Lima Bean Research Articles

Influence of NPK I5:15:15 fertilizer rates and vine training on profitability of Lima bean (Phaseolus lunatus L.) in Savanna zones, Nigeria

The study objective was to see how profitable it was to grow climbing bean cultivars with NPK 15:15:15 application rates in Nigeria's northern Guinea and Sudan Savanna zones. Field trials were done at the Institute for Agricultural Research Samaru, Ahmadu Bello University Zaria and National Horticultural Research Institute (NIHORT), Bagauda sub-station research farm throughout the 2018 wet season (from the final week of May as rain began to the last week of November).The treatments consisted of two cultivars of lima bean (Ex-Manchok Brown and Ex-Manchok Cream), training (trained and non-trained) and four levels of NPK 15:15:15 fertilizer rates (0, 150, 300 and 450 kg ha-1). The treatments were laid out in a randomized complete block design replicated three times. All lima bean production options were profitable at Samaru with trained Ex-Manchok Cream without fertilizer being most profitable (N476,858.4 ha-1) with net return of N 2.84 per naira invested. At Bagauda all production options were unprofitable due to low crop yields (105-237 kg ha-1): fertilizer and its application costs which accounted for 13.4 to 28.9% of total production cost in trained crop and 19.8 to 38.7% in non-trained. From this study it can be concluded that profitable and sustainable lima bean production, requires training of an adapted cultivar and application of 450 kg ha-1 of NPK 15:15:15 compound fertilizer.

Silicon assisted ameliorative effects of iron nanoparticles against cadmium stress: Attaining new equilibrium among physiochemical parameters, antioxidative machinery, and osmoregulators of Phaseolus lunatus

Currently, producing safe agricultural commodities from the crop plants cultivated in the soil with increasing heavy metal toxicity is a gigantic challenge in front of researchers. Heavy metals are absorbed and translocated in the crop plants and then transferred to every downstream consumer of the food chain, including humans, causing serious disorders and ailments. The current research presents a combined schematic application of iron nanoparticles (Fe-NPs) and/or silicon (Si), to mitigate cadmium (Cd) stress in Lima bean (Phaseolus lunatus). It was noted that Cd-induced toxicity curtailed growth, antioxidative machinery, glyoxalase system and nutrient uptake of the plants. Furthermore, the physiochemical features of Cd stressed plants, including carotenoids, chlorophyll, photochemical quenching, photosynthetic efficiency, and leaf relative water contents, were improved by the combined application of Si and Fe-NPs. Moreover, higher levels of malondialdehyde (MDA), methylglyoxal (MG), hydrogen peroxide (H2O2), and electrolyte leakage (EL) were observed in Cd stressed plants. Nevertheless, the independent treatment or combined application of Si and/or Fe-NPs attenuated the adversative effects of Cd on the aforementioned growth attributes. Furthermore, Si and Fe-NPs defended plants from the injurious effects of MG by improving the activities of the glyoxalase enzyme. The Si and Fe-NPs reduced Cd contents but at the same time improved uptake and accumulation of nutrients in treated plants exposed to the Cd regime. This study highlights that Si and Fe-NPs have enormous potential to mitigate Cd-induced phytotoxicity by declining Cd uptake and improving the growth attributes of plants if applied in combination.

SOCIOECONOMIC STATUS AND AGROFORESTRY READINESS: A CASE STUDY OF SELECTED COMMUNITIES IN THE OR TAMBO DISTRICT, EASTERN CAPE IN SOUTH AFRICA

This study pointed to the state of the community in terms of their socio-economic and agroforestry readiness in the OR Tambo District, which receives a median annual rainfall ranging between 800 and >1000 mm. In addition to favourable climatic conditions, the district has two plantations, namely the Mkambathi and Gqukunqa Forestry Enterprises, offering fertile ground to revive existing plantations, meaning that the community could immediately reap the benefits from the clear felling of the existing timber and agroforestry practices. Furthermore, the Agricultural Research Council conducted an assessment in collaboration with the Department of Agriculture, Land Reform and Rural Development aimed at identifying the community’s socio-economic status. Fifty-six community members from five local municipalities were selected, using a purposive sampling technique, and assessed. Quantitative and qualitative research designs were employed, as a structured questionnaire in English was developed, focus group and stakeholder discussions were held, as well as field observations to elicit information for the study. Data were coded, captured, and analysed using the Software Package for Social Sciences. The decantal 1km X 1km approach was followed to determine the climatic conditions of the two plantations. Currently, profitable and suitable crops like dry beans, sugar beans and groundnuts were recommended to the stakeholders for agroforestry integration. The study recommended the establishment of agroforestry in the OR Tambo District as it satisfied the basic requirements for agroforestry readiness, i.e. good climatic conditions, land availability, availability of production inputs and the community’s socio-economic status and involvement, towards food security.

Genetic diversity analysis of Lima bean (Phaseolus lunatus L.) Landrace from Ethiopia as reveled by ISSR marker

Lima bean (Phaseolus lunatus L.) is one of the five most important legume crops from the genus Phaseolus though it is one of the neglected crops in Ethiopia. There is no national breeding program for its improvement. As it is true for all crops, understanding the genetic diversity of Lima bean is useful for its improvement and sustainable use. Therefore, the objective of the current study was to investigate genetic diversity of Lima bean landrace collected in Ethiopia using eight issr markers. A total of 96 landrace were collected from five administrative zones of Ethiopia from which 106 clear bands were detected. About 95 (88.7%) of the bands were polymorphic. The genetic diversity analyses result revealed that landrace collected from West Wellega showed the highest (0.1864) genetic diversity. amova demonstrated highly significant (P=0.00) genetic diversity among and within populations. A considerable proportion (66%) of the total genetic diversity was distributed among populations and 34% within populations. In addition, the calculated Fst value was high (Fst = 0.66), associated with a low gene flow value (Nm=0.27) indicating lower differentiation of the populations, which, in turn, implied no significant exchange of planting materials among farmers in the studied populations and the nature of the crops that Lima bean is 52% self pollinated crop. upgma, structure and PCoA analysis showed very strong grouping among individuals collected from the same zones and geographically distinct zones. Overall, genetic diversity achieved from this study could be used as pioneer information about the existing genetic resource for future Lima bean conservation and improvement strategy in Ethiopia.

DECISION TREE AS A TOOL IN THE CLASSIFICATION OF LIMA BEAN ACCESSIONS

ABSTRACT Morpho-agronomic characterization studies aiming at the discrimination and classification of lima bean accessions in relation to the centers of domestication and biological status have been of great importance for conserving the biodiversity of this species. For this purpose, researchers have widely used the multivariate analysis called discriminant analysis, which is not always capable of producing satisfactory results. Computational intelligence-based classifiers are additional tools for understanding complex classification problems. In this study, the objective was to test the use of the decision tree in the classification of lima bean according to the centers of domestication and biological status (cultivated and wild), based on eight phenotypic traits of the seed. Sixty accessions of lima bean from the Phaseolus Germplasm Bank of Universidade Federal do Piauí (BGP / UFPI) were evaluated, and classification was performed using two approaches: conventional statistics with discriminant analysis of principal components (DAPC) and computational intelligence through decision tree (DT). The results showed that the use of DT was efficient to identify patterns in the classification of lima bean accessions, due to its comprehensibility. Seed weight was one of the main descriptors used to explain the origin and diversity of the species. The results found will be useful for studies that involve the conservation of genetic resources, mainly for the maintenance of germplasm banks and in breeding programs. In addition, it is recommended to integrate machine learning algorithms in studies aimed at classifying lima bean.

Diversity of Phaseolus lunatus L. in East Java, Indonesia based on PCR-RAPD technique

Diversity of Phaseolus lunatus L. in East Java, Indonesia based on PCR-RAPD technique

Antagonism of Trichoderma on the control of Fusarium spp. on Phaseolus lunatus L.

Biological control strategies have become an important tool in the sustainable management of plant diseases. This paper aims to report the Fusarium species that affect fava beans (Phaseolus lunatus L.) grown in Paraíba, Brazil, and determines the potential of Trichoderma isolates to control these fungi. Two Trichoderma and ten Fusarium isolates from fava bean seeds were selected. The beans were obtained from cultivated areas in the municipalities of Remígio, Alagoa Grande and Campina Grande, in Paraíba state. Phylogenetic analyzes based on DNA sequences of the translation elongation factor 1-α (TEF1) gene resolved the Fusarium isolates into four species belonging to the F. fujikuroi and F. incarnatum-equiseti species complexes. In vitro tests showed that the two isolates of Trichoderma tested presented antagonistic potential against the pathogens from the fava beans evaluated. In the direct comparison test, the growth of the pathogens was reduced from the seventh day in both treatments. Sporulation also showed a reduction, but only for 40% of Fusarium isolates. This work demonstrates that Trichoderma isolates can be used as a sustainable alternative to manage Fusarium spp. infection of fava beans.

DYNAMICS OF SOIL CARBON AND N, P, K NUTRIENTS ON CORN PLANTING PATTERN IN DRY LAND

A study was conducted during two planting seasons, namely planting season 1 (PS-1) 2017/2018 and (PS-2): 2018/2019, in Oelnasi Village, Central Kupang sub-district, Kupang District, East Nusa Tenggara, Indonesia. This study aimed to evaluate the rotation pattern of maize with legumes ground covers towards the dynamics of soil carbon and nutrients N, P, K during the two growing seasons in a dryland farming system. The experiment was designed using a randomized block design with 3 (three) treatments replicated five times. The treatments evaluated were: crop rotation patterns consisting of: without rotation (farmer practice) and rotation pattern with Phaseolus lunatus; rotation pattern with Mucuna pruriens. Legume crops planted after harvesting the food crop and allowed to grow during the dry season. Approaching the rainy season, the biomass of the legume crop is returned to the land by immersing them it together with soil cultivation. Chemical fertilizers is given as an independent variables with a dose of 150 kg/ha of Urea; 100 kg/ha of SP36 and 100 kg/ha of KCL. The results showed that the rotation pattern of Mucuna pruriens significantly increased the soil organic C content by 50.56% and legume Phaseolus lunatus by 37.64% to PS-2. The rotation pattern of the legume covers / covered crop also significantly increased the efficiency of agronomic nutrients (N, P, and K nutrients) and maize yields during the two growing seasons. On the other hand, the farmer pattern (without rotation) showed a decrease in soil carbon to PS-2 which of course affect the efficiency of nutrient absorption.

Gene Flow in Phaseolus Beans and Its Role as a Plausible Driver of Ecological Fitness and Expansion of Cultigens

The genusPhaseolus, native to the Americas, is composed of more than eighty wild species, five of which were domesticated in pre-Columbian times. Since the beginning of domestication events in this genus, ample opportunities for gene flow with wild relatives have existed. The present work reviews the extent of gene flow in the genusPhaseolusin primary and secondary areas of domestication with the aim of illustrating how this evolutionary force may have conditioned ecological fitness and the widespread adoption of cultigens. We focus on the biological bases of gene flow in the genusPhaseolusfrom a spatial and time perspective, the dynamics of wild-weedy-crop complexes in the common bean and the Lima bean, the two most important domesticated species of the genus, and the usefulness of genomic tools to detect inter and intraspecific introgression events. In this review we discuss the reproductive strategies of severalPhaseolusspecies, the factors that may favor outcrossing rates and evidence suggesting that interspecific gene flow may increase ecological fitness of wild populations. We also show that wild-weedy-crop complexes generate genetic diversity over which farmers are able to select and expand their cultigens outside primary areas of domestication. Ultimately, we argue that more studies are needed on the reproductive biology of the genusPhaseolussince for most species breeding systems are largely unknown. We also argue that there is an urgent need to preserve wild-weedy-crop complexes and characterize the genetic diversity generated by them, in particular the genome-wide effects of introgressions and their value for breeding programs. Recent technological advances in genomics, coupled with agronomic characterizations, may make a large contribution.

Dispensing a Synthetic Green Leaf Volatile to Two Plant Species in a Common Garden Differentially Alters Physiological Responses and Herbivory

Herbivore-induced plant volatile (HIPV)-mediated eavesdropping by plants is a well-documented, inducible phenomenon that has practical agronomic applications for enhancing plant defense and pest management. However, as with any inducible phenomenon, responding to volatile cues may incur physiological and ecological costs that limit plant productivity. In a common garden experiment, we tested the hypothesis that exposure to a single HIPV would decrease herbivore damage at the cost of reduced plant growth and reproduction. Lima bean (Phaseolus lunatus) and pepper (Capsicum annuum) plants were exposed to a persistent, low dose (~10 ng/h) of the green leaf volatile cis-3-hexenyl acetate (z3HAC), which is a HIPV and damage-associated volatile. z3HAC-treated pepper plants were shorter, had less aboveground and belowground biomass, and produced fewer flowers and fruits relative to controls, while z3HAC-treated lima bean plants were taller and produced more leaves and flowers than did controls. Natural herbivory was reduced in z3HAC-exposed lima bean plants, but not in pepper. Cyanogenic potential, a putative direct defense mechanism in lima bean, was lower in young z3HAC-exposed leaves, suggesting a growth–defense tradeoff from z3HAC exposure alone. Plant species-specific responses to an identical volatile cue have important implications for agronomic costs and benefits of volatile-mediated interplant communication under field conditions.

Antidiabetic Potential of Protein Hydrolysates and Peptide Fractions from Lima Bean (Phaseolus lunatus L): An In Vitro Study

Antidiabetic Potential of Protein Hydrolysates and Peptide Fractions from Lima Bean (Phaseolus lunatus L): An In Vitro Study

Common bacterial blight of bean: a model of seed transmission and pathological convergence.

Background Xanthomonas citri pv. fuscans (Xcf) and Xanthomonas phaseoli pv. phaseoli (Xpp) are the causal agents of common bacterial blight of bean (CBB), an important disease worldwide that remains difficult to control. These pathogens belong to distinct species within the Xanthomonas genus and have undergone a dynamic evolutionary history including the horizontal transfer of genes encoding factors probably involved in adaptation to and pathogenicity on common bean. Seed transmission is a key point of the CBB disease cycle, favouring both vertical transmission of the pathogen and worldwide distribution of the disease through global seed trade.TaxonomyKingdom: Bacteria; phylum: Proteobacteria; class: Gammaproteobacteria; order: Lysobacterales (also known as Xanthomonadales); family: Lysobacteraceae (also known as Xanthomonadaceae); genus: Xanthomonas; species: X. citri pv. fuscans and X. phaseoli pv. phaseoli (Xcf‐Xpp).Host rangeThe main host of Xcf‐Xpp is the common bean (Phaseolus vulgaris). Lima bean (Phaseolus lunatus) and members of the Vigna genus (Vigna aconitifolia, Vigna angularis, Vigna mungo, Vigna radiata, and Vigna umbellata) are also natural hosts of Xcf‐Xpp. Natural occurrence of Xcf‐Xpp has been reported for a handful of other legumes such as Calopogonium sp., Pueraria sp., pea (Pisum sativum), Lablab purpureus, Macroptilium lathyroides, and Strophostyles helvola. There are conflicting reports concerning the natural occurrence of CBB agents on tepary bean (Phaseolus acutifolius) and cowpea (Vigna unguiculata subsp. unguiculata).SymptomsCBB symptoms occur on all aerial parts of beans, that is, seedlings, leaves, stems, pods, and seeds. Symptoms initially appear as water‐soaked spots evolving into necrosis on leaves, pustules on pods, and cankers on twigs. In severe infections, defoliation and wilting may occur.DistributionCBB is distributed worldwide, meaning that it is frequently encountered in most places where bean is cultivated in the Americas, Asia, Africa, and Oceania, except for arid tropical areas. Xcf‐Xpp are regulated nonquarantine pathogens in Europe and are listed in the A2 list by the European and Mediterranean Plant Protection Organization (EPPO).GenomeThe genome consists of a single circular chromosome plus one to four extrachromosomal plasmids of various sizes, for a total mean size of 5.27 Mb with 64.7% GC content and an average predicted number of 4,181 coding sequences.Disease controlManagement of CBB is based on integrated approaches that comprise measures aimed at avoiding Xcf‐Xpp introduction through infected seeds, cultural practices to limit Xcf‐Xpp survival between host crops, whenever possible the use of tolerant or resistant bean genotypes, and chemical treatments, mainly restricted to copper compounds. The use of pathogen‐free seeds is essential in an effective management strategy and requires appropriate sampling, detection, and identification methods.Useful websites https://gd.eppo.int/taxon/XANTPH, https://gd.eppo.int/taxon/XANTFF, and http://www.cost.eu/COST_Actions/ca/CA16107.

미국 현대극 실험의 청사진: 인간 마네킹의 자유시 대화극 Lima Beans

Alfred Kreymborg was a bohemian intellectual in Greenwich Village, New York City, at the beginning of the 20th century. He experimented with a poetic experiment called ‘free-verse dialogue’ that was not bound by the traditional set-form poetry writing, which developed into an experiment on prose poem, and ultimately the writing of Lima Beans (1919). This one-act play has a simple plot depicting the daily life of a newlywed couple on their second week of marriage. The stage experiment requites more attention than the plot or story development in the play. Lima Beans is a short play piece that combines a new playwriting technique of ‘free-verse dialogue’ and a theatrical experiment called ‘a play with puppets.’ In the play, a couple of human mannequins dismantle traditional language and poetic practices while uttering fragments of words in staccato fashion. Their action and movement are jerky, wooden, and exaggerated. The stage set is surrounded by the black and white and cubist pastiche of geometric pattern, which reproduces a fanciful but abstract middle-class home. The whole picture woven with the setting, characters, and language of this play presents a blueprint for the new trends, non-realistic theatrical experiment, that would be attempted by the Provincetown Players, especially starting with Eugene O’Neill.

Replacing fishmeal with pretreated Lima bean improves growth, feed utilization, whole-body composition and nutrient retention in Nile-tilapia fingerlings

ABSTRACT The present study aimed to assess the effect of replacing fishmeal (FM) with soaked, cooked Lima bean meal (LBM) on growth, feed utilization, body composition and nutrient retention in Nile tilapia fingerlings, weighing 3.63 ± 0.81 g. Fingerlings (375) were randomly divided into five treatments and fed a commercial feed (CF), a control diet (D0) and three experimental diets (D25, D50 and D75) where FM was replaced by LBM at 25%, 50% and 75%. The results obtained with CF, D25 and D50 indicate significant variations in weight gain (52.71 ± 3.42 g, 35.01 ± 2.01 g and 35.89 ± 3.06 g), specific growth rate (4.02 ± 0.12%g/d, 3.42 ± 0.08%g/d and 3.41 ± 0.13%g/d), feed conversion ratio (1.14 ± 0.03, 1.73 ± 0.10 and 1.71 ± 0.14), compared to D0 (28.32 ± 0.93 g, 3.13 ± 0.09%g/d and 2.16 ± 0.06). The same observations were noted with regards to the body composition of proteins, lipids and ashes as well as their retention, compared to D0. These results indicate that LBM, when appropriately treated can replace FM up to 50% in formulating feed for Nile tilapia.

Changes in Microbial and Functional Properties of Lima Bean (Phaseolus lunatus) Flour During Storage

Lima bean is a nutritious food legume. In addition to nutritional value of food product, its keeping quality and functional properties during storage are also important in determining the quality of the food for consumption. The study aimed at evaluating the microbial and functional properties of lima bean flour during storage. Lima bean was processed into flour, packaged in low density polyethylene bag and stored at ambient (28 ± 2 o C) temperature for twenty-four weeks. The stored samples were evaluated for microbial (Total viable count and mold count) and functional properties (Bulk density, water and oil absorption capacity, foaming capacity, emulsion capacity and dispersibility). Total viable count (TVC) increased from 1.60 log cfu/g at week 0 to 4.25 log cfu/g at week 24 of storage. There was no mold growth till week 12 of storage. Mold count increased from 1.77 log cfu/g in week 12 to 3.77 log cfu/g in week 24. Both TVC and mold counts in the lima flour were far lower than the recommended limit of 10 6 cfu/g for TVC and 10 3 cfu/g for mold count respectively by International Microbiological Standards. There was no significant difference (p>0.05) in the bulk density of the lima bean flour at storage. Water absorption capacity, oil absorption capacity, foam capacity, emulsion capacity and dispersibility decreased slightly with storage time. The study showed that lima bean flour is safe for consumption and can serve as a potential functional food ingredient in food products formulation without much changes in its functional properties over a period of twenty-four weeks. Keywords: Lima bean flour, Functional properties, microbial properties, storage, safety. DOI: 10.7176/FSQM/107-05 Publication date: April 30 th 2021

Productivity of Lima Bean (Phaseolus Lunatus L.) Cultivars Using NPK Compound Fertilizer Rates and Training Practice in the Nigerian Savanna

Lima bean (Phaseolus lunatus L.) is a legume crop grown for its edible beans. The objective of this study was to determine the optimal rate of NPK fertilizer and the need for training to achieve the maximum yield of lima bean cultivars in the Nigerian Savanna. Field trials were performed at the research farm of Institute for Agricultural Research Samaru, Ahmadu Bello University Zaria and National Horticultural Research Institute (NIHORT), Bagauda sub-station during the wet season of 2018 (Duration month-month). The treatment consisted of two lima bean cultivars (Ex-Manchok Brown and Ex-Manchok Cream), preparation (trained and untrained) and four fertilizer levels of NPK 15:15:15 (control, 150, 300, and 450 kg ha-1). The treatments were laid out in a randomized complete block design replicated three times. Data showed that in Bagauda, Ex-Manchok Brown gave significantly higher in LAI at 6 WAS than Ex-Manchok Cream, while Ex-Manchok Brown outperformed in the number of seeds pod-1, 100-seed weight and seed yield ha-1 at Samaru Ex-Manchok Cream. Trained lima bean at Samaru resulted in significantly higher LAI at 9 WAS and branch numbers at 12 WAS, while 100-seed weight and seed yield ha-1 at Bagauda were significantly higher with vine training. NPK The application of 450 kg ha-1 in Samaru and Bagauda resulted in the highest seed yield. The outcome of this study verified that training with 9 DAS and 450 kg ha-1 of NPK 15:15:15 compound fertilizer is needed to obtain a maximum of Ex-Manchok Cream lima bean cultivar in Nigerian savanna beans.

Chloroplast genome sequence of Chongming lima bean (Phaseolus lunatus L.) and comparative analyses with other legume chloroplast genomes

BackgroundLima bean (Phaseolus lunatus L.) is a member of subfamily Phaseolinae belonging to the family Leguminosae and an important source of plant proteins for the human diet. As we all know, lima beans have important economic value and great diversity. However, our knowledge of the chloroplast genome level of lima beans is limited.ResultsThe chloroplast genome of lima bean was obtained by Illumina sequencing technology for the first time. The Cp genome with a length of 150,902 bp, including a pair of inverted repeats (IRA and IRB 26543 bp each), a large single-copy (LSC 80218 bp) and a small single-copy region (SSC 17598 bp). In total, 124 unique genes including 82 protein-coding genes, 34 tRNA genes, and 8 rRNA genes were identified in the P. lunatus Cp genome. A total of 61 long repeats and 290 SSRs were detected in the lima bean Cp genome. It has a typical 50 kb inversion of the Leguminosae family and an 70 kb inversion to subtribe Phaseolinae. rpl16, accD, petB, rsp16, clpP, ndhA, ndhF and ycf1 genes in coding regions was found significant variation, the intergenic regions of trnk-rbcL, rbcL-atpB, ndhJ-rps4, psbD-rpoB, atpI-atpA, atpA-accD, accD-psbJ, psbE-psbB, rsp11-rsp19, ndhF-ccsA was found in a high degree of divergence. A phylogenetic analysis showed that P. lunatus appears to be more closely related to P. vulgaris, V.unguiculata and V. radiata.ConclusionsThe characteristics of the lima bean Cp genome was identified for the first time, these results will provide useful insights for species identification, evolutionary studies and molecular biology research.

Lima Bean Growth, Leaf Stomatal and Nonstomatal Limitations to Photosynthesis, and 13C Discrimination in Response to Saline Irrigation

Soil salinization is a widespread problem severely impacting crop production. Understanding how salt stress affects growth-controlling photosynthetic performance is essential for improving crop salt tolerance and alleviating the salt impact. Lima bean (Phaseolus lunatus) is an important crop, but little information is available on its growth and leaf gas exchange in relation to a wide range of salinity. In this study, the responses of leaf gas exchange and whole plant growth of lima bean (cv. Fordhook 242) to six salinities with electrical conductivity (EC) of 2.9 (control), 5.7, 7.8, 10.0, 13.0, and 15.5 dS·m−1 in irrigation waters were assessed. Significant linear reduction by increasing salinity was observed on plant biomass, bean yield, and leaf net carbon assimilation rate (A). As EC increased from the control to 15.5 dS·m−1, plant biomass and A decreased by 87% and 69%, respectively, at the vegetative growth stage, and by 96% and 83%, respectively, at the pod growth stage, and bean yield decreased by 98%. Judged by the linear relations, the reduction in A accounted for a large portion of the growth reduction and bean yield loss. Salinity also had a significantly negative and linear effect on leaf stomatal conductance (gS). Leaf intercellular CO2 concentration (Ci) and leaf C13 isotope discrimination (Δ13) declined in parallel significantly with increasing salinity. The A-Ci curve analysis revealed that stomatal limitation [Lg (percent)] to A increased significantly and linearly, from 18% to 78% and from 22% to 87% at the vegetative and pod-filling stages, respectively, as EC increased from the control to the highest level. Thus, relatively nonstomatal or biochemical limitation [Lm (percent), Lm = 100 − Lg] to A responded negatively to increasing salinity. This result is coincident with the observed Δ13 salt-response trend. Furthermore, leaf carboxylation efficiency and CO2-saturated photosynthetic capacity [maximum A (Amax)] were unaffected by increasing salinity. Our results strongly indicate that the reduction in lima bean A by salt stress was mainly due to stomatal limitation and biochemical properties for photosynthesis might not be impaired. Because stomatal limitation reduces A exactly from lowering CO2 availability to leaves, increasing CO2 supply with an elevated CO2 concentration may raise A of the salt-stressed lima bean leaves and alleviate the salt impact. This is supported by our finding that the external CO2 concentration for 50% of Amax increased significantly and linearly with increasing salinity at the both growth stages. Leaf water use efficiency showed an increasing trend and no evident decline in leaf chlorophyll soil plant analysis development (SPAD) readings was observed as salinity increased.

Experimental investigation of drying characteristics of lima beans with passive and active mode greenhouse solar dryers

AbstractIn the study, the thermal performance of the even span and parabolic roof type solar greenhouse dryers is investigated under the active and passive modes under the same operating conditions. Dryers were covered with the 200‐μm UV stabilized polyethylene sheets to enhance the solar insolation effect. The performance of these dryers is evaluated for drying lima beans (Phaseolus lunatus). The moisture content of Lima beans was reduced from 75% (w.b.) to 11% (w.b). For both of active and passive mode conditions, the parabolic dryer could dry in 28 and 32 hr, respectively and that for the even span dryer, it could achieve the same state in 32 and 36 hr, respectively. The open sun drying took as high as 40 hr to dry time for the lima beans. The highest thermal efficiency of the dryers was estimated to be 14.7% for the active mode parabolic dryer and the minimum as 12.03% in the passive mode even span dryers. The nutrition retainment was the highest for parabolic active mode dryer with the payback period as 2.15 years, as against 10 years of expected solid life span and strong suggestion is made for the use of the small scale needful farmers.Practical ApplicationsDrying is an energy consuming processes, and industries require more amount of energy for drying a food grain. In the current scenario, more attention is toward for usage of the Solar based dryers for the abundance of availability of solar energy which makes cost effective. However, the popularly available conventional method of open Sun drying of lima beans resulted in contamination of product from external dirt, degradation due to direct heating, existence of uncontrolled dry rate and additional dry time. To solve the above constraints, in open sun drying and to improve the dried product quality, the author constructed a simple, compact and economically modified greenhouse solar dryer. The quality of dried lima beans under active mode convection parabolic roof was superior. The much needed carbohydrate and protein values, of dried lima beans of 100 g sample for forced convection parabolic roof greenhouse solar dryer had shown the increase of 2 and 10% than open sun dry sample. Among various seeds used to making food stuff, the lima beans are one of the choices for people.

English

The aim of this research was to evaluate the capacity of symbiotic efficiency of native rhizobia from soils of the state of Rio Grande do Sul (RS), Brazil in Phaseolus lunatus L. plants. Soil and nodule samples from predominant legume plants such as Desmodium species were collected in seven locations of the state of RS. For the isolation of the rhizobia from the soil samples, lima bean “olho de cabra preto” variety and “leucena” (Leucena leucocephala) and plants were used as baits. Subsequently, the symbiotic characterization of the isolates was performed by inoculation on lima bean plants in vitro conditions. The selected bacterial isolates were evaluated for biological nitrogen fixation efficiency in a greenhouse experiment, being determined after: shoot dry mass, root dry mass, nodule dry mass, nitrogen (N) accumulated shoot and calculated the N fixation relative efficiency index. Among the 28 rhizobia isolates tested, 11 induced nodule formation in lima bean. The rhizobia Plu03 and Plu14 stimulated a greater increase of plant dry mass, nodule dry mass and nitrogen accumulation in the shoot, reflecting in a higher relative efficiency index. These results suggest that the isolates Plu03 and Plu14 are more efficient in promoting growth of lima bean, which could be recommended for future agronomic efficiency studies. Key words: Rhizobia, lima bean, biological nitrogen fixation.