertilization Influence Winter Common Bean Yield and Quality

The common bean grown under straw of intercropped plants improves the cropping environment in no-tillage systems. In addition, nutrient supply from straw could reduce the use of topdressing nitrogen in common bean. Thus, the objective of this work was to evaluate under no-tillage system the effect of straw type and topdressing nitrogen doses in the irrigated common bean productive and qualitative attributes. The experimental design was in randomized blocks arranged in split-plots with four replications. The plots were composed by three straw types from different cropping systems, represented by sole maize, maize-intercropped with brachiaria and maize-intercropped with crotalaria. The subplots consisted of five topdressing N doses applied on common bean 0, 50, 100, 150 and 200 kg ha−1 of nitrogen via urea (coated with polymers). The common bean grown under the straw of maize intercropped with crotalaria showed higher number of pods per plant, grain yield and lower time for maximum grain hydration when compared to those plants grown under the straw of sole maize. Moreover, the crude protein content in the common bean grains was greater when plants were grown under the straw of maize intercropped with crotalaria than the straw of maize intercropped with brachiaria. The agronomic efficiency of common bean was higher when the plants were grown under the straw of maize intercropped with crotalaria in the lowest nitrogen fertilization rate tested (50 kg ha−1). Leaf nitrogen content, grain yield, sieve yield and crude protein content in the grain increased with increasing nitrogen availability via topdressing. Therefore, the results suggest that agronomic and qualitative characteristics of common bean are benefited when cultivated on the maize straw combined with crotalaria even reducing up to 50% the requirement of nitrogen fertilization.

Assessment of physiological traits of common bean cultivars in response to water stress and molybdenum levels

Molybdenum is an essential micronutrient that regulates plant growth, development, and responses to abiotic environmental stresses. However, little is known about the joint effects of water stress, molybdenum, and cultivar on physiological traits of field-grown common bean. Therefore, a split-plot factorial design was used to determine the main and interaction effects of Water stress (3 levels: 55–60, 90–95 and 120–125 mm evaporation from class A pan), Molybdenum (2 levels: control and 80 g per ha), and Cultivar (2 levels: Akhtar and COS-16) on physiological traits and grain yield of common bean. The results indicated that leaf area index (LAI), chlorophyll index, relative water content (RWC) and grain yield decrease with increasing water stress. Spraying molybdenum to the plants increased LAI, RWC, and grain yield, but the extent of the increase varied with cultivar. The positive effect of molybdenum also varied with the magnitude of water stress, and it was higher in severe water stress condition compared to that in normal irrigation and moderate water stress conditions. Of the two cultivars, COS-16 gave significantly higher grain yield than Akhtar cultivar, but Akhtar was superior in terms of physiological traits. The study demonstrated that the application of Molybdenum under water stress may cause an increase in N uptake and the efficiency of its use, that consequently increases the chlorophyll index and grain yield of common bean cultivars.

Management of plant architecture, spacing and population on the yield of super early common bean

For efficiency in the use of production factors and maximization of the yield of cultivars, it is essential to determine the most appropriate spatial arrangement for each cultivar and environment. This study identifies the effects of artificial adjustment of plant architecture, spacing between rows, and plant population on the yield of the super early common bean cultivar BRS FC104. We conducted the experiment in randomized blocks with subdivided plots and three replicates. In the plots, we assessed the spacing between rows (22.5, 45.0, and 67.5 cm). In the subplots, we considered the levels of artificial adjustment of plant architecture (maintenance of one or three lateral branches and control without architecture adjustment). In the subsubplots, we assessed populations of 6, 11, 16, and 21 plants per meter. The number of pods per plant increased with the increase in spacing between rows and with the reduction in plant population. Grain weight, in turn, increased with the reduction in spacing between rows and with the increase in plant population up to 14.7 plants per meter. Regarding grain yield and seed economy, the most suitable spatial arrangement for the super early cultivar consists of a 22.5 cm spacing between rows with about 12 plants per meter. The change in plant architecture, with the removal of lateral branches, is not effective to maximize yield.

Application of Response Surface Methodology in Optimization of the Yields of Common Bean ( Phaseolus vulgaris L.) Using Animal Manures

The objective of design and analysis of experiments is to optimize a response variable which is influenced by several independent variables. In agriculture, many statistical studies have focused on investigating the effect of application of organic manure on the yield and yield components of crops. However, many of these studies do not try to optimize the application of the manures for maximum productivity, but select the best treatment among the treatment range used. This is mainly due to design and analysis of experiments applied. Therefore, there is a need to apply a statistical method that would establish the effect of the application of organic manures on crop production and in addition optimize the levels of application of these manures for maximum productivity. This study aimed at application of response surface methodology for optimization of the yields of common bean (Phaseolus vulgaris L.) using animal manure. The study was conducted at Chuka University Horticultural Demonstration Farm. The experiment was laid down in a Randomized Complete Block Design. The treatments consisted of three organic manure sources (cattle manure, poultry manure and goat manure) each at three levels (0, 3 and 6 tonnes per ha). Data was collected from six weeks after sowing to physiological maturity. Data was collected on the weight of the grain yield harvested in each experimental plot measured by use of a weighing scale. The data collected was analysis using the R-statistical software. The study findings indicated that animal manures had a significant effect (p -1, 12.7213 t ha-1 and 4.1417 t ha-1 cattle manure, poultry manure and goat manure, respectively. These were the optimum levels that would lead to maximum yield of common beans without an extra cost of input.