Andean Origin Research Articles

Structure of genetic diversity among common bean (Phaseolus vulgaris L.) varieties of mesoamerican and andean origins using new developed microsatellite markers

Structure of genetic diversity among common bean (Phaseolus vulgaris L.) varieties of mesoamerican and andean origins using new developed microsatellite markers

What Is the Origin of the European Potato? Evidence from Canary Island Landraces

The modern cultivated potato (Solanum tuberosum L.) was first recorded in Europe in the Canary Islands in 1567, but its origin has long been in dispute. Two competing hypotheses have proposed an “Andean” area (somewhere from the Andean uplands from Venezuela to northern Argentina) or a lowland south-central “Chilean” area, but the Andean origin hypothesis is today generally accepted. The identity of extant Canary Island potato landraces as exclusively of upland Andean origin is one part of a multicomponent argument that the European potato originated from there, rather than from Chile. We reassess these two competing hypotheses with nuclear microsatellite and chloroplast DNA analyses of 19 Canary Island landraces, 14 Andean landraces, 11 Chilean landraces, and two wild potato species as outgroups, and with chloroplast DNA data of 150 landraces from South America. Our molecular results document a wide variation of Andeanߚ and Chilean-type cultivars on the Canary Islands and possible hybrids of the two. Our new data, integrated with historical, molecular, agronomic, and crossing data, support a hypothesis that there were multiple introductions of Andean and Chilean germplasm to the Canary Islands and that the early European potato was selected from Chilean introductions long before the late blight epiphytotics of the 1840s.

Structure of genetic diversity among common bean (Phaseolus vulgaris L.) varieties of Mesoamerican and Andean origins using new developed microsatellite markers

A common bean genomic library was constructed using the ‘IAC-UNA’ variety enriched for (CT) and (GT) for microsatellite motifs. From 1,209 sequenced clones, 714 showed microsatellites distributed over 471 simple and 243 compound motifs. GA/CT and GT/CA were the most frequent motifs found among these sequences. A total of 123 microsatellites has been characterized. Out of these, 87 were polymorphic (73.7%), 33 monomorphic (26.8%), and 3 (2.4%) did not amplify at all. In a sample of 20 common bean materials selected from the Agronomic Institute Germplasm Bank, the number of alleles per locus varied 2–9, with an average of 2.82. The polymorphic information content (PIC) of each marker varied from 0.05 to 0.83, with a 0.45 average value. Cluster and principal coordinate analysis of the microsatellite data were consistent with the original assignment of the germplasm accessions into the Andean and Mesoamerican gene pools of common bean. Low polymorphism levels detected could be associated with the domestication process. These microsatellites could be a valuable resource for the bean community because of their use as new markers for genetic studies.

Genetic architecture of chalcone isomerase non-coding regions in common bean (Phaseolus vulgaris L.)

Sequence data for 2 non-coding regions of the chalcone isomerase gene were analyzed to study the genetic architecture of common bean (Phaseolus vulgaris L.). One region corresponded to the first 596 nucleotides (nt) of the 5'-untranslated region (UTR). The other region was the 710 nt intron 3. Data were collected from 67 genotypes representing both landraces and cultivars from the geographical range of the cultivated form of the species. Variability in the 5'-UTR region was represented by single nucleotide polymorphisms (SNPs), whereas intron 3 variation was due to a collection of SNPs and insertion-deletion events. Diversity was greater in the 5'-UTR (pi = 0.0175) than in intron 3 (pi = 0.0089). For each region, diversity was greater for genotypes of Middle American than Andean origin. A single recombination event was observed, and the hybridization pattern necessary to derive the recombinant genotypes supported the previous observation of an ancestral gene pool from which modern domesticated genotypes are derived. For both regions, a strongly supported Andean group was observed, whereas the presence of 2 Middle American subgroups was also supported. Although a significantly positive Tajima's D statistic was observed for the 5'-UTR for all genotypes, we conclude that this is more likely the result of a strong demographic effect and that balancing selection is occurring only among the Middle American genotypes.

Disputing Limeño Historical and Cultural Heritage

In the 1970s many persons of andean origin migrated to Lima. Informally and through the mediation of emerging grassroots organizations, the nuevos limeños negotiated with the state for their right to residency in the city and to sanitation and other services. They struggled for recognition as citizens. Gradually an informal economy mainly based on Andean cultural practices of production gave way to entrepreneurship, which created a new middle class. In this way Andean migrants to Lima became urban workers and consumers and appropriated and transformed the city.

A genetic linkage map of Phaseolus vulgaris L. and localization of genes for specific resistance to six races of anthracnose (Colletotrichum lindemuthianum)

A genetic map of common bean was constructed using 197 markers including 152 RAPDs, 32 RFLPs, 12 SCARs, and 1 morphological marker. The map was established by using a F(2) population of 85 individuals from the cross between a line derived from the Spanish landrace Andecha (Andean origin) and the Mesoamerican genotype A252. The resulting map covers about 1,401.9 cM, with an average marker distance of 7.1 cM and includes molecular markers linked to disease resistance genes for anthracnose, bean common mosaic virus, bean golden yellow mosaic virus, common bacterial blight, and rust. Resistance to races 6, 31, 38, 39, 65, and 357 of the pathogenic fungus Colletotrichum lindemuthianum (anthracnose) was evaluated in F(3) families derived from the corresponding F(2) individuals. The intermediate resistance to race 65 proceeding from Andecha can be explained by a single dominant gene located on linkage group B1, corresponding to the Co-1 gene. The recombination between the resistance specificities proceeding from A252 agrees with the assumption that total resistance to races 6, 31, 38, 39, 65, and 357, is organized in two clusters. One cluster, located on B4 linkage group, includes individual genes for specific resistance to races 6, 38, 39, and 357. The second cluster is located on linkage group B11 and includes individual genes for specific resistance to races 6, 31, 38, 39, and 65. These two clusters correspond to genes Co-3/Co-9 and Co-2, respectively. It is concluded that most anthracnose resistance Co- genes, previously described as single major genes conferring resistance to several races, could be organized as clusters of different genes conferring race-specific resistance.

Temporal changes in genetic diversity of common bean (Phaseolus vulgaris L.) accessions cultivated between 1800 and 2000

Fourteen microsatellite markers were used to describe genetic diversity in a sample of 128 common bean (Phaseolus vulgaris L.) accessions cultivated within the territory of Slovenia and its nearby regions between 1800 and 2000. The accessions were grouped into three periods, Period I comprising accessions from the beginning of the 19th century, while the other two periods included accessions from the middle (Period II) and the end of the 20th century (Period III). Seven control accessions of known Mesoamerican and Andean origin were also included in the study. A total of 130 alleles were generated. Allelic richness, in terms of number of alleles per locus, was 6.07 for Period I, 6.71 for Period II and 6.07 for Period III. In the UPGMA dendrogram, all studied accessions were intermixed in three main clusters, indicating that the diversity in the time periods overlapped. Two clusters consisted of accessions of Andean and Mesoamerican origin, while the third represents additional variation, which existed in this area already 200 years ago. The analysis of molecular variance showed that a great part of genetic diversity has been preserved till today, confirming the results of cluster analysis. The calculation of number of alleles per locus revealed no significant quantitative change in genetic diversity over the last 200 years of common bean cultivation. However, the calculation of genetic distances indicated slight qualitative shifts in genetic diversity of common bean germplasm over time, while the calculations of allelic frequency variation and polymorphic information content revealed recent decline of some alleles' frequencies. These findings should stress the need for establishing an appropriate strategy of genetic resources management.

Molecular characterization of Phaseolus vulgaris L. genotypes included in Bulgarian collection by ISSR and AFLP™ analyses

Seventy-eight (33 Bulgarian and 45 foreign) common bean (Phaseolus vulgaris L.) genotypes included in Bulgarian collection were screened for ISSR (Inter Simple Sequence Repeats) and AFLP™ (Amplified Fragment Length Polymorphism) markers. ISSR analysis was performed with 13 primers, and 55 (36.7 %) out of the 150 bands observed were polymorphic. One hundred and sixty-four AFLP™ fragments were obtained with three primer combinations, of which 54 (32.9%) were polymorphic. UPGMA (Unweighted Pair Group Method Arithmetic Averages) analysis was performed using DICE coefficient and dendrograms were constructed using either the data from each method (ISSR and AFLP™) separately or combined in a single joint matrix. Despite some genetic heterogeneity observed in both pools (Middle American origin: M and Andean origin: A) the genotypes were separated in to main groups: one gathering genotypes mainly from pool M and the other more genotypes from pool A. Moreover, Bulgarian genotypes were spread over the two groups suggesting that they are not subject to genetic erosion and that the Phaseolus genetic diversity is conserved.

Genetic Diversity and Origin of Slovene Common Bean (Phaseolus vulgaris L.) Germplasm as Revealed by AFLP Markers and Phaseolin Analysis

There is a long tradition of common bean cultivation in Slovenia, which has resulted in the development of numerous landraces in addition to newly established cultivars. The genetic diversity of 100 accessions from the Genebank of the Agricultural Institute of Slovenia (AIS) were evaluated with amplified fragment length polymorphism (AFLP) markers and phaseolin seed protein. Twenty-seven standard accessions of known Mesoamerican and Andean origin, 10 wild Phaseolus vulgaris accessions and two related species, P. coccineus L. and P. lunatus L., were also included. Ten AFLP primer combinations produced 303 polymorphic bands, indicating a relatively high level of genetic diversity. Based on the marker data, unweighted pair group method with arithmethic mean (UPGMA) analysis and principal coordinate analysis (PCoA) all P. vulgaris accessions were separated into three well-defined groups. Two groups consisted of accessions of Mesoamerican and Andean origin, while the third was comprised of only four wild P. vulgaris accessions. A set of Slovene accessions formed a well-defined sub-group within the Andean cluster, showing their unique genetic structure. These data were supported by phaseolin analysis, which also revealed additional variants of “C” and “T” phaseolin types. The results are in agreement with previous findings concerning diversification of common bean germplasm introduced in Europe.

Genetic diversity of Phaseolus vulgaris L. and P. coccineus L. landraces in central Italy

AbstractThe genetic diversity of 66 Phaseolus genotypes was investigated, which included 14 local varieties of Phaseolus vulgaris and nine local varieties of P. coccineus, collected in Marche, central Italy. Their genetic diversity was assessed using three types of molecular marker: inter simple sequence repeats (ISSRs), nuclear gene‐tagged simple sequence repeats (SSRs) and chloroplast simple sequence repeats (CpSSRs). Phaseolus vulgaris shows a higher genetic diversity than P. coccineus for the SSRs and CpSSRs, but not for the putative neutral ISSR markers. These data suggest that selection by farmers and adaptation to heterogeneous environments has maintained the diversity in landraces of the common bean. Comparing genetic diversity in Marche with that of the American controls reveals that 71% of the local P. vulgaris varieties in Marche are of Andean origin. The two gene pools of the common bean can be found on the same farm, and there is some evidence of past hybridization events between these two gene pools.

Tracing the origin of Spanish common bean cultivars using biochemical and molecular markers

Fifty-four accessions of Phaseolus vulgaris cultivated in Spain and representing a broad variability for this country, were studied together with 30 samples of wild forms of American origin. Two reference cultivars (from the Andes and Mesoamerica) plus two outgroups (P. coccineus and Vigna unguiculata) were also included. RAPD analysis of DNA leaf extracts were carried out with four selected primers. We also studied morphological characters of the seeds and the phaseolin electrophoretic patterns. Multivariate analysis with the UPGMA method using RAPD data clustered the samples in four groups and, comparing with morphological data and phaseolin types, showed that the Spanish cultivars were mainly of Andean origin. Nevertheless, occurrence of introgression in Spain and the consideration of the country as a second center of variability for beans can also explain the obtained results.

Characteristics of rhizobia nodulating beans in the central region of Minnesota

Until recently, beans (Phaseolus vulgaris L.) grown in Minnesota were rarely inoculated. Because of this, we hypothesized that bean rhizobia collected in Minnesota would either share characteristics identifiable with Rhizobium etli of Mesoamerican or Andean origin, introduced into the region as seed-borne contaminants, or be indigenous rhizobia from prairie species, such as Dalea spp. The latter organisms have been shown to nodulate and fix N2 with Phaseolus vulgaris. Rhizobia recovered from the Staples, Verndale, and Park Rapids areas of Minnesota were grouped according to the results of BOXA1R-PCR fingerprint analysis into 5 groups, with only one of these having banding patterns similar to 2 of 4 R. etli reference strains. When representative isolates were subject to fatty acid - methyl ester analysis and 16S rRNA gene sequence analysis, the results obtained differed. 16S rRNA gene sequences of half the organisms tested were most similar to Rhizobium leguminosarum. Rhizobia from Dalea spp., an important legume in the prairie ecosystem, did not play a significant role as the microsymbiont of beans in this area. This appears to be due to the longer time needed for them to initiate infection in Phaseolus vulgaris. Strains of Rhizobium tropici IIB, including UMR1899, proved tolerant to streptomycin and captan, which are commonly applied as seed treatments for beans. Local rhizobia appeared to have very limited tolerance to these compounds.

GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEAN

GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEAN

RAPD and SCAR Markers Linked to the Ur‐6 Andean Gene Controlling Specific Rust Resistance in Common Bean

Bean rust, caused by Uromyces appendiculatus (Pers.: Pers.) Unger, is a major disease of common bean (Phaseolus vulgaris L.). A recommended strategy to obtain durable rust resistance is to use molecular markers linked to rust resistance genes for pyramiding monogenic resistance genes into a single bean cultivar. However, markers tightly linked to Ur‐6 of Andean origin conferring specific resistance (SR) to rust present in Olathe have not been reported. Our objectives were to identify random amplified polymorphic DNA (RAPD) markers linked to Ur‐6 controlling SR to race 51 using bulked segregant analysis in an F2 population from the Middle American (MA) common bean cross Olathe (resistant) × Nebr.#1 sel.27 (susceptible), and determine the presence or absence of these identified markers in 70 MA and Andean bean cultivars and breeding lines. A single dominant gene controlling SR to race 51 was found in the F2 and confirmed in the F3 Six RAPD markers were detected in a coupling phase linkage with Ur‐6 The gene was flanked by two coupling‐phase markers OBC06.300 and OAG15.300 at 1.3 and 2.0 cM. Sequence characterized amplified region (SCAR) marker SOBC06.308 was developed based on the specific primer pair designed from the sequence of the RAPD marker OBC06.300. The RAPD and SCAR markers were also present in MA pinto bean germplasm having Ur‐6 as well as Golden Gate Wax, another source of Ur‐6 However, these markers were also present in six Andean cultivars without Ur‐6, suggesting gene pool specificity. Among five repulsion‐phase markers identified, OAY15.200 was the most closely linked to Ur‐6 at 7.7 cM. We also confirm the Ur‐6 location on linkage group 11 of the P. vulgaris map. These RAPD and SCAR markers linked to Ur‐6 identified here, along with markers for other independent rust resistance genes, could be utilized to pyramid multiple genes into a bean cultivar for more durable rust resistance.

Reação de cultivares de feijoeiro comum a quatro raças de Phaeoisariopsis griseola

A mancha-angular causada pelo fungo Phaeoisariopsis griseola, apresenta grande importância na cultura do feijoeiro (Phaseolus vulgaris) no Brasil. O desenvolvimento de cultivares resistentes tem sido proposto como maneira eficaz, eficiente e econômica para o controle da doença. Um dos primeiros passos no programa de melhoramento visando resistência à mancha-angular é a identificação e seleção de fontes de resistência. Neste contexto, este trabalho objetivou a caracterização de 58 cultivares de feijoeiro quanto a reação às raças 31.17, 63.19, 63.23 e 63.55 de P. griseola. Os resultados mostraram que as cultivares Antioquia 8 e CAL 143, ambos de origem Andina, e Ecuador 299 e México 235, de origem Mesoamericana, apresentaram resistência às quatro raças testadas. As cultivares A 193 e Golden Gate 416 mostraram resistência a três das quatro raças testadas, podendo também, ser úteis em programas de melhoramento. Dentre as cultivares mais suscetíveis encontram-se as cultivares IPA 7419, AN 9022180, Bambuí, Compuesto Negro Chimaltengo, Guanajuato 10-A-5, Diamante Negro, Early Gallatin, Jamapa e Kentucky Wonder 780 e as cultivares de grãos tipo carioca AN 9022180, Aporé e Carioca 80. As novas fontes de resistência à mancha angular identificadas neste trabalho poderão ser utilizadas por programas de melhoramento do feijoeiro que visem a incorporação de genes de resistência de origem Andina ou Mesoamericana.

Clover Proliferation Group (16SrVI) Subgroup A (16SrVI-A) Phytoplasma is a Probable Causal Agent of Dry Bean Phyllody Disease in Washington.

During 2003, a new disease, dry bean phyllody (DBPh), was observed in the Columbia Basin of Washington in dry bean (Phaseolus vulgaris L.) cultivars of Andean origin grown in Mattawa and Paterson, WA that caused great reduction in dry bean production. Symptoms of DBPh became apparent during mid-to-late pod development and were characterized by leafy petals (phyllody) and aborted seed pods resembling thin, twisted, and corrugated leaf-like structures. Deformed sterile pods that were small, sickle-shaped, upright, and leathery were also observed. The infected plants generally exhibited chlorosis, stunting, or bud proliferation from leaf axils. Symptoms of DBPh were indicative of possible infection by phytoplasmas. Restriction fragment length polymorphism (RFLP) and phylogenetic analyses of amplified 16S rDNA sequences were used for phytoplasma identification. Four symptomatic bean plants were analyzed and tested positive for phytoplasma infection on the basis of results of initial polymerase chain reaction (PCR) and subsequent nested-PCR amplifications (2). RFLP analyses of 16S rDNA sequences with restriction enzymes, MseI, AluI, HhaI, RsaI, and HpaII indicated that the phytoplasma strains associated with DBPh belonged to the clover proliferation group (16SrVI) subgroup A (16SrVI-A) (2). This subgroup currently consists of three members, clover proliferation (CP; GenBank Accession No. AY500130), potato witches'-broom (PWB; GenBank Accession No. AY500818), and vinca virescence (VR; GenBank Accession No. AY500817), a strain of beet leafhopper-transmitted virescence agent (BLTVA) phytoplasmas (1,2). The taxonomic affiliations of the DBPh phytoplasma strains were confirmed by phylogenetic analysis of cloned 16S rRNA gene sequences (GenBank Accession Nos. DBPh2, AY496002; DBPh3, AY496003). Among the existing members of subgroup 16SrVI-A, the four DBPh strains were closely related to the VR strain with 99.7% 16S rDNA sequence homology and to the CP strain with 99.2% sequence homology. To gain further evidence on the role of 16SrVI-A phytoplasma strains in DBPh disease, a modified test of Koch's postulates was conducted. Infected tissue from one phytoplasma-positive dry bean sample was grafted onto three Pinto UI-114 bean seedlings in the greenhouse. Within 60 days, the bean seedlings exhibited corrugated leaf-like structures from aborted seedpods, a lack of flower formation, general chlorosis, and stunting similar to the original diseased plants. The lower leaves of the inoculated bean plants became epinastic and leathery. The transmitted phytoplasma was detected in each of the grafted symptomatic seedlings, and the RFLP patterns of its 16S rRNA gene sequences were identical to those of the phytoplasmas in the scions. A high correlation between the presence of disease symptoms and the presence of subgroup 16SrVI-A phytoplasmas in the bean plants suggests that these phytoplasmas play an etiological role in DBPh disease. To our knowledge, these findings provide the first confirmed case of phytoplasma-associated DBPh in the United States.

Analysis of Pathotypes of Colletotrichum lindemuthianum Found in the Central Region of Mexico and Resistance in Elite Germ Plasm of Phaseolus vulgaris.

The pathotypes of 17 isolates of Colletotrichum lindemuthianum from the central region of Mexico were characterized to determine the genetic relationship among isolates from this region and other regions of Mexico, and to evaluate the resistance present in the elite germ plasm collection of Phaseolus vulgaris at INIFAP. Eight pathotypes were identified, including pathotype 292, which is reported for the first time in Mexico. The lack of isolates infecting cultivar TU carrying the Co-5 resistance gene suggests that this cultivar is a useful source of resistance. Six pathotypes produced susceptible reactions on only differential cultivars of Middle American origin, one pathotype on a single cultivar of Andean origin, and one pathotype on cultivars of both Middle American and Andean origin. Comparison of amplified fragment length polymorphism (AFLP) genotypes of 21 isolates confirmed suggestions that populations of C. lindemuthianum are comprised of asexually reproducing clonal lineages. Analysis of five different pathotypes of C. lindemuthianum on 21 elite genotypes of P. vulgaris identified four genotypes from different races of P. vulgaris resistant to all five pathotypes. This information will allow breeders and farmers to select the resistant genotypes most suited to their needs.

Phytogeographical relations of the Andean dry valleys of Bolivia

AbstractAim The objective of this study is to examine the phytogeographical affinities of the Andean dry valleys of Bolivia in order to contribute to a better understanding of the Andean dry flora's distribution, origin and diversity. Particular emphasis is given to the analysis of the floristic connections of this flora with more austral parts of South America.Location The dry valleys of Bolivia are located in the Andes of the southern half of the country, at elevations between 1300 and 3200 m.Methods An extensive floristic list compiled by the author to evaluate plant diversity in these Andean regions was used as the base for this study. To accomplish this, all recorded genera and species were assigned, respectively, to 11 and 12 phytogeographical elements established previously by the author. Two phytogeographical spectra were thus obtained and analysed.Results At the genus level, the Andean dry valleys of Bolivia are clearly dominated by genera that have widespread distributions (cosmoplitan and subtropical genera). Many of these reached the Andes from the lowland region of the Chaco. At species level, Andean elements constitute more than 60% of the species total, most of which are restricted to the central‐southern Andes. This suggests that Chaco‐related and Andean genera had considerable levels of speciation in these valleys. Many genera and more than half the species have their northernmost distribution in the dry valleys of Bolivia, thereby underlining strong relationships with central‐southern South America (mainly Argentina, Paraguay and southern Brazil). The data supports the belief of the existence, in central‐southern Peru, of a floristic disjunction in dry to arid environments that separates a tropical dry flora north of this limit from a dry subtropical/warm temperate flora south of it.Main conclusions The Andean dry valleys of Bolivia are diverse plant communities with high levels of endemism (c. 18% of the species). The species of this region are more related to those present in central‐southern South America than to the flora of northern South America that ranges southwards to Peru. Many of the species have restricted distributions in the dry Andes of Bolivia and Argentina, and many genera of these dry valleys have their northernmost distribution in Bolivia/southern Peru, too. The data point to high levels of speciation also in the central Andes.

Contributions of the Bean/Cowpea CRSP to management of bean diseases

Diseases are a major constraint to production of beans in developing countries, reducing yields and seed quality. Contributing factors include poor disease management, lack of resistant cultivars, and the limited availability of certified disease-free seed. From the outset the Bean/Cowpea Collaborative Research Support Program (CRSP) has emphasized integrated disease management, and breeding for resistance to bean rust ( Uromyces appendiculatus), common bacterial blight ( Xanthomonas campestris (= X. axonopodis) pv. phaseoli) (CBB) and web blight ( Thanatephorus cucumeris (anamorph Rhizoctonia solani)) (WB). Later in the 1990s, angular leaf spot ( Phaeoisariopsis griseola) (ALS), and virus induced bean common mosaic (BCM) and bean common mosaic necrosis (BCMN) became more widespread and epidemic. The research included development of disease-resistant germplasm and studies of pathogenic variation and epidemiology. During the early 1990s bean golden yellow mosaic (BGYM), became a major disease of common bean in the Caribbean and Central America. No cultivar resistant to the gemini virus causing BGYM was available in the Dominican Republic (DR) and pesticides were used to reduce transmission of the virus by white flies ( Bremisia tabaci) biotype A. A change in the bean-production system to limit reproduction of the vector through a host-free period and concentrate the bean growing season to a four month period reduced BGYM significantly. Improved resistant cultivars and disease management resulted in high yields and self-sufficiency of beans in the DR. Evidence for co-evolution of the pathogens causing ALS, CBB, and rust in the two major bean gene pools (Andean and Middle American) was found. Variation in the WB pathogen on bean indicated independent genetic populations and the presence of different anastosmosis subgroups. WB disease management practices should be designed for the sub-group of the pathogen. Seed transmission was found to be a significant source of R. solani inoculum. Specific ( Ur-9 gene) and adult-plant resistance ( Ur-12 gene) to rust was identified for PC-50 (Andean origin) in the DR, and the genes were mapped. A mobile rust nursery was developed to monitor races of rust in a region and assist in resistance-gene deployment in bean germplasm and varieties. DNA based diagnostic methods were developed to differentiate X. campestris pv. phaseoli from X. campestris pv. phaseoli var fuscans (prevalent in East Africa) and P. griseola isolates. DNA hybridization methods also were developed to identify BGYM and bean golden mosaic viruses. Research in USA and East Africa has helped define bean common mosaic virus (BCMV) and bean common mosaic necrotic virus (BCMNV) as separate viruses and has demonstrated that BCMNV appears to be indigenous to Africa. Serological tools were developed that assist in the detection and identification of potyviruses, BCMV and BCMNV. These tools are now used worldwide.

Sistemática de especies de Lutzomyia del grupo verrucarum Theodor, 1965 (Diptera: Psychodiadae).

The verrucarum group of phlebotomine sand flies includes vectors of Leishmania spp. and Bartonella bacilliformis, and from the perspective of public health is considered as one of the most important groups of neotropical phlebotomine sand flies. Due to marked morphological similarity among species constituting this group, the identification based on conventional taxonomic characters can be difficult. Consequently, the verrucarum group has been the focus of numerous taxonomic comparisons which have included the following methods: chaetotaxy, morphometry, larval spiracular system, chorionic structure, morphology of the genital atrium, cytogenetics, morphological phylogenetics, isoenzymes, random amplified polymorphic DNA, cuticular hydrocarbons, DNA probes, and nuclear and mitochondrial nucleotide sequences. Based on morphological characters of the male terminalia, the verrucarum group has been divided in four series, i.e., verrucarum, serrana, townsendi and pia. Since the revision of the group made by Young and Duncan in 1994, ten new species, principally of Andean origin, have been assigned to 3 of the series verrucarum (L. maranonensis, L. cajamarcensis, L. antioquiensis, L. falcaorum), serrana (L. robusta, L. guilvardae) and pia (L. suapiensis, L. tihuiliensis, L. tocaniensis, L. limafalcaoae). The total number of verrucarum group members is now 40. Explanations for this diversity of species include the isolation of ancestral populations in refugia of humid forest during the quaternary period, the Andean cordilleras as geographical barrier, and the appearance of the Isthmus of Panama. Biology systematics and evolution of the verrucarum group is reviewed with emphasis on the 19 species extant in Colombia.