Faba Bean Roots Research Articles

Symbiotic effectiveness and phylogeny of rhizobia isolated from faba bean (Vicia faba L.) in Sichuan hilly areas, China

A total of 54 rhizobial strains were isolated from faba bean root nodules in 21 counties of Sichuan hilly areas in China, and their symbiotic effectiveness, genetic diversity and phylogeny were assessed. Only six strains increased the shoot dry mass of the host plant significantly (P≤0.05). Based on the cluster analysis of combined 16S rDNA and intergenic spacer region (IGS) PCR-RFLP, the strains were divided into 31 genotypes in 11 groups, indicating a high degree of genetic diversity among the strains. The sequence analysis of three housekeeping genes (atpD, glnII and recA) and 16S rDNA indicated that the strains represented two R. leguminosarum, two Rhizobium spp., R. mesosinicum, Agrobacterium sp. and A. tumefaciens. The strains representing four Rhizobium species were divided into two distinct nodC and nifH genotypes. However, the phylogeny of housekeeping genes and symbiotic genes was not congruent, implying that the strains had been shaped by vertical evolution of the housekeeping genes and lateral evolution of the symbiotic genes.

Intercropping of Faba Bean with Wheat Under Low Water Availability Promotes Faba Bean Nodulation and Root Growth in Deeper Soil Layers

The symbiotically fixed N is advantageous to legumes growing under N-limiting conditions, and is also potentially beneficial for subsequent or associated non-legume crops1,2. However, under stressful conditions such as water limitation and low nutrient availability, legumes may lose the distinct advantage of an unlimited source of symbiotic N2 3,4,5. Belowground niche complementarity in legume-cereal intercrops may improve resource use efficiency and adaptability to environmental constraints, but effects of water limitation on legume rooting and nodulation patterns is poorly understood. To advance our knowledge of mechanisms involved in water stress response, faba bean (Vicia faba L., FB) and wheat (Triticum aestivum L.) were grown as mono- and intercrops in soil-filled plexiglass rhizoboxes under water sufficiency (80% of field capacity; FC) and water stress (30% of FC). Water stress decreased shoot biomass in both monocropped and intercropped FB, as well as root length in monocropped FB. Intercropping increased both shoot dry weight and height of FB irrespective of water treatment, while increased root biomass and length in intercropped FB was observed only under water stress. No significant effects of crop or water treatment were found on wheat growth parameters. Intercropping increased overall nodulation (nodule number and nodule dry weight; NDW) regardless of water availability. However spatial patterns of nodulation differed between water treatments: top-15-cm NDW and number increased (27 and 33%, respectively) in sufficiently-watered intercropped FB, while NDW in the same soil layer significantly decreased (45%) in water-stressed intercropped FB. In contrast, below-15-cm NDW and number significantly increased in intercropped FB under both water levels. This enhanced nodulation in the deeper soil layer and the associated increase in root and shoot growth provides evidence for a shift in niche occupancy that improves FB performance when exposed to water limitation in intercropping.

Diversity of Rhizobia Nodulating Faba Bean (Vicia faba) Growing in Egypt

The aim of this work was to characterize and to describe the diversity and phylogeny of rhizobial bacteria associated to nodules of faba bean in four different geographical regions of north Egypt. Eight rhizobial isolates from healthy faba bean roots were isolated. They were identified as Rhizobium leguminosarum morphologically. They showed sensitivity to Kanamycin, Neomycin and Sulphemethooxazole antibiotics. Mannitol was the best source of carbon source for their growth. However, two isolates Rl. 2 and Rl. 10 indicated better tolerance to high NaCl concentrations than the other isolates and their plasmid profiles contained additional large plasmid with molecular weight about 23 kb. A relationship between salt tolerance and extra plasmid was suggested. Analysis of similarity among rhizobial isolates by using the RAPD-PCR technique showed a high level of genetic polymorphism, grouping the rhizobial isolates into two different clusters. These clusters reflexed the similarity among genotype of isolates independent of their geographic locations. 16S rDNA sequences of three representing isolates were determined and were aligned and compared with the 16S rDNA sequences of other members of the family Rhizobiaceae available in the Gene Bank database. The obtained dendogram indicated that the isolates belonging to Rhizobium leguminosarum biovar viciaen.

Tunisian Rhizoctonia solani AG3 strains affect potato shoot macronutrients content, infect faba bean plants and show in vitro resistance to azoxystrobin

Rhizoctonia solani reduces quality and yield of potato crops in the south of Tunisia and has become an impediment for potatoes export. The lack of studies on the pathogen prompted us to characterize the growth capacity at different temperatures, the aggressiveness, the host specificity and the sensitivity to the fungicides fludioxonil, pencycuron and azoxystrobin of local R. solani strains. Morphological characterization and sequencing of the rDNA ITS gene of the fungal strains showed that they belong to R. solani anastomosis group 3 (AG3). All strains showed a maximum growth at 25 °C with a preference to cold (15–20 °C) in comparison to high temperatures (30–36 °C). All R. solani strains decreased potato shoot dry weight in infected versus control plants. The nitrogen and potassium levels were higher in the shoot of infected potato plants in comparison to the control; however the opposite behaviour was noticed for phosphorus concentration, indicating an imbalance in the nutritional statue of infected potato plants. The effect of R. solani on potato macronutrients uptake is discussed. All R. solani strains were able to infect faba bean roots with the strain RS5.2 reduced significantly plant growth and nodulation. Therefore, faba bean may provide a suitable alternative host for R. solani AG3. The local R. solani strains were highly sensitive to fludioxonil (EC50: 0.007 μg a.i. ml−1) and pencycuron (EC50: 0.006 μg a.i. ml−1); but resistant to azoxystrobin with an EC50 exceeding 19 μg a.i. ml−1. This highlights the risk of resistance to quinone outside inhibitor fungicides (QoI) in R. solani populations, although up to now no decrease in field performance was noticed. It is recommended to delay build up of QoI resistance by an integrated approach, combining optimised fungicide use with the choice of R. solani resistant cultivars and the application of farming practices.

Associations of biophysical factors with faba bean root rot (Fusarium solani) epidemics in the northeastern highlands of Ethiopia

Two field surveys were conducted during the 2010 and 2011 cropping seasons to determine the distribution and importance of faba bean root rot, Fusarium solani (Mart) Apple and Sacc. in the northeastern highlands of Ethiopia. The associations of the root rot incidence and severity with independent variables was analyzed using a logistic regression model. The associations of disease incidence and severity with biophysical factors were evaluated. The disease incidence and severity varied among soil types, crop management practices and cropping seasons. Disease incidence and percentage severity index were higher in 2010 (44.6%) than 2011 (44.4%) due to the high rainfall in 2010. Cropping season, soil type, land preparation and weed management practices were significantly associated with faba bean root rot incidence and percentage severity index in a multiple-variable model. A root rot incidence of ≤50% and severity of ≤40% showed high probability of association with season, furrow sowing and weed management practice, whereas vertisols, flat sowing, high soil moisture and high weed density had significant contributions to root rot epidemics. In contrast, elevation, cropping system and crop density were not associated with the root rot incidence and percentage severity index. Our results showed that root rot is a major biotic constraint in the study area and suggested that proper soil drainage and weed management practices could contribute to reduce the impact of the disease until resistant faba bean genotypes are developed and distributed to small-scale faba bean growers in northeastern Ethiopia and other similar areas of the country.

The Potential of Cell-free Cultures of Rhizobium leguminosarum, Azotobacter chroococcum and Compost Tea as Biocontrol Agents for Faba Bean Broomrape (Orobanche crenata Forsk.)

In the present study, cell-free cultures of four isolates of Rhizobium leguminosarum, an isolate of Azotobacter chroococcum and compost tea were investigated for their biocontrol potential against the root parasitic weed Orobanche crenata. Individual cell-free cultures of Azotobacter chroococcum or Rhizobium sp., dual and mixture of cell-free cultures of Rhizobium spp. or compost tea were applied to infested pots in greenhouse conditions. The treatments showed variable effects on many developmental parameters of both faba bean and broomrape. Significant decrease in the number of broomrape attachments, dry weight of the attached tubercles on faba bean roots and the reduction in percentage of broomrape seed germination were recorded. Compost tea, individual and mixture of R. leguminosarum isolates were more reducing on broomrape germination and growth than A. chroococcum alone did; being the former treatment is the best. The reduction in broomrape incidence by compost tea was due to certain phenotypic mechanisms, which acted alone or in combination. These mechanisms included negative effect of natural stimulant broomrape on seed germination, prevention of radical penetration inside the host roots, parasite yield reduction, and thus increasing the growth and vitality of faba bean. In vitro experiment indicated that seed germination percentage of broomrape was also negatively affected by the combination of root-exudates and compost tea. Radical apexes of the germinated seeds were distorted. These distortions may prevent the radicals to follow up the infestation. In conclusion, the study presents the potential of R. leguminosarum isolates and compost tea in biocontrol of broomrape. More investigations should be carried out with viable bacterial cells on the parasite plant before use in sustainable agricultural systems.

Evaluation of Gene Expression for Orobanche Tolerance in Faba bean (Vicia faba L.)

Two faba bean cultivars were studied for Orobanche (Orobanche crenata, forsk) tolerance. A greenhouse experiment was conducted using two Egyptian faba bean (V. faba L.) cultivars infected by Orobanche crenata in a pot trial. Results of the control plants (without Orobanche infection) and infected plants (with or without Orobanche attachment) proved that Giza 3 was the susceptible cultivar and G.843 was tolerant which had the lowest Orobanche tubercles per plant. Spectrophotometer was used to assess total protein, peroxidase and polyphenoloxidase activity extracted from faba bean roots and shoots. SDS-PAGE of roots and shoots extracts and isozymes-electrophoreses were used to assess the genetic expression of the two faba bean cultivars according to their banding patterns.

Essential Oils and Trichoderma Harzianum as an Integrated Control Measure Against Faba Bean Root Rot Pathogens

Essential Oils andTrichoderma Harzianumas an Integrated Control Measure Against Faba Bean Root Rot PathogensCarnation, caraway, thyme, peppermint and geranium essential oils have been found to have inhibitory effects against the mycelial growth ofFusarium solani,Rhizoctonia solani,Sclerotium rolfsiiandMacrophomina phaseolinaunderin vitroconditions. Complete inhibition of fungal growth was observed with the use of 4% carnation and geranium oils. Mycelial growth of the tested fungi showed more sensitivity to high concentrations of thyme than to caraway and peppermint oils. Moreover, essential oils used to coat seeds resulted in a significant reduction of root rot incidence of bean, at both pre- and post-emergence stages under greenhouse conditions. Under field conditions seeds coated with essential oils at a concentration of 4% sown in soil treated with the bio-agentTrihoderma harzianum, gave pronounced protection to emerged bean seeds against the invasion of root rot pathogenic fungi. Compared to the control, the above treatment resulted in a reduction of disease incidence at the pre-emergence stage. This reduction was calculated to be between 47.3 and 55.4% compared with a 16.1% reduction with the use of the Rizolex-T treatment. At the post-emergence stage, all applied treatments were able to reduce the percentage of root-rot incidence. Reduction ranged between 41.4 and 47.1% over the untreated control. Reduction in disease incidence was reflected in a yield increase of 15.1-28.8% and 40.1-50%, in seeds coated with one of the different essential oils, or combined withT. harzianumsoil treatments, in the respective order. Seeds coated with the fungicide Rhizolex-T caused a yield increase estimated as 11.3% over the check treatment. These results show that application of essential oils in integration with the bio-agentT. harzianummay be considered as an applicable, safe and cost-effective method for controlling such soilborne diseases.

Effect of nitrate concentration on proton release by faba-bean roots

In the effort to understand the mechanisms of enhanced soil acidification by legume plants,the effect of nitrate dose on proton release by the roots of faba-bean under medium pH conditions was analyzed in solution culture experiment and by automatic potentiometric titration at a constant pH.The results show that the roots of faba-bean release the largest amount of protons when no external nitrate source is available,inducing a drastic decline (1.93 units) in medium pH.The cumulative amount of released proton after ten incubations reaches 37.5 mmol per gram dry-root.With increasing nitrate concentration,the amount of released protons and change in medium pH decrease.When nitrate concentration increases to 1.0 mmol·L-1,only a small amount of proton is released at the early stage of the culture experiment (in fact,some amount of OH-is released at the later stage of the experiment).When there is no external nitrate or it is available at low levels,legume plants derive N from biological nitrogen fixation,leading to higher cation than anion uptake.Under this condition,plant roots release protons to ensure that the charges are well in balance.Results also indicate that protons in the culture solutions come mainly from direct releases by faba-bean roots.The effect of organic acid on the amounts of proton in the medium is generally negligible.Addition of nitrate can reduce H+ release by faba-bean roots.

Faba bean root growth in a Vertisol: Tillage effects

Studies on the growth of faba bean ( Vicia faba L.) root systems in Vertisols under Mediterranean climates are practically non-existent. A three-year field study (2003–2004, 2005–2006 and 2006–2007) was conducted on a typical Vertisol (in southern Spain) to determine, using a minirhizotron system, the effects of tillage on root growth in faba bean grown in continuous rotation with wheat ( Triticum aestivum L.) as part of the long-term “Malagón” experiment that started in 1986. Tillage treatments were no-tillage (NT) and conventional tillage (CT). The parameters measured were root length (RL), root diameter (RD), root biomass (RB), seed yield and aboveground biomass. Root growth measures with minirhizotron were carried out at six soil depths for five growth stages throughout the faba bean growing season. For the calculation of RB, soil cores were collected during flowering from the same six soil depths. NT was more favorable for the development of the faba bean root system when compared with CT. This can be attributed to improved physical properties of the soil under NT, which improves the water conditions of the soil.

Long-term activity of bio-priming seed treatment for biological control of faba bean root rot pathogens

The long-term activity of some antagonistic fungal and bacterial agents against the incidence of faba bean root rot incidence was evaluated when applied as a bio-priming seed treatment. The inhibitory effect of antagonistic fungi and bacteria against the linear growth of root rot pathogenic fungi was evaluated in vitro. The tested inhibitor factor in this study was the antagonistic agents applied as either growth culture discs or bio-primed faba bean seeds. The inhibitor effect of Trichoderma viride, T. harzianum, Bacillus subtilis and Pseudomonas fluorescens was significantly higher than T. hamatum and B. cereus, respectively. Similar results were also obtained when the antagonistic agents were applied as bio-primed seeds. Under greenhouse conditions, all the tested fresh and 2 months-stored, bio-primed faba bean seeds showed a highly significant effect causing complete reduction of root rot incidence at both pre — and post-emergence stages of plant growth compared with the control treatment. Stored seeds at 4 and 6 months showed a less protective effect against the incidence of disease. After 3 months of storage under field conditions, the antagonistic agents could protect seeds against infection by root rot pathogens at both pre- and post-emergence stages. However, after 6 months of storage, a lower protective effect was observed. No significance was observed between seeds primed only with adhesive agents and the untreated control. Promising applicable techniques could be suggested in light of the results obtained in the present study. The use of bio-primed seeds might be considered as a safe, cheap and easily applied biocontrol method against these soilborne plant pathogens.

Aphanomyces root rot on faba bean in northern NSW

Aphanomyces euteiches was found to be the causal agent of faba bean root rot in northern NSW, both in experimental and commercial fields. Resistance to Aphanomyces root rot appears to be common in the faba bean germplasm pool, but the susceptibility of some varieties justifies further research on the pathogen. This is the first report of A. euteiches as a faba bean pathogen in Australia.

Efficacy Of Solarization And Seaweeds Amendment In The Control Of Faba Bean Fusarial Root Rot

The role of soil solarization with or without seaweeds (Caulerpa prolifera and Ulva lactuca) amendment on the faba bean root rot caused by Fusarium solani f. sp. fabae was evaluated under field conditions. Soil temperature in solarized plots reached a maximum of 55, 53ºC at the two depths 5 and 10 cm respectively. These temperatures were 10 to 13ºC higher than in corresponding unsolarized plots. Solarization alone or in combination with Caulerpa and Ulva amendment reduces disease severity from 35 % (control) to 85 %, 88 % and 80 % respectively. While combination of Caulerpa with solarization exerts a sort of synergistic effect, by increasing number of healthy plants from 80 % in unsolarized amended soil to 88 % in solarized amended soil, combination of Ulva with solarization showed antagonistic effect by decreasing number of healthy plants from 85% in solarized soil to 80 % in Ulva amended soil. New Egyptian Journal of Microbiology Vol. 17 (2) 2007: pp. 214-223

Biological Control of Faba Bean Pathogenic Fungi by Three Cyanobacterial Filtrates

The aim of the present study is to evaluate the biological control aptitude of the cyanobacteria, Anabaena subcylindrica, Nostoc muscorum and Oscillatoria angusta filtrates on the growth of the isolated pathogenic fungi from the different organs of Faba bean. Three caynobacterial (Anabaena subcylindrica, Nostoc muscorum and Oscillatoria angusta) filtrates were prepared in different concentrations and their effects on the isolated pathogenic fungi from leaves, stems and roots of Faba bean were studied. The study revealed high efficiency of the three algal filtrates on the control of the isolated pathogenic fungi from the three organs of Faba bean plants. The reduction in fungal mat growth diameter was greater than in that of the fungal dry weight showing inhibited fungal spread by greater rate. The reduction in the fungal dry weight was mostly linear and significantly correlated with the algal filtrate concentrations. The Efficient Algal Filtrate Concentration (EAFC) ranged between 104 and 461% for the three algal filtrates on the studied fungi dry weight. Complete control of the isolated fungi could be achieved by of a mixture of two algal filtrates in their EAFC and that of Nostoc muscorum + Oscillatoria angusta filtrates with an EAFC 368 and 194% were the best and economic mixture.

Differences in lipid and in fatty acid composition of taproots and lateral roots of faba bean plants (Vicia faba L.) grown in saline media

The content and composition of lipids and fatty acids of taproots and lateral roots of Vicia faba were investigated with plants grown under saline (80 mM NaCl) and non-saline conditions. Lipids of both types of faba bean roots are constituted of ∼80% phospholipids, of ∼15% glycolipids and of some 5% of wax-esters. Phosphatidylethanolamine (PE) and phosphatidylcholine are the main constituents of both root types. Di-phosphatyidylglycerol and phosphatidylinositol are present in medium concentrations, whereas phosphatidylglycerol and phosphatidylserine are present only in trace amounts. The content of sulpholipids was much lower in salt-treated roots as compared with that of the controls. The content of cardiolipins and PE was higher in lateral roots than in the taproots. Roots of salt-treated plants had some 18% lower ether-soluble lipid content in the lateral roots, and approximately 28% lower than the taproots. Less than 25% of the fatty acids of the extracted phospholipids were saturated, with palmitic acid as the main constituent (13 – 18%). Linoleic acid comprised 65 – 70% of the unsaturated acids. Differences in the composition of some fatty acids were found between taproots and lateral roots of salt-treated plants. The observed differences in composition between root types suggests that the reported physiological differences between such roots could be based, at least in part, on structural or compositional differences in their lipids.

Simulating crop–parasitic weed interactions using APSIM: Model evaluation and application

The parasitic weed Orobanche crenata inflicts major damage on faba bean, lentil, pea and other crops in Mediterranean environments. The development of methods to control O. crenata is to a large extent hampered by the complexity of host–parasite systems. Using a model of host–parasite interactions can help to explain and understand this intricacy. This paper reports on the evaluation and application of a model simulating host–parasite competition as affected by environment and management that was implemented in the framework of the Agricultural Production Systems Simulator (APSIM). Model-predicted faba bean and O. crenata growth and development were evaluated against independent data. The APSIM-Fababean and -Parasite modules displayed a good capability to reproduce effects of pedoclimatic conditions, faba bean sowing date and O. crenata infestation on host–parasite competition. The r 2 values throughout exceeded 0.84 (RMSD: 5.36 days) for phenological, 0.85 (RMSD: 223.00 g m −2) for host growth and 0.78 (RMSD: 99.82 g m −2) for parasite growth parameters. Inaccuracies of simulated faba bean root growth that caused some bias of predicted parasite number and host yield loss may be dealt with by more flexibly simulating vertical root distribution. The model was applied in simulation experiments to determine optimum sowing windows for infected and non-infected faba bean in Mediterranean environments. Simulation results proved realistic and testified to the capability of APSIM to contribute to the development of tactical approaches in parasitic weed control.

Phenolic acid changes during Orobanche parasitism on faba bean and some other hosts

The present work is intended to provide further information on broomrape parasitism based on phenolic acid changes in either the host plant(s) or in each of the host and the parasite in the host-parasite system. Detection of phenolic acids was carried out using high performance liquid chromatography (HPLC) in the host and broomrape tissues. This was carried out first in shoots and roots of faba bean before (33-day-old) and after (65-, 74-, 80-day-old) broomrape infestation. Shoots and roots of faba bean and other prospective hosts (tomato and eggplant), during parasitism, at full juvenility of broomrape just before blooming, were also scanned. Chlorogenic acid occurred predominantly as phenolic compounds in shoots and roots of the host plants. The occurrence of chlorogenic acid was unique to the roots of the faba bean plant at different stages of development of the parasite, as well as in the roots of other infected hosts. In shoots of the infected hosts, inconsistent variations were observed in the ratios of caffeic, ferulic, as well as ortho-, para- and metacoumaric acids. Detection of phenolic acids in stems of broomrape, parasitizing faba bean, indicated the occurrence of chlorogenic acid at different stages of growth of the parasite. In addition to chlorogenic acid, the results also revealed the existence of M-coumaric acid at the emergence stage, P-coumaric and ferulic acids at early blooming and caffeic acid at the late blooming stage. Qualitative changes were also observed in broomrape tissue according to the type of host (faba bean, chamomile, eggplant, and cabbage). On the other hand, chlorogenic acid was the only phenolic compound detected in the corm-like tubercle tissue of broomrape with different hosts. The possible interference of phenolic acids in tissues of both the hosts and broomrape was discussed. KEY WORDS: Broomrape parasitism, Phenolic acids, HPLC, faba bean. Egyptian Journal of Biology Vol.4 2002: 37-44

Effects of mycorrhizae and chitin-hydrolysing microbes on Vicia faba

The effect of Streptomyces albovinaceus (S-22) and Bacillus sp. (B1) on the growth response, nodulation, nutrition and nitrogenase activities of faba bean (Vicia faba) varieties infected with Glomus mosseae under pot conditions in sterile soil amended with chitin was studied. The growth, nodulation, nutrients content and nitrogenase activity of mycorrhiza-treated plants of Giza-667 were significantly increased compared to untreated ones. Such increases were related to the increase in mycorrhizal root infection. Amendment of soil with chitin alone reduced the growth, nodulation, total nitrogen contents and nitrogenase activities of mycorrhiza-treated faba bean plants (Giza-667) compared to untreated plants. Inoculation of plants with S. albovinaceus or Bacillus sp. significantly increased the level of mycorrhizal roots infection, but addition of chitin to the soil in combination with Bacillus sp. reduced the mycorrhizal infection of faba bean roots. Highest phosphorus contents of faba bean Giza-667 were recorded after G. mosseae inoculation in the presence of all treatments. Similar results were observed for the other varieties. The microbial populations were significantly increased in rhizospheres amended with chitin. Such increases were not in response to the mycorrhizal inoculation. Generally, the microflora of faba bean rhizospheres was increased after treatment with G. mosseae in the absence of chitin amendment alone compared with non-mycorrhizal rhizospheres.

Partial purification and characterization of NADH-glutamate synthase from faba bean ( Vicia faba) root nodules

The NADH-dependent glutamate synthase (EC 1.4.1.14) from the plant fraction of N 2-fixing faba bean ( Vicia faba) nodules has been purified 74-fold to a specific activity of about 3 μmol min −1 mg protein −1 with a final yield of 32%. The NADH-GOGAT activity was associated with a single form of the enzyme that behaved as a monomeric protein with a subunit molecular weight of 195 kDa and a native molecular weight from 222 to 236 kDa estimated by gel filtration or PAGE, respectively. The NADH-GOGAT band on SDS-PAGE was cut out and used to produce antibodies. Western blots of SDS-PAGE of crude nodule proteins revealed a 195 kDa polypeptide in root extracts but not in those of leaves or bacteroids. The antiserum also cross-reacted with a polypeptide of camparable molecular weight (195 kDa) from both amide and ureide transporting species legume nodules, indicating that some antigenic epitopes have been conserved between nodule NADH-GOGAT of different species.

Simulation of faba bean ( Vicia faba L.) root system development under Mediterranean conditions

Root growth of faba bean genotype ILB 1814 grown under both limited and sufficient moisture supply was studied in 1993–1994 and 1994–1995 at ICARDA's Tel Hadya research station. Crops were sown on two dates in both growing seasons. Root-length density (RLD) and root dry weight were measured at four depths in three locations relative to the crop row. In general, RLD decreased considerably with depth, and by the start of pod-filling, around 60% of the roots were found in the top 15 cm of soil. In the upper 30 cm soil profile, the RLDs of drought-stressed faba beans were significantly lower than those measured beneath well-watered crops. In the deeper soil layers, the RLDs were similar in both moisture supply treatments. An existing root model was employed for the simulation of faba bean root growth. The model estimates the depth of rooting and RLD in each soil layer based on dry matter allocation to the root system, soil layer water contents, genotype-specific rooting characteristics, and soil physical properties. A faba bean growth model provided daily allocation of dry matter to roots as well as soil layer water contents. Overall, with a few modifications, the root model was capable of predicting the RLD of faba bean grown both under limited and sufficient water supply realistically. Limitations of the model and some aspects that need further improvement are discussed.