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.     

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.     

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.     

Reduced height (Rht) and photoperiod insensitivity (Ppd) allele associations with establishment and early growth of wheat in contrasting production systems

Near isogenic lines (NILs) varying for genes for reduced height (Rht) and photoperiod insensitivity (Ppd-D1a) in a cv. Mercia background (rht (tall), Rht-B1b, Rht-D1b, Rht-B1c, Rht8c + Ppd-D1a, Rht-D1c, Rht12) were compared at one field site but within contrasting (‘organic’ vs. ‘conventional’) rotational and agronomic contexts, in each of 3 years. In the final year, further NILs (rht (tall), Rht-B1b, Rht-D1b, Rht-B1c, Rht-B1b + Rht-D1b, Rht-D1b + Rht-B1c) in both Maris Huntsman and Maris Widgeon backgrounds were added together with 64 lines of a doubled haploid (DH) population [Savannah (Rht-D1b) × Renesansa (Rht-8c + Ppd-D1a)]. Assessments included laboratory tests of germination and coleoptile length, and various field measurements of crop growth between emergence and pre jointing [plant population, tillering, leaf length, ground cover (GC), interception of photosynthetically active radiation (PAR), crop dry matter (DM) and nitrogen accumulation (N), far red: red reflectance ratio (FR:R), crop height, and weed dry matter]. All of the dwarfing alleles except Rht12 in the Mercia background and Rht8c in the DHs were associated with reduced coleoptile length. Most of the dwarfing alleles (depending on background) reduced seed viability. Severe dwarfing alleles (Rht-B1c, Rht-D1c and Rht12) were routinely associated with fewer plant numbers and reduced early crop growth (GC, PAR, DM, N, FR:R), and in 1 year, increased weed DM. In the Mercia background and the DHs the semi-dwarfing allele Rht-D1b was also sometimes associated with reductions in early crop growth; no such negative effects were associated with the marker for Rht8c. When significant interactions between cropping system and genotype did occur it was because differences between lines were more exaggerated in the organic system than in the conventional system. Ppd-D1a was associated positively with plant numbers surviving the winter and early crop growth (GC, FR:R, DM, N, PAR, height), and was the most significant locus in a QTL analysis. We conclude that, within these environmental and system contexts, genes moderating development are likely to be more important in influencing early resource capture than using Rht8c as an alternative semi-dwarfing gene to Rht-D1b.     

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.     

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.     

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.     

The identification of faba bean (Vicia faba L.) trisomics by translocation tester set

Summary Five subtelocentric primary trisomics of Vicia faba L. were isolated from crosses between asynaptic mutants and normal plants or translocation tester stocks. The extra chromosome of each trisomic was identified cytologically by critical multivalent association at metaphase I of meiosis.     

Inheritance of trichomes and resistance to pod borer (Helicoverpa armigera) and their association in interspecific crosses between cultivated pigeonpea (Cajanus cajan) and its wild relative C. scarabaeoides

The legume pod borer, Helicoverpa armigera, is one of the most devastating pests of pigeonpea. High levels of resistance to pod borer have been reported in the wild relative of pigeonpea, Cajanus scarabaeoides. Trichomes (their type, orientation, density and length) and their exudates on pod wall surface play an important role in the ovipositional behavior and host selection process of insect herbivores. They have been widely exploited as an insect defense mechanism in number of crops. In the present investigation, inheritance of resistance to pod borer and different types of trichomes (A, B, C and D) on the pod wall surface in the parents (C. cajan and C. scarabaeoides) and their F₁, F₂, BC₁ (C. cajan × F₁), and F₃ generations has been studied. Trichomes of the wild parents (high density of the non-glandular trichomes C and D, and glandular trichome B and low density of glandular trichome A) were dominant over the trichome features of C. cajan. A single dominant gene as indicated by the segregation patterns individually will govern each trait in the F₂ and backcross generation. Segregation ratio of 3 (resistant): 1 (susceptible) for resistance to pod borer in the F₂ generation under field conditions was corroborated with a ratio of 1:1 in the backcross generation, and the ratio of 1 non-segregating (resistant): 2 segregating (3 resistant: 1 susceptible): 1 non-segregating (susceptible) in F₃ generation. Similar results were obtained for pod borer resistance under no-choice conditions. Resistance to pod borer and trichomes associated with it (low density of type A trichome and high density of type C) are governed individually by a dominant allele of a single gene in C. scarabaeoides. Following backcrossing, these traits can be transferred from C. scarabaeoides into the cultivated background.     

Improvement of seed yield in Vicia faba L. By using experimental mutagenesis. II. Comparison of gamma-radiation and ethyl-methane-sulphonate (EMS) in production of morphological mutants

Summary Gamma-rays and EMS have been used in two dosages to test their effectiveness in inducing mutations in one major (cv. Aguadulce) and one minor (cv. Manfredini) Vicia faba cultivar. The plants of the M₁ and M₂ generations showed reduced emergence, survival, and fertility. EMS was more effective than gammarays in inducing mutations giving a mutation frequency in M₁ and a frequency of M₂ mutants from two to four times higher. The two mutagenic agents do not seem to differ in mutation spectrum. The minor cv. Manfredini was more sensitive to the lower dosage of gamma-rays than the major cv. Aguadulce. Both mutagens proved to be effective in enlarging the morphological variation of both cultivars.Research work supported by C.N.R. special grant I.P.R.A.-Sub-project 1. Paper N. 515.     

Cytogenetic analyses of sugarcane relatives (Andropogoneae: Saccharinae)

Summary Meiosis was studied in 31 wild Saccharum relatives, including Erianthus (8 clones), Miscanthus (5 clones), Narenga prophyrocoma (1 clone), S. robustum (3 clones), and S. spontaneum (14 clones). Chromosome number for 18 clones confirmed published counts or was typical of the particular species. Chromosome number for seven clones (Djatiroto 2n=58, Molokai 5099 2n=80, SES 84/58 2n=58, SES 114 2n=64, SES 260 2n=64, Taiwan 100 2n=112, and US 57-11-2 2n=60) differed from published counts (2n=112, 86-100, 64, 60, 60, 96, and 30, respectively). Counts were obtained for the first time for six clones (Local escape 2n=96, Nepal 2n=72, NG 77-77 2n=108–112, NG 77-199 2n=166, US 57-60-2 2n=20, and US 68-1-4 2n=38). Bivalent chromosome pairing predominated in all clones. Meiotic irregularity (numeric aberrations, univalents, multivalents, and telophase II micronuclei) tended to be associated with taxonomic grouping and level of polyploidy. Clones in Erianthus, Miscanthus, and Narenga were apparent euploids (2n=20–60) and tended to have fewer meiotic irregularities than Saccharum clones. Differences in level of meiotic stability among taxonomic groups may reflect error in chromosome association and synapsis associated with high chromosome number.     

Karyotype analysis and interspecific hybridisation in three perennial Sesbania species (Leguminosae)

Summary The somatic chromosome number in Sesbania sesban var. nubica, S. goetzei and S. keniensis (Leguminosae; Papilionoidae) was found to be 2n=12. These findings were in agreement with earlier reports on S. sesban and S. keniensis. The chromosome number 2n=12 is a new record for S. goetzei. Similarities in karyotypes were found in the three species. All species had one pair of long metacentric chromosomes; the second pair was submedian, followed by four smaller pairs of metacentric chromosomes. Nucleolar organiser regions in the form of satellites were found on the short arm of the fourth chromosome pair in S. sesban and S. keniensis. Interspecific crosses in all possible combinations were carried out, resulting in pod and viable seed formation for the crosses S. sesban x S. goetzei, S. sesban x S. keniensis, S. goetzei x S. sesban and S. goetzei x S. keniensis. The two crosses with S. keniensis as a female parent were unsuccessful. The hybrid plants established normally and produced viable seeds.     

Identification of self-incompatibility (S) alleles in Latvian and Swedish sweet cherry genetic resources collections by PCR based typing

The Latvian and the Swedish sweet cherry (Prunus avium L.) genetic resources collections comprise valuable material for breeding. The collections represent local Latvian and Scandinavian genetic resources: semi-wild samples, landraces, and cultivars developed in local breeding programmes, as well as diverse germplasm from the northern temperate zone. The objective of this investigation was to determine which S ₁ –S ₆ alleles are most important in the sweet cherry genetic resources collections and to compare the identified allelic and genotypic frequencies in material of different origin. Accessions in the two collections were screened for the presence of the self-incompatibility (S) S ₁ to S ₆ alleles, using PCR based typing. Significant differences (P < 0.05) between screened collections were found in frequencies of S ₄ and S ₅ alleles. Analysis of allele combinations identified the high occurrence of selections with the S-genotype S ₃ S ₆ in both collections. Compared to the S-allele frequencies published for over 250 sweet cherry cultivars from Western and Southern Europe, the Latvian and Swedish germplasm appeared to have a high frequency of the S ₆ allele in both collections, and a relatively high frequency of the S ₅ allele in Latvian germplasm. This study represents the first comprehensive S-allele screening for the sweet cherry genetic resources collections in Latvia and Sweden. Both sweet cherry collections contain high proportion of accessions adapted to north central European growing conditions, not typical for the majority of the documented sweet cherry genetic resources, which explains differences in certain S-allele occurrence.     

Effect of hardening on frost tolerance and fatty acid composition of leaves and stems of a set of faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.) genotypes

Frost tolerance is a main component of winter-hardiness and improving it would promote faba bean (Vicia faba L.) cropping in cool-temperate regions. In many species, leaf fatty acid composition was found to be related to frost tolerance. The objective of this study was to determine, in a representative sample of genotypes, the effect of hardening on leaf and stem (1) frost tolerance and (2) fatty acid composition, and to seek correlations between them. First leaf, second leaf and stem of 31 faba bean genotypes were analyzed after hardening and without hardening. High frost tolerance of known winter genotypes and several experimental lines was shown. Hardening had a significant, positive effect on frost tolerance of all three organs. Stems were on average more frost tolerant than leaves. Hardening induced significant changes in the fatty acid composition: oleic acid decreased significantly in leaves by 3.24% and in stems by 1.77%, whereas linolenic acid increased in leaves by 6.28% and in stems by 9.06%. In stems, correlations between frost tolerance and fatty acid composition were not significant. Correlation coefficients strongly indicated that non-hardened oleic acid content, changes in oleic acid and in linoleic plus linolenic acid content in leaves partly explained their frost tolerance; 0.347 (P < 0.1) < |r| < 0.543 (P < 0.01). The results corroborate the importance of using genetic differences in the fatty acid metabolism in breeding grain legumes for frost tolerance.     

Progenies of allotriploids of Oriental × Asiatic lilies (Lilium) examined by GISH analysis

With the aim of utilizing allotriploid (2n = 3x = 36) lily hybrids (Lilium) in introgression breeding, different types of crosses were made. First, using diploid Asiatic lilies (2n = 2x = 24), reciprocal crosses (3x − 2x and 2x − 3x) were made with allotriploid hybrids (AOA) obtained by backcrosses of F₁ Oriental × Asiatic hybrids (OA) to Asiatic cultivars (A). Secondly, the AOA allotriploids were crossed with allotetraploid (OAOA, 2n = 4x = 48), in 3x − 4x combination. Finally, the AOA allotriploids where crossed to 2n gamete producer F₁ OA hybrids (3x − 2x (2n)). Two types of triploids were used as parents in the different types of crosses, derived from: (a) mitotic polyploidization and (b) sexual polyploidization. Ploidy level of the progeny was determined by estimating the DNA values through flowcytometry as well as chromosome counting. The aneuploid progeny plants from 3x − 2x and reciprocal crosses had approximate diploid levels and in 3x − 4x crosses and 3x − 2x (2n) the progeny had approximate tetraploid levels. Balanced euploid gametes (x, 2x and 3x) were formed in the AOA genotypes. Recombinant chromosomes were found in the progenies of all crosses, except in the case of 2x − 3x crosses through genomic in situ hybridization (GISH) analyses. Recombinant chromosomes occurred in the F₁ OA hybrid when the triploid AOA hybrid was derived through sexual polyploidization, but not through mitotic polyploidization with two exceptions. Those recombinant chromosomes were transmitted to the progenies in variable frequencies.     

Cytogenetic evidence for the origin of teosinte (Zea mays ssp. Mexicana)

Summary Cytogenetic evidence has shown that teosinte (Zea mays ssp. mexicana (Schrad.) Iltes) and maize (Zea mays L. ssp. mays) are conspecific. They hybridize readily and their offspring are generally fertile. Teosinte could not have originated as a byproduct of maize-Tripsacum hybridization. Such introgression gave rise to plants that are phenotypically maize or Tripsacum, depending on which parent was used as a pollen donor. Compartive morphological and genetical studies indicated that it is more probable that maize originated from a teosinte-like ancestor under domestication, than that a maize-like plant gave rise to teosinte through a series of mutations.Reseach supported financially by the Illinois Agricultural Experiment Station, and Grants GB-40136-X and BM573-01034 A02 from the National Science Foundation.     

Some observations on the origin and evolution of the winged bean (Psophocarpus tetragonolobus)

Summary On the basis of phytogeographic evidence it is suggested that Psophocarpus tetragonolobus has an African ancestry, a possible parallel with the origin of guar (Cyamopsis tetragonoloba) is suggested. The most probable ancestral species is Ps. grandiflorus native to East Africa from Ethiopia to Zaire. This hypothesis could be tested by experimental hybridization between the cultigen and its closest wild relative Ps. grandiflorus.     

Genetic and molecular analysis of the restoration of fertility ( Rf ) genes for Ogura male-sterility from a Japanese wild radish ( Raphanus sativus var. hortensis f. raphanistroides Makino)

Ogura male-sterile cytoplasm is one of the most extensively studied cytoplasms in Brassicaceae. In this study, in order to gain better understanding of the variation and evolution of the restoration of the fertility (Rf) gene for Ogura male-sterile cytoplasm, the nucleotide sequence of the orf687 homologue in the Japanese wild radish (Raphanus sativus var. hortensis f. raphanistroides Makino) was analyzed using an F₂ population made with a cross between a Japanese wild radish plant containing the Rf gene and ‘Uchiki-Gensuke’ (a maintainer of Ogura-male sterility). Segregation of male-fertile/-sterile plants in the F₂ generation suggested that another unidentified Rf gene unlinked to orf687 exists in the Japanese wild radish. The genotype of orf687 was determined for each F₂ plant by Southern hybridization with an orf687 gene probe, mismatch-specific endonuclease digestion of PCR products, and direct sequencing of a PCR product. Genotyping revealed that some fertility-restored plants are homozygotic for the ‘Uchiki-Gensuke’ type orf687 allele, supporting the idea that another gene different from orf687 also functions as an Rf gene for Ogura male-sterility. Protein analysis using an antibody raised against the Ogura-specific ORF138 protein suggests a mechanism of fertility restoration by the unidentified Rf similar to that by orf687. Sequence analysis of orf687 from a Japanese wild radish plant and ‘Uchiki-Gensuke’ revealed that both orf687 regions encode a mitochondrially-targeted protein consisting of 687 amino acids with 16 PPR motifs. Comparison of the deduced amino acid sequences with those of the known orf687 sequences from ‘Yuan hong’ and ‘Kosena’ containing Rf and recessive one (rf), respectively, showed that three unique amino acid replacements are present in ORF687 of the Japanese wild radish. Two of the three replacements, that from lysine to isoleucine at position 232 and from asparagine to asparate at position 240, confer negative charges to the protein. Since the Rf of ‘Yuan hong’ was reported to have a unique replacement that confers a negative charge to ORF687 (from asparagine to aspartate at position 170), it is proposed that the amino acid replacements conferring a negative charge to ORF687 are important for determining the status of the Rf/rf gene.     

The reproductive biology of three perennial Sesbania species (Leguminosae)

Summary The reproductive biology of Sesbania sesban, S. goetzei and S. keniensis (Leguminosae; Papilionoideae) was studied. Fifty percent flowering was observed at 102 to 153 days after germination for S. sesban accessions; 96 to 146 days for S. goetzei and 131 to 176 days for S. keniensis accessions. Flowers opened in the afternoon and remained fresh for 2–3 days. Bee species including Xylocopa sp., Apis mellifera, Megachile bituberculata and Chalicodoma sp. visited the flowers. Hand pollination experiments showed that all three species were self and cross compatible. The percentage of fully developed seeds was greater in pods formed after cross pollination compared to self pollination. No evidence was found for stigmatic or stylar self incompatibility. Outcrossing is probably the common method of reproduction under natural conditions, although in isolated trees substantial seed set by selfing might occur. Pod production under natural conditions was 34% for S. sesban; 49% for S. goetzei and 39% for S. keniensis. Considerable variation was found in pod production under open pollination between accessions of the same species. Selective abortion was observed within pods, with more mature seeds formed at the distal end of the pod.