Symbiotic variability in Vicia faba. 2. genetic variation in Vicia faba

Summary Eight varieties of Vicia faba were examined in association with a standard strain of Rhizobium leguminosarum and also with the application of mineral nitrogen. Large differences in dry matter yield, nitrogen percentage and total nitrogen uptake were apparent between varieties and between rhizobium and mineral nitrogen treatments; the interaction was also significant. Genotypic differences in both the effectiveness of the symbiosis with this strain of rhizobium and the efficiency of utilization of nitrogen were thus demonstrated. The implications of this variability on the assessment of varieties and the possiblity of exploiting it by plant breeding techniques are discussed.     

Pattern analysis and genotypic x environment interactions in faba bean (Vicia faba L.) populations

Summary Twenty-nine populations of faba bean (Vicia faba L. subsp. major, equina and minor) of mediterranean origin were evaluated for the genetic variability of 12 biomorphological characters at four locations in Apulia and Basîli cata regions (Italy) in 1983–84.A pattern analysis appoach, based on classification and ordination procedures is presented for to characterize differences among population in mean performance and response across environments. Informations about G × E interaction were obtained.Research work supported by CNR, Italy. Special grant I.P.R.A. Sub-project 1. Paper N. 1099.     

Rate and inheritance of cross-fertilization in faba bean (Vicia faba L.)

Summary To assess the feasibility for synthetic varieties of Vicia faba L., 108 faba bean genotypes were screened for cross-fertilization rate in five field experiments carried out in 1989 and 1990 at Wageningen.Significant genotypic differences were observed for outcrossing rate, which ranged from 1 to 55%. These percentages, however, are thought to be not high enough for a commercially feasible production of synthetic varieties.The inheritance of cross-fertilization rate, determined by testing the F₄ generation of a cross between two inbreds, both with high outcrossing rates, appeared to be of a polygenic nature, as was indicated by the wide variation in, and the continous distribution of, the cross-fertilization rates. Among the F₄ lines tested some had a significantly higher cross-fertilization rate than the parents. However, this difference was not found when these lines were retested, indicating that possibilities for successful selection for higher outcrossing rates might be limited.     

Maintenance breeding and multiplication of pea and faba bean cultivars. Maintenance of protein peas (Pisum sativum) and field beans (Vicia faba)

Summary The maintenance of protein pea (Pisum sativum)and field bean (Vicia faba)cultivars is a part of the breedingscheme of these pulses at CEBECO-ZADEN. As soon as the cultivar is pure breeding a large quantity ofseed is stored under conditioned circumstances.     

Mutagenesis of faba bean (Vicia faba L.) and the identification of five different genes controlling no nodulation,ineffective nodulation or supernodulation

Summary Mutagenesis ofVicia faba L. using ethyl methanesulfonate has yielded three mutants (f13, f73, f245) with ineffective nodulation (Nod⁺Fix^–), one mutant (f48) unable to nodulate (Nod^–) and one supernodulating mutant (f32) having 3 to 5 times more nodules than the control in the absence of combined nitrogen, and expressing nitrate tolerant nodulation (Nod⁺⁺, Nts). All of the mutant phenotypes were controlled by single and distinct recessive genes designatedsyml tosym5, respectively. Grafting experiments showed that the (Nod⁺Fix^–) and (Nod^–) phenotypes were both under root genotype control and that the (Nod⁺⁺, Nts) phenotype was under shoot genotype control.     

Breeding for wide adaptation in faba bean

Summary Broadening agronomic adaptation will improve yield stability in the grain legume Vicia faba L. We gathered information on the adaptation of European and Mediterranean material to European and Mediterranean environments. The material comprised 20 inbred lines (12 European and 8 Mediterranean lines) and 99 intra- and interpool-crosses in generation F₁. These were evaluated in 9 environments: two spring-sown Southern German environments (SGermE), and seven autumn-sown Mediterranean environments (MedE) in Sicily, Puglia, Andalucia and South Africa. Standard ANOVA, stability analyses and AMMI analysis were performed. Mean yield in F₁ was 257 g/row, the overall parental mean was 144 g/row. The range of environmental means was from 94 g/row to 411 g/row. The average regression coefficient in F₁ was b _i =1.07, being significantly greater than for the parents (b _i =0.68). The opposite was true for the relative magnitude of the deviations from the regressions, which were highly correlated to the AMMI-PC1-results. The AMMI analysis clearly separated the SGermE from the MedE, as well as the germplasm pools. Though the superiority of the F₁-hybrids over their parents was striking, their pattern of interactions with the environments strictly reflected that of their parents. A number of promising crosses was identified as a nucleus of a widely adapted faba bean genepool.     

Symbiotic variability in Vicia faba. 1. Genetic variation in the Rhizobium leguminosarum population

Summary Twenty isolates taken at random from indigenous populations of Rhizobium leguminosarum sampled near Aberystwyth were each inoculated into plants of a standard Vicia faba variety grown aseptically under conditions free of combined nitrogen. Plants in association with the individual rhizobium isolates exhibited large differences in dry matter yield, nitrogen content, efficiency of nitrogen utilization and date of first flower. The implications of these differences to the productivity and reliability of varieties of field beans are discussed.     

Screening faba beans for resistance to Ascochyta fabae by artificial inoculation of seedlings

Summary A method was developed for screening faba bean seedlings for resistance to Ascochyta fabae. Several factors were investigated, including amount and concentration of inoculum, period of high humidity and age of leaves. Seedlings of different cultivars were tested and results compared with available field data. Older leaves proved to be less susceptible than younger leaves. Seedling tests reflected differences in resistance in the field, especially in material uniform in growth habit.     

Evaluation of a collection of faba bean (Vicia faba L.) genotypes originating from the Maghreb for resistance to chocolate spot (Botrytis fabae) by assessment in the field and laboratory

Screening of 136 faba bean lines forresistance to chocolate spot caused by thefungus Botrytis fabae was conductedin field conditions with artificialinoculation. Detached leaves of thesegenotypes were also assessed for diseaseseverity after inoculation under controlledconditions with a B. fabaesuspension. The BPL710 and Aguadulcegenotypes were inserted as resistant andsusceptible checks, respectively. Diseasesymptoms were scored visually in bothexperiments. Diameter of lesions andproduction of spores were measured in thedetached leaf assay. The disease scoreindex and diameter of lesions were used tocalculate the area under the diseaseprogress curve (AUDPC) to measure thedisease progress. Significant differenceswere detected among genotypes for reactionto the disease in the field. However, nocomplete resistance was observed. Forhighly susceptible and highly resistantgenotypes, the laboratory assay generallyled to the same result as the field test,nevertheless, for more intermediate levelsthe agreement was weak. On detached leaves,diameter of lesions was significantlycorrelated to the AUDPC of disease scores(r = 0.89) and moderately correlated tosporulation (r = 0.52). The correlationbetween field AUDPC and detached leaf AUDPCof disease scores was low (r = 0.26). A lowcorrelation was also observed between fieldAUDPC and lesion size (r = 0.30) andbetween field AUDPC and sporulation (r =0.32). Among the 136 genotypes evaluated inthis study, nine were convincingly andhighly resistant in both tests. FRYM167 andFRYA58 genotypes were the most resistantwith low AUDPC of disease scores, low AUDPCof lesion diameter and low sporeproduction. These genotypes obviously havepartial resistance.     

Self-fertility and the distribution of seed yield in Vicia faba L.

Summary Five lines of field beans (Vicia faba L.) bred and selected for a high level of self-fertility have demonstrated heritable differences in distribution of seed yield on the reproductive nodes when grown under conditions of selfpollination. Fully self-fertile genotypes produce a large proportion of the seed yield on the lower nodes. The breeding and selection for both self-fertility and the distribution of seed yield is discussed.     

Note on the presence of the sym-1 gene in Vicia faba hampering its symbiosis with Rhizobium leguminosarum

Summary A symbiotically defective mutant in Vicia faba is described. This character is controlled by a recessive gene named sym-1. Reciprocal graft experiments indicate that only the root system controls its expression. Depending on the strain of Rhizobium, the root phenotype can be either Fix⁺ Nod^- or Nod^-.     

Interspecific hybridization between Vicia faba (L.) and Vicia narbonensis (L.): Early pod growth and embryo-sac development

Summary Fertilized embryo-sac development and pod growth was studied in one Vicia faba cultivar, one Vicia narbonensis population and their reciprocal crosses. The initial development of endosperm and embryo was at least four days faster in V. narbonensis than in V. faba. Pods and ovules developed also faster in V. narbonensis than in V. faba. The growth rate of the hybrid pods followed the growth rate of the mother species, but was slower than that of the pods from selfed flowers. In the cross V. narbonensis × V. faba the ovules stopped growing 9 days after pollination, while in the reciprocal cross they stopped growing 15 days after pollination. Hybrid embryo-sacs from V. faba × V. narbonensis were aborted before they reached the stage of 256 endosperm nuclei or 200 embryo cells. Selfed V. faba embryo-sacs reached this stage in less than 9 days after pollination. In the reciprocal cross the embryo-sacs were aborted before they reached the stage of 128 endosperm nuclei or 80 embryo cells. Selfed V. narbonensis embryo-sacs reached this stage at the 4th day after pollination. Given that at these stages the embryo has less than 200 cells it was concluded that an in-ovule embryo culture technique should be developed to obtain hybrid plants.     

Variation and covariation in Vicia faba L. populations of Mediterranean origins

Summary Variation and covariation in 15 Vicia faba L. ssp. major populations from Italy. Greece and Egypt were analyzed. Ten quantitative morphobiological characters of agronomical and nutritional interest were observed. Differences among countries of origin were highly significant for all characters except for lowest podded node. Phenotypic distances among populations, both within and among origins, estimated on canonical variates evidenced that the Egyptian populations from a distinct group and that a relevant degree of similarity exists among the Greek and the Italian meterial. The covariation structure within populations, which was studied by means of factor analysis, was comparatively simpler in the Egyptian material than in that form the other two Mediterranean countries. The differences evidenced can be attributed to different gene associations between characters and suggest the possibility of obtaining, through recombination, genotypes agronomically more favorable.Research work supported by C.N.R., Italy, special grant. Sub-Project 1, Paper No. 299.     

Controls over pollination and ovule fertilization in Vicia faba

Summary Variation in the frequencies of pollination and ovule fertilization was generated among faba bean (Vicia faba L.) genotypes in experiments which compared self-and open-pollination, natural and extended photoperiods, presence and absence of honey bees and a range of plant populations.There was a near-1:1 relationship between the frequencies of pollination of stigmas and the fertilization of at least one ovule within the pistil. Pollination was the major barrier to fertilization of the pistil, and ovules, since no mechanism was evident in the style to prevent pistil fertilization. The frequency with which single ovules were fertilized in pollinated pistils fell as their distance from the stigma increased, and averaged 83.5% overall.The frequency of pollination was most influenced by the level of autofertility possessed by the genotype, and the activity of pollinators. Provision of honey bees to plants in caged plots showed that high levels of pollination could be achieved under open-pollinated conditions, but this was also influenced by autofertility. Increasing plant population in the field had only a small effect on pollination, but extending photoperiod caused the levels and timing of self-pollination in three genotypes to vary.Large differences were found among genotypes in their early stigma receptivity, that is, the frequency of stigmas found to be pollinated at the erect standard stage, prior to the flower opening and being visited by bees. The implications of early stigma receptivity for producing new cultivars were discussed.     

Cross-fertilization behaviour of some white flowering varieties of Vicia faba

Summary Applying a special design for maximalization of cross-fertilization and using flower colour as a marker, considerable differences in the percentage of cross-fertilization between white flowering Vicia faba varieties were observed. Part of these differences were due to differences in beginning of flowering in white and coloured varieties, part of them proves to be independent of this and, therefore appear to be characteristic for the variety. Interaction between mother and father varieties was absent.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Symbiotic variability in Vicia faba. 3. Genetic effects of host plant,rhizobium strain and of host × strain interaction

Summary Six Vicia faba populations were grown in all possible combinations with six Rhizobium leguminosarum strains in order to estimate the relative importance of the three genetic components of symbiotic variability. Additive genetic effects of host genotype and rhizobium genotype accounted for only 8.9% and 11.8% of the total phenotypic variation. Non-additive variation attriabutable to specific host genotype × rhizobium genotype interactions was by far the largest component of variation and accounted for 73.8% of phenotypic differences. Therefore the greatest improvement in symbiotic nitrogen fixation is likely to arise from simultaneous selection of both symbionts.     

Genetics of resistance to 3 isolates of Ascochyta fabae on Faba bean (Vicia faba L.) in controlled conditions

Summary Genetics of resistance to Ascochyta fabae Speg. in Vicia faba L. was studied with a final objective to develop resistant faba bean varieties to Ascochyta blight. The study was conducted separately on 3 single spore isolates (AF10-2 and AF13-2 from Tunisia and AF4-3 from France) and belonging to different groups of virulence (GV1 and GV2). Important general combining ability (GCA) effects were found especially with isolates AF10-2 and AF4-3. Specific combining ability (SCA), although significant for the 3 isolates, was important only with AF13 -2, but less important than GCA. Additive gene effects were predominant to non-additive effects. Lines 29H and A8817 transmitted to their progenies resistance to the 3 isolates, whereas 14–12 and 19TB conferred resistance to their progenies only with isolates AF13-2 and AF4-3, respectively. In the material studied, resistance was generally controlled by dominant genes but also could be attributed to recessive genes although less frequent. Analysis of segregation in the F2 of 2 crosses between the resistant lines (A8817 and 29H) and the susceptible line (14–12) with isolate AF4-3 revealed dominant monogenic control at the level of leaves in the 2 resistant lines and, in addition, a recessive gene controlling resistance of stems. Non-allelic interactions were occasionally manifested and their origin appeared to be due to line 19TB. A recurrent selection scheme was proposed with the objective to develop improved open-pollination populations and synthetic varieties responding to the objective of the national Tunisian research programme on faba bean.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of faba bean <Emphasis Type="Italic">(Vicia faba</Emphasis> L.) using embryo axes

A system for the production of transgenic faba bean by Agrobacterium-mediated transformation was developed. This system is based upon direct shoot organogenesis after transformation of meristematic cells derived from embryo axes. Explants were co-cultivated with A. tumefaciens strain EHA105/pGlsfa, which harbored a binary vector containing a gene encoding a sulphur rich sunflower albumin (SFA8) linked to the bar gene. Strain EHA 101/pAN109 carrying the binary plasmid containing the coding sequence of a mutant aspartate kinase gene (lysC) from E. coli in combination with neomycinphosphotransferase II gene (nptII) was used as well. The coding sequences of SFA8 and LysC genes were fused to seed specific promoters, either Vicia faba legumin B4 promoter (LeB4) or phaseolin promoter, respectively. Seven phosphinothricin (PPT) resistant clones from Mythos and Albatross cultivars were recovered. Integration, inheritance and expression of the transgenes were confirmed by Southern blot, PCR, enzyme activity assay and Western blot.     

Differential response of Vicia faba L. genotypes to 2, 3, 5-triiodobenzoic acid (TIBA)

Summary Response to application of the growth regulator 2, 3, 5-triiodobenzoic acid (TIBA) was examined in the parents and F₁ progenies of a diallel cross of six inbred lines of Vicia faba. TIBA affected the genotypes differentially but in general gave shorter internodes, reduced apical dominance, increased pod set on the lower nodes and earlier seed maturity.