Vicia Research Articles

A hemiterpene glucoside as a probing deterrent of the bean aphid, Megoura crassicauda, from a non-host vetch, Vicia hirsuta

The bean aphid, Megoura crassicauda Mordvilko, feeds selectively on plants belonging to the genus Vicia (Fabaceae). However, it never infests the tiny vetch, V. hirsuta (L.) Gray. The aphid appeared to discriminate between host and non-host plants by tasting specific chemicals during penetration of its stylet into the plant tissues. The aphid, after being stimulated by specific probing stimulants, deposited characteristic proteinous stylet sheaths through a parafilm membrane, which has one side in contact with an extract solution of Vicia angustifolia. However, an addition of a V. hirsuta extract to the medium strongly inhibited the salivary sheath formation. A specific probing deterrent was isolated from a V. hirsuta extract by monitoring the inhibitory effect, and identified as ( E)-2-methyl-2-butene-1,4-diol 4- O-β- d-glucopyranoside. A mixture of the glycoside and the stimulatory V. angustifolia fraction in the same equivalency found in plants significantly decreased the probing activity in M. crassicauda. Since the stylet insertion process is a crucial step for the aphid’s settlement on a plant, the glycoside seems to act as an effective chemical barrier for V. hirsuta.

Phylogenetic analyses within three sections of the genus Vicia.

The averaged genomic similarities based on multilocus randomly amplified polymorphic DNA (RAPD) were calculated for eight species representing three sections of the genus Vicia: faba, bithynica and narbonensis. The frequency of appearance of the sequences corresponding to 25 decamers selected at random from genomes of different Fabace species was checked, and a high correlation with the frequency observed for Vicia allowed us to assume their similar weight in typing Vicia species. The RAPD-based similarity coefficients compared with those related to whole genome hybridization with barley rDNA and those based on restriction fragment length polymorphism (RFLP) revealed similar interspecies relationships. The averaged RAPD-based similarity coefficient (Pearson’s) was 0.68 for all the species, and was sectionspecific: 0.43 (bithynica), 0.50 (faba) and 0.73 (narbonensis). The averaged similarity coefficient for V. serratifolia (0.63) placed it apart from the rest (0.75) of its section. The results correspond to the interspecies relationships built upon non-genetic data. The averaged similarity coefficient for particular RAPD was related to the presence and type of tandemly repeated motif in a primer: 0.7–0.8 for heterodimers (GC, AG, CA, GT, CT), 0.5–0.6 for homodimers (CC, GG) and 0.6 for no repeat, indicating the sensitivity of diversity range to the type of target sequences.

Isozyme Variation and Phylogenetic Relationships in Vicia subgenus Cracca (Fabaceae)

The phylogenetic relationships among 27 vetch species belonging to the subgenus Cracca of the genus Vicia were studied in comparison with three species of Lathyrus section Lathyrus on the basis of isozyme variation. Isozymes encoded by 15 putative loci of ten enzymes were resolved by polyacrylamide gel electrophoresis and isozyme variation was analysed by using parsimony and neighbour-joining methods. The analyses revealed 63 parsimony-informative and 36 species-specific orthozymes. Of the latter, 23 are monomophic and are suitable for identification of V. benghalensis, V. palaestina, V. dumetorum, V. pisiformis, V. sylvatica, V. onobrychioides, V. cappadocica, V. cretica, V. articulata, V. tetrasperma, V. ervilia, V. hirsuta and V. loiseleurii. Polymorphism with heterozygous and homozygous isozyme genotypes was found for V. cracca, V. tenuifolia, V. ochroleuca, V. villosa, V. sylvatica, V. cassubica, V. sparsiflora, V. megalotropis, V. altissima, V. onobrychioides, V. cassia, V. cretica and L. heterophyllus, reflecting outcrossing in these species. By contrast, V. benghalensis, V. palaestina, V. disperma, V. dumetorum, V. pisiformis, V. orobus, V. pauciflora, V. tetrasperma and V. loiseleurii had only homozygous isozyme genotypes at polymorphic loci. Isozyme-based phylogenetic trees are presented. Sections Cracca, Ervum, Pedunculatae and Lenticula of traditional taxonomy are monophyletic groups, whereas sections Oroboideae (= Vicilla) and Panduratae appear polyphyletic and section Cassubicae is split into two species-couples linked at a low level of support. Treatment of ervoid species in a separate subgenus Ervum is not supported because of its polyphyly.

VARIABILITY OF PRODUCTIVITY ELEMENTS AT VICIA FABA L. GENOTYPES AFTER GAMMA-RAY TREATMENT ON M3 GENERATION

The phenotypic effect and the mutations frequency very much depend on the genetic background in which they produce and become manifest, as well as on the gene nature or the genetic material upon which the inductive agent drives. There were taken under study two Vicia faba L. genotypes. There were applied mutagen treatments with gamma rays in seven doses, both at dry seeds and wet seeds. The observations were carried out on three generations. The following features were tracked down: the plant height, the number of fertile pods/plant, the number of sterile pods/plant and the seed weight/plant. In the present paper the data obtained in the M3 generation are displayed. The study has revealed some negative effects, such as the increase of the number of sterile pods, but at the same time some favorable changes. Hence, statistically insured differences were obtained for the plant height, the number of seeds/plant or their weight. The positive values were recorded at the level DL 50 %. One can notice the differentiated reaction of the two genotypes at the dose of the mutagen agent and the different reaction to the type of the treatment applied (at dry or wet seeds).

Retrotransposon populations of Vicia species with varying genome size

The (non-LTR) LINE and Ty3-gypsy-type LTR retrotransposon populations of three Vicia species that differ in genome size (Vicia faba, Vicia melanops and Vicia sativa) have been characterised. In each species the LINE retrotransposons comprise a complex, very heterogeneous set of sequences, while the Ty3-gypsy elements are much more homogeneous. Copy numbers of all three retrotransposon groups (Ty1-copia, Ty3-gypsy and LINE) in these species have been estimated by random genomic sequencing and Southern hybridisation analysis. The Ty3-gypsy elements are extremely numerous in all species, accounting for 18-35% of their genomes. The Ty1-copia group elements are somewhat less abundant and LINE elements are present in still lower amounts. Collectively, 20-45% of the genomes of these three Vicia species are comprised of retrotransposons. These data show that the three retrotransposon groups have proliferated to different extents in members of the Vicia genus and high proliferation has been associated with homogenisation of the retrotransposon population.

Specific differentiation in Vicia genus by means of capillary electrophoresis

Capillary electrophoresis has been applied to the discrimination of 13 Vicia species, belonging to four sections of Vicia genus. The studied species necessitate of plant growing tests or DNA molecular markers to be distinguished being their seeds morphologically very similar. Alcoholic/saline extracts from dry cotyledons were separated in uncoated fused-silica capillary with iminodiacetic acid isolectric buffer containing hydroxypropylmethylcellulose and acetonitrile. The low intra-specific variation observed for 11 species, suggests that this approach is suitable to carry out species discrimination. Species-specific peaks were identified for V. articulata, V. atropurpurea, V. bithynica, V. benghalensis, V. disperma, V. ervilia, V. monantha, V. sativa and V. villosa. Conversely, V. lutea, V. melanops and V. peregrina, showing very similar electrophoregrams, require other methodological approaches to be discriminated. The discussed CE method appears to have a potential to be regarded as an alternative tool to identify some Vicia species being far less expensive and time consuming than plant growing tests and DNA molecular markers.

Vetch (Vicia spp) expansion and use in Australia

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Analysis by detached leaf assay of components of partial resistance of faba bean (Vicia faba L.) to chocolate spot caused by Botrytis fabae Sard

Five faba bean (Vicia faba L.) genotypes with different levels of field susceptibility to chocolate spot caused by Botrytis fabae, were analysed for the components of partial resistance in a laboratory assay on living detached leaves. The incubation period (IP), the number of spots (NP), the lesion diameter (LD), the latency period (LP) and the number of spores/leaflet (NS), were determined and statistically analysed. Parameters LD, LP and NS were involved in characterising partial resistance, but IP did not appear to play a role. NS did not become a significant factor until 20 h after inoculation. Genotype FRY167 was most resistant with the lowest LD and NS values and the longest LP. In contrast, FRY30 had the highest level of susceptibility, with the highest LD and NS and the shortest LP. However, the resistant control BPL710 showed a slight deviation in that it expressed a long LP which was not significantly different from the values of the susceptible control Aguadulce. The absence of a correlation between LP and NS in BPL710 opens a discussion on the genetic control of its resistance.

Agricultural potential of Mediterranean grain and forage legumes: 2) Anti-nutritional factor concentrations in the genus Vicia

As part of an investigation into the agricultural potential of under-exploited Mediterranean Viceae, anti-nutritional factor concentrations were measured in the seed of 7 species. These included: V. sativa(subsp. amphicarpa(L.) Batt., subsp. macrocarpa(Moris) Arcang, subsp. nigra(L.) Ehrh., subsp. sativa), V. ervilia L., V. faba L. (var. faba, var. minor Peterm.), V. narbonensis L. (var. aegyptiaca Kornhuber ex Asch. et Schweinf., var. affinis Kornhuber ex Asch. et Schweinf., var. jordanica H. Schaef., var. narbonensis, var. salmonea(Mout.) H. Schaef.), and relatives, including V. johannis Tamamsch., (var. johannis, var. procumbens H. Schaef.), V. hyaeniscyamus Mout., and V. serratifolia Jacq. Both quantitative and qualitative differences in seed chemistry were observed. Condensed tannins, phenolics and proteinase inhibitors were found in varying concentrations in all taxa. The highest concentrations of phenolic secondary metabolites (0.8–1.4% leucocyanidin equivalents, 9.5–16.4 mg/g phenolics) were found in V. faba, the V. narbonensis relatives and V. sativa subsp. macrocarpa. These taxa also tended to contain low levels of proteinase inhibitors (0.25-0.55 mg trypsin/mg protein), whereas the opposite was the case for V. ervilia(2.1 mg t/mg p). V. narbonensis was intermediate both in terms of tannin and proteinase inhibitor levels. In contrast, the non-protein amino acids tended to be more specific in their distribution. Concentrations of canavanine varied from 0.04-0.11% in the seed of V. ervilia, and may constrain the end-use of the grain, given that pigs are sensitive to concentrations as low as 0.08% in their diet. In V. sativa variation of γ-glutamyl-β-cyanoalanine within and between subspecies (0.41–1.36%) is not sufficient to make the grain palatable to monogastrics, since > 0.075% inclusion in the diet causes mortality in chicks. In V. narbonensis, there was no significant variation between most varieties for γ-glutamyl-S-ethenyl cysteine (GEC), a non-protein amino acid peptide which reduces grain palatability. However, lower concentrations were found in V. n. var. jordanica and its near relatives, V. johannis, V. hyaeniscyamus and V. serratifolia(1.3-1.6%, compared with 1.9+/−0.02% in all remaining V. narbonesis sub-species). Anti-nutritional factor concentrations were used to visualize taxonomic relationships using hierarchical cluster analysis. The V. narbonensis varieties were closely aligned with their near relatives, V. johannis, V. hyaeniscyamus and V. serratifolia. In contrast V. faba was positioned closer to the V. sativa subspecies than either to V. narbonesis or its near relatives. V. ervilia was the most distantly related species. Across all taxa proteinase inhibitors and condensed tannins or total phenols were negatively correlated (r=− 0.72, P < 0.009). This may be a mechanism which minimizes wasteful resource allocation to chemical defense, because the 2 anti-nutritional factors are functionally substitutable, since they both reduce the availability of protein in plant material. Thus taxa investing in high concentrations of proteinase inhibitors do not duplicate chemical defense mechanisms by simultaneously producing large amounts of tannins and phenolics.

Acylated flavonol glycosides as probing stimulants of a bean aphid, Megoura crassicauda, from Vicia angustifolia

A bean aphid, Megoura crassicauda, which feeds selectively on the plant genus Vicia (Fabaceae), was found to be stimulated to probe an extract solution of the host plant, narrowleaf vetch, Vicia angustifolia L., depositing characteristic stylet sheaths on a parafilm membrane. Two acylated flavonol glycosides were isolated as the specific probing stimulants from the extracts and characterized as quercetin 3- O-α- l-arabinopyranosyl-(1→6)-[2″- O-( E)- p-coumaroyl]-β- d-glucopyranoside and quercetin 3- O-α- l-arabinopyranosyl-(1→6)-[2″- O-( E)- p-coumaroyl]-β- d-galactopyranoside. A mixture of these compounds in the same equivalency strongly induced the probing response from M. crassicauda, suggesting their kairomonal roles during host recognition.

New faba bean genotypes resistant to chocolate spot caused by "Botrytis fabae"

The response of sixty-seven genotypes of faba bean (Vicia faba) to the virulent isolate IBf24 of Botrytis fabae was studied under field conditions. Five of these genotypes (LPF39, LPF113, LPF44, LPF237 and LPF05) were moderately resistant to chocolate spot according to their MDI (mass disease index). Ten lines (LPF38, LPF41, LPF64, LPF95, LPF106, LPF132, LPF225, LPF228, LPF23, LPF233) were moderately susceptible, and fifteen lines (LPF54, LPF61, LPF66, LPF89, LPF124, LPF129, LPF131, LPF134, LPF138, LPF152, LPF173, LPF174, LPF190, LPF274, BPL710) susceptible as shown by their MDI values but with low AUDPC (area under disease progress curve) values and were believed to have an overall tolerance to the disease. Fourteen of the genotypes tested in the field, as well as the resistant BPL710 and the susceptible Rebaya 40 controls, were further screened under greenhouse conditions in order to confirm the field evaluation. In both the field and the greenhouse trials, the four lines LPF44, LPF237, LPF05 and LPF113 showed the highest level of resistance to the disease. These trials also revealed that genotypes with only overall tolerance may yet constitute interesting sources of resistance. Genotype BPL710, with known resistance to B. fabae races in the Mediterranean region, was found to be susceptible in the field but moderately susceptible in the greenhouse, suggesting the appearance of new races of this pathogen.

Cladistic and phenetic analysis of relationships in Vicia subgenus Vicia (Fabaceae) by morphology and isozymes

Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus of the genus Vicia in comparison with V. dumetorum, V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different ways of coding. Morphological analyses showed the subgenus Vicia monophyletic and revealed subgroups in a general agreement with traditionally recognized sections, except showing V. faba nested within section Narbonensis and ambiguity in the position of V. lathyroides and V. bithynica. Parsimony analysis of orthozymes as presence/absence characters revealed in the subgenus two basic monophyletic clades: 1) V. faba and three species of the section Peregrinae, V. michauxii, V. aintabensis and V. peregrina, in one subclade linked with species of the Narbonensis and Hyperchusa sections together with V. pisiformis of subgenus Cracca in a second subclade; 2) species belonging to sections Vicia, Sepium, Pseudolathyrus and Lathyroides together with V. sylvatica of the subgenus Cracca. Neighbour-joining analysis of orthozymes revealed the same two basic groups, differing only in the relative position of some species in subclusters. Both isozyme analyses showed paraphyly of the subgenera Vicia and Cracca. Parsimony analysis of orthozymes as character states of isozymes yielded a largely unresolved strict consensus cladogram of 209 most parsimonious trees, and reweighting of characters failed to produce a stable tree. Phylogenetic congruence and discordance among morphological and isozyme analyses, coding ways, homoplasy and weighting of characters are discussed.

ヘアリーベッチ葉に含まれる植物生長阻害物質としてのシアナミドの同定

ヘアリーベッチ葉に含まれる植物生長阻害物質としてのシアナミドの同定

Cytotaxonomic investigations on some taxa of the genus Vicia L. from north-eastern Anatolia

In this study, some natural Vicia L. species growing in north-eastern Anatolia were investigated cytotaxonomically. Chromosome numbers and morphologies of the 15 taxa belonging to the Vicia genus were studied by using karyological and numeric taxonomical techniques. Data obtained on chromosome measurements were analysed by using cluster analysis. The chromosome numbers of these taxa have been found as 2n = 10, 12, 14 and 24. The results were considered in conjuction with the literature and karyological analysis results.

Genotype × environment interaction for yield and other plant attributes among undomesticated Mediterranean Vicia species

In order to investigate the agricultural potential of the genus Vicia, and identify traits associated with productivity and responsiveness to environment, 34 undomesticated Mediterranean accessions representing Section Narbonensis (V. johannis, V. narbonensis) and V. sativa were grown in five contrasting environments in northern Syria (growing season rainfall: 76–290 mm).Highly significant genotype × environment interactions were observed for all traits. For most of the components of yield, accession mean performance (productivity)was highly correlated with responsiveness across environments (r = 0.59–0.96), as defined by joint linear regressions. Thus high yielding genotypes tended to be relatively more productive than low yielding genotypes under conditions that favoured high yields. Regression analysis revealed that mean site yields were positively correlated to rainfall (r = 0.85) and its attendant effect on growing season length as measured by cumulative season temperature and phenology (r = 0.59–0.81).In order to examine yield related traits independently of taxonomy, genotypes were grouped into three categories using K-means clustering based on productivity and responsiveness of seed, hay and biological yield. Highly productive/responsive genotypes were tall with high harvest index, large seeds and low fecundity (seeds and pods per plant), whereas unproductive/unresponsive plants tended to be short, highly fecund, with small seeds and low harvest index. Principal components analysis showed that responsiveness, in terms of seed, hay and biological yields, was closely related to phenological plasticity. Thus highly productive/responsive genotypes were able to start flowering earlier than unproductive/unresponsive genotypes in early environments, but significantly later in late, higher rainfall environments. Plant growth habit was also related to yield responsiveness. In environments with little biomass production the proportion of erect plants was high in all three categories. In more favourable, high biomass environments, the proportion of erect plants in unproductive/unresponsive genotypes fell dramatically, but was unchanged among productive/responsive genotypes. We suggest that for unproductive/unresponsive genotypes competition for light is increased under optimal growth conditions. We argue that the optimal combination of fixed and responsive traits in high yielding genotypes results in a `compound interest-type' response to more favourable environments. Highly productive and responsive genotypes can capture resources more effectively than their low yielding counterparts, leading to a positive relationship between performance and responsiveness for most components of yield. Differences in productivity and responsiveness for seed, hay and biological yield reflected Vicia taxonomy, increasing in the following order from low to high: V. johannis, V. sativa, the small seeded V. narbonensis (salmonea, jordanica, affinis) V. n. var. narbonensis, and finally V. n. var.aegyptiaca. V. n. var. aegyptiaca showed the most agricultural potential, since the taxon contained all the properties of productive/responsive genotypes listed above, yielding >1 t/ha under extremely arid conditions (104 mm),and >2.5 t/ha on 290 mm rainfall, confirming its potential for dry environments.

Physical mapping of 18S-5.8S-26S and 5S ribosomal RNA gene families in three important vetches (Vicia species) and their allied taxa constituting three species complexes

The most-important vetch species, Vicia narbonensis (narbon vetch, section Faba), Vicia villosa (hairy vetch, section Cracca) and Vicia sativa (common vetch, section Vicia) and their close relatives (often difficult to circumscribe into distinct taxa) constitute respectively, Narbonensis, Villosa and Sativa species complexes in the genus Vicia. The distribution of the 18S-5.8S-26S (18S-26S) and 5S ribosomal RNA (rRNA) gene families on the chromosomes of 19 (2n=2x=10,12,14) of the 24 species and subspecies belonging to the three species complexes, and Vicia bithynica (2n=12, section Faba) and Vicia hybrida (2n=12, section Hypechusa) was studied by fluorescence in situ hybridization (FISH) with pTa 71 (18S-26S rDNA) and pTa 794 (5S rDNA) DNA clones. Computer – aided chromosome analysis was performed on the basis of chromosome length, the arm-length ratio and the position of the hybridization signals. The positions of the four (2+2) signals of the two rRNA gene families were similar between each of the three, as well as two subspecies of V. narbonensis and Vicia johannis, respectively. Two major 18S-26S rDNA loci were found in the nucleolus organiser regions (NORs) of each of the species except V. hybrida, where it was present in two out of four SAT chromosomes. In addition to major NORs, two minor loci have been physically mapped at the centromeric regions of chromosomes of group 1 in Vicia amphicarpa, Vicia macrocarpa and V. sativa, and two NORs of group 5 in V. hybrida, and on the long arms of group 4 in V. bithynica. Two or four 5S rDNA loci, observed in the short arms of groups 2–4 and 5, and 18S-26S rDNA loci were located in different chromosomes of all the species within the Narbonensis and Villosa species complexes, and Vicia angustifolia of the Sativa species complex. In the remaining six species of the Sativa species complex, and V. bithynica and V. hybrida, the two or four 5S rDNA sites were present in chromosomes which harbor 18S-26S rRNA genes. The tandemly repeated 5S rDNA sites, located at the proximal part of the long arm of groups 3–5, were diagnostic for V. angustifolia, Vicia cordata, Vicia incisa, V. macrocarpa, Vicia nigra and V. sativa of the Sativa species complex. In V. amphicarpa of the same complex, the tandem repeats were located at the distal part of the long arms of group 3. Variability in the number, size and location of two ribosomal DNA probes could generally distinguish species within the Narbonensis and Sativa species complex, V. bithynica and V. hybrida. With respect to the four species of the Villosa species complex the karyotypes could not be identified individually on the basis of the distribution of two ribosomal gene families in three out of seven pairs of chromosomes.

Osmoprotection mechanisms in rhizobia isolated from Vicia faba var. major and Cicer arietinum

La recherche des mecanismes impliques dans l'osmoprotection chez deux souches de rhizobium isolees des nodosites de Vicia faba var. major et une souche nodulant Cicer arietinum, a montre que la glycine betaine et la choline ameliorent la croissance bacterienne sous stress salin. Lors d'etudes metaboliques, la choline intracellulaire radioactive est transformee en glycine betaine et ce independamment de l'osmolarite du milieu. En effet, les activites choline deshydrogenase et glycine betaine aldehyde deshydrogenase ne sont pas modifiees par le sel. Neanmoins, la presence de la choline dans le milieu augmente les deux activites enzymatiques. L'incubation en presence de la glycine betaine durant une heure est suivie d'une accumulation de ce compose chez les cellules cultivees a 0,15 M NaCl. Cette accumulation n'a plus lieu quatre heures plus tard. Des experiences de croissance avec la glycine betaine ou ses metabolites montrent son utilisation comme source de carbone et d'azote. La recherche, par chromatographie en phase liquide a revele l'accumulation du glutamate et de l'alanine a des niveaux variables en fonction de la souche et du degre de stress.

Behaviour of the adult seven spot ladybird, Coccinella septempunctata (Coleoptera: Coccinellidae), in response to dimethoate residue on bean plants in the laboratory.

The sub-lethal effects of dimethoate residue on the distribution and locomotor activity of adults of Coccinella septempunctata Linnaeus on Vicia faba plants were investigated in the laboratory. The presence of dimethoate residues on the upper half of the plant caused C. septempunctata to spend significantly less time on the plants overall. When given a choice of treated and untreated surfaces, C. septempunctata spent proportionately more time on the untreated areas of the plant. The locomotor activity of C. septempunctata was also altered following encounter with dimethoate residues resulting in a significant increase in the proportion of time spent walking and a reduction in the proportion of time spent resting. The proportion of time spent on plant parts was also affected, with a reduction in the time spent on the apex and an increase in the proportion of time spent on the stem, indicating a possible avoidance response. The proportion of time spent on the adaxial leaf surface was significantly increased following dimethoate treatment. The implications for integrated pest management are considered.

Pre-selection of Rhizobium leguminosarum bv. viceae stains in forage vetch for use as green manure.

The growing enphasis in sustainable agriculture nitrogen fertilization using organic materials motivates the study of improved nitrogen availability in vetch (Vicia benghalensis) grown in alluvial soils of central Chile. With the aim of providing alternatives to artificial N sources, the present research analyzes symbiotic N studies aimed to optimize the contribution of N fixation as a means of attaining stability of N mineralization from organic materials in the soil. Greenhouse trails were made using central zone alluvial soils and native strains of Rhizobium leguminosarum bv. viceae. Strains were characterized by isolation in YEM medium and by determination antibiotics resistance profiles and plasmid profiles using DNA electrophoresis. Plants were grown under controlled environmental conditions in pots with selected soils. The behavior of different rhizobium strains was compared to uninoculated treatments with and without N-fertilizer. DM production (aerial and root), N-accumulation by the plants, nodulation, nitrogenase enzyme activity and ureides content, were superior (p = 0.05) for strain 3. The results support further strain 3 experimentation under field conditions.Debido a la importancia creciente del uso de abonos verdes para aportar nitrogeno (N) a los cultivos en la modalidad de la agricultura sustentable, se estimo necesario estudiar la posibilidad de optimizar la nutricion nitrogenada de vicia (Vicia benghalensis) en suelos aluviales de la zona central. Los estudios tuvieron como objetivo optimizar el aporte de N, incentivando la fijacion simbiotica, a fin de sustituir la fertilizacion nitrogenada al alcanzar la estabilizacion del sistema de mineralizacion de N de los residuos organicos del suelo. Se emplearon suelos aluviales de la zona central, y se caracterizaron cepas nativas de Rhizobium leguminosarum bv. viceae, a traves de aislamiento sobre medio YEM, determinacion de perfiles de resistencia a antibioticos y de plasmidos por electroforesis de ADN, con el objeto de realizar, en una primera etapa, estudios en invernadero. Posteriormente, se establecieron las plantas en macetas con los suelos seleccionados, bajo condiciones ambientales controladas. Se probo el comportamiento de diferentes cepas rizobianas frente a testigos no inoculados con y sin aporte de N fertilizante. Los resultados de produccion de materia seca de la parte aerea y raiz, el N acumulado por las plantas, la nodulacion, la actividad de la enzima nitrogenasa y el contenido de ureidos, fueron significativamente superiores (p=0.05) con la cepa 3 en los parametros de fijacion empleados, lo que permitiria utilizarla en experimentos validatorios en terreno.

Effects of inoculation with Azospirillum brasilense on chickpeas (Cicer arietinum) and faba beans (Vicia faba) under different growth conditions

Les effets de l'inoculation des pois chiches et des feves avec Azospirillum brasilense souche Cd ont ete etudies dans differentes conditions de croissance. Dans les experiences en serre avec les deux legumineuses, l'inoculation avec A. brasilense a augmente de facon significative la nodulation par les rhizobia indigenes et ameliore le developpement des racines et des tiges comparativement a des temoins non inocules. De plus, il a ete montre que le traitement bacterien reduit de facon significative les effets negatifs sur la croissance des plantes dus a l'irrigation avec de l'eau salee. Dans les experiences au champ, l'inoculation des pois chiches avec A. brasilense incorpore a de la tourbe a permis egalement un accroissement significatif de la nodulation, de la croissance des racines et des tiges et du rendement de la culture comparativement a un temoin non inocule.