Line selection for exploiting durum wheat (T. turgidum L. var. durum) local landraces in modern variety development program

Summary Pure line selection for grain yield applied within four durum wheat local landraces (Triticum turgidum L. var durum) was studied in an effort to determine: (i) the agronomic performance of selected line mixtures (bulks) and their value as potential new cultivars, (ii) the effectiveness of pure line selection for grain yield within local landraces and (iii) the correlated selection response of yield components and kernel quality traits. Four local durum wheat landraces were used. Two of them, Mytilini-1 and Mytilini-2 are still cropped in some rural areas of the island Mytilini whereas the other two, Limnos and Mavragani are maintained in the Greek Gene Bank. Following their preliminary evaluation for agronomic performance under current growing conditions, 100 individual plants from each landrace were randomly selected. Selected plants (pure lines) were field evaluated head to row during 1997–98 and 1998–99 growing seasons. Based on grain yield performance, bidirectional selection, high vs low, was practised within each landrace. Thus the five higher yielding lines and their corresponding lower ones from each landrace were identified. Selected lines, with no further progeny testing, were pooled using a balanced seed composite to form the high yielding five line bulk and its respective low counterpart. The resulting 16 bulks (eight high and eight low) along with their four source landraces and two commercial varieties, Mexicalli and Simmeto, used as checks, entered field testing for agronomic performance in two and one location during 1999–00 and 2000–01 growing seasons respectively. Data for grain yield and yield components (1000 kernel weight, number of kernels, and productive tillers) along with kernel quality data (protein content and vitreous) were recorded. Data for grain yield indicated that the landraces studied seemed to be line mixtures, as expected, since they responded to bidirectional phenotypic pure line selection. The high yielding bulks were of interesting agronomic performance, equivalent to or significantly better than that of the commercial checks and are worth further testing as potential cultivars. Selected high bulks of Mytilini 2 landrace significantly outyielded both the source landrace and the commercial checks maintaining the high protein content of the source landrace, which was significantly higher than checks. This performance provides evidence that the within landraces selection of lines combining high grain yield with high protein content seems to be feasible. In conclusion, evidence is presented that genetic variability seems to be available within the landraces studied which could be worth using in breeding programs. Furthermore the simple pure line selection breeding effort undertaken seemed to be effective in developing line bulks with promising performance and worth further testing as potential cultivars.     

Genetic variation and interrelationships of agronomic characters in landraces of bread wheat from southeastern Iran

There is renewed interest in wheat landraces as important sources of genetic variation for agronomic characters. Fifty-three pure lines of bread wheat (Triticum aestivum L.) derived from seven landraces collected from southeastern Iran were used to estimate genetic variation and heritability for 13 developmental and quantitative characters. Path-analysis was used to partition the genetic correlations between grain yield and six grain yield-related traits. Mean values of landraces were also compared with three improved cultivars from California and Iran. Genotypic differences among the landraces and among the pure lines collected from the landraces were highly significant for all characters considered. Compared with the modern cultivars, the landrace genotypes were, on average, later in days to heading and taller than the cultivars but had lower values for number of grains per spike, 1000-grain weight, grain yield and harvest index. Some landrace genotypes were similar to the modern cultivars for grain yield. Moderate to high genetic variation was displayed by number of grains per spike, number of spikes per plant, 1000-grain weight, and harvest index. The heritability estimates ranged from 59% for grain yield to 99% for days to anthesis. Expected genetic advance (as % of the mean) was ≈34% for number of spikes per plant, number of grains per spike, and 1000-grain weight. Days to heading and to anthesis correlated positively with number of spikes per plant, shoot biomass, and straw biomass but negatively with number of grains per spike and harvest index. The strong direct effect of number of spikes per plant on grain yield was completely counterbalanced by its indirect negative effects via number of grains per spike and 1000-grain weight. Number of grains per spike and 1000-grain weight were positively correlated with grain yield, and they had large direct effects. These two characters, however, were negatively correlated and exhibited a substantial counterbalance effect via one another and via number of spikes per plant. The landraces could be improved by intercrossing the promising genotypes identified in this study, with simultaneous selection for earliness, fewer number of spikes per plant, greater number of grains per spike and heavier grains. For further improvement, crossing programs between the landraces and introduced germplasm may be necessary. This revised version was published online in July 2006 with corrections to the Cover Date.     

Resistance to bacterial blight (Pseudomonas syringae pv. pisi) in Spanish pea (Pisum sativum) landraces

Pea bacterial blight (Pseudomonas syringae pv. pisi) has long been known to be present in pea growing areas of Spain and to cause serious crop losses, although there is no published record of its occurrence. A collection of 16 isolates from a winter pea trial in Valladolid in 1991 which were shown in this study to be P.s. pv. pisi races 4 and 6 would appear to be the first published record of the disease in Spain. This occurrence of races 4 and 6 is the same as reported for winter-sown peas in the South of France. Ten Pisum sativum landraces from different geographical areas of Spain and considered to be representative of the traditional pea crop, were tested for resistance to seven races of P.s. pv. pisi. Seedlings of each landrace were stem inoculated with the type strain of each race in a glasshouse. Resistance exhibited by the different landraces mainly conformed to those previously described in pea cultivars indicating various combinations of the main resistance genes: R3, R2+4, R3+4 and R2+3+4. R3 was the most frequent R gene, being present in all landraces. R4 was present in four and R2 in three of the landraces tested. Variation for resistance within landraces was limited except for landrace accessions ZP-0102, ZP-0109 and ZP-0137 which also showed variation for morphological traits. The resistance responses of landrace ZP-0109 were difficult to interpret, but suggested a genetic mixture with some evidence of less well documented R genes, R5 and/or R6, and possibly some unknown resistance to race 6. This revised version was published online in July 2006 with corrections to the Cover Date.     

Variation between and within Ethiopian barley landraces

Up to 100 single plant derived lines of 18 barley landraces, collected from 18 localities of six barley growing regions of Ethiopia were studied for two years at Holetta, Ethiopia for variation in five quantitative traits; scald severity, earliness, plant height, 1000 grain weight, and leafiness. The relative latent period in the adult plant stage to barley leaf rust, a good measure for partial resistance, was assessed on the landrace lines at Wageningen, The Netherlands. The observed variation between and within landraces was very large for all traits. The magnitude of variation was so large that most, if not all, plants within a landrace had a different genotype. The landraces also varied in the degree of variation. Some landraces, 1726 and 3288 for instance, were more variable for most or all traits than other landraces such as 208925 and 212938. Days to heading and scald severity were significantly (P = 0.01) correlated with altitude, r being 0.66 and - 0.65, respectively. Resistance to scald and leafiness also increased with altitude. On average landraces became later, more resistant to scald and more leafy the higher the altitude of collection. This associated complex of traits could be an adaptation to the wetter and cooler conditions at higher altitudes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Water use efficiency among dry bean landraces and cultivars in drought-stressed and non-stressed environments

The agricultural use of water is higher than 85% in the western USA, resulting in an increasing water deficit in the region; this situation is commonly encountered throughout the world where irrigated and irrigation-assisted production systems are operational. The objective of this study was to examine differences among dry bean (Phaseolus vulgaris L.) landraces and cultivars in terms of water use efficiency (WUE), subsequently identifying those with a high water use efficiency. Six medium-seeded (25–40 g 100 seed wt⁻¹) landraces and cultivars of pinto and red market classes were evaluated in intermittent drought-stressed (DS) and non-stressed (NS) environments at Kimberly, Idaho, USA in 2003 and 2004. Each market class comprised one each of a landrace and old and new cultivars. Mean evapotranspiration (ET) in the NS environment was 384 mm in 2003 and 432 mm in 2004; the respective ET values in the DS environment were 309 and 268 mm. Mean seed yield was higher in the DS (2678 kg ha⁻¹) and NS (3779 kg ha⁻¹) environments in 2004 than in 2003 (688 and 1800 kg ha⁻¹, respectively). Under severe drought stress in 2003, WUE in the pinto bean ranged from 1.5 for the Common Pinto landrace to 4.4 kg ha⁻¹ mm⁻¹ water for cv. Othello. The Common Red Mexican landrace had the highest WUE (3.7), followed by cvs. NW 63 (2.8) and UI 259 (1.4) in the red market class. Under favorable milder climatic conditions in 2004, the mean WUE value was 10 kg ha⁻¹ mm⁻¹ water in the DS environment and 8.7 kg ha⁻¹ mm⁻¹ water in the NS environment. We conclude that dry bean landraces and cultivars with high WUE should be used to reduce dependence on irrigation water and to develop drought-resistant cultivars to maximize yield and WUE.     

The cultivation revival of a landrace: pedigree and analytical breeding

This paper aims at improving the legume landrace Fava Santorinis (Lathyrus sp.) through the study of the existing variability, and an intra-landrace pedigree, combined with analytical selection, scheme. The experiments were conducted at the farm of Aristotle University of Thessaloniki during five growing seasons (2005–2009), and the selection was applied on a spaced plant conditions. In the first stage, single-plant frequency distributions of the source landrace for grain yield and pod number plant⁻¹ was studied, and a percentage of 60.80% of non productive plants was found. In the second stage, improvement of grain yield relied on direct pedigree selection, accomplished by analytical selection for the number of pods plant⁻¹, plant leaf color and vigor. This procedure was followed along the first generation progenies, and, later on, along two successive generations on the offsprings of two populations, one with purple and the other with white flower color. In the third stage, the evaluation of the fourth-generation progenies of each population for grain yield, showed superiority ranging from 42.48 to 107.89% compared to the source landrace. Furthermore, the breeding procedure succeeded in: (i) decreasing the coefficient of variability of grain yield and pods plant⁻¹, thus increasing the stability of performance, (ii) reducing by 56.41 and 39.67% the non productive plants for white and purple flower populations, respectively, and (iii) maintaining the mean and the variability for pod traits as in the original landrace. Realized heritability for grain yield was positive during all selection cycle.     

Characterizing the molecular and morphophysiological diversity of Italian red clover

Red clover (Trifolium pratense L.) is the third major forage species in Europe, but there is limited information on the biodiversity and the genetic structure of landraces and natural populations which evolved in this region. The objective of this study was producing such information for Italian germplasm on the ground of molecular and morphophysiological diversity. The study included 16 Italian natural populations from a wide range of environments, four landraces representing the four traditional commercial ecotypes, and two varieties. Eight morphophysiological traits were assessed in a replicated trial under field conditions, whereas two AFLPs primer combinations with 140 polymorphic markers were recorded on a random sample of 13 genotypes per population. Ordination and classification results based on morphophysiological data clearly kept track of the type of germplasm (i.e. landrace or natural population) and its geographic origin, unlike results based on molecular markers. Euclidean distances among populations based on morphophysiological traits were not correlated with Nei’s genetic distances based on molecular markers according to Mantel’s test. Geographical distances among landrace or natural population material was correlated with distances based on morphophysiological traits but not with those based on molecular markers. The average within-population variation estimated via molecular markers was about 2.6-fold higher than that among populations, preventing an acceptable discrimination among most populations. On average, natural populations tended to have within-population variation similar to varieties and somewhat lower than landraces. Our results have implications for collection, conservation, exploitation and registration in a sui generis system of red clover genetic resources.     

Effects of N fertilization on yield for low-input production in Spanish wheat landraces (Triticum turgidum L. and Triticum monococcum L.)

A core subset of Spanish durum wheat landraces was evaluated at two nitrogen levels (80 and 220 kg/ha) to identify landrace genotypes adapted to low N production. Yield differences were statistically significant between N levels and among genotypes at both levels. Fifty-one per cent of the landraces yielded significantly more at low than at high N (low-N varieties) while 26% had a positive (high-N varieties) and 23% an indifferent (indifferent-N varieties) response to N fertilizer. No significant agromorphological differences were found among low and high-N varieties at low N level that conferred some advantage to low-N varieties. In contrast, high-N varieties possessed longer grain-filling period under high N level. Phenological characters showed an important influence on yield and on the performance of the varieties within each subgroup. The traits affecting grain yield most positively, mainly the low-N varieties, were long filling period and earliness. Five entries were selected for prebreeding to low N adaptation.     

Farmers' seed management practices open up new base populations for pearl millet breeding in a semi-arid zone of India

Farmers in western Rajasthan (north‐west India) produce and maintain their landrace populations of pearl millet through their own distinct seed management practices. The objective of this study was to characterize morphological and agronomic variability of different traits between and within three farmers' populations using quantitative‐genetic parameters. Populations examined were a typical landrace and two modified landraces, which were generated through farmer introgression of modern varieties with different levels of subsequent selection. From these three populations, 100 random full‐sib progenies were evaluated in field trials at two locations in western Rajasthan over two years. Significant genetic variation existed within the three populations. Estimates of heritability were moderate to high for all observed traits. Predicted selection response for grain yield across environments was 1.6% for the typical landrace and 2.2% for both the modified landraces. Results suggest that the introgression of modern varieties into landraces had increased the genetic diversity. Therefore, farmers' current breeding activities could open up new resources for plant breeding programmes aiming at plant improvement for the semiarid zones of India.     

Variation for resistance to Puccinia hordei in Ethiopian barley landraces

Summary Up to 100 single plant derived lines of 18 Ethiopian barley landraces were evaluated for infection type in the seedling and adult plant stage, and for latent period in the adult plant stage only. A low infection type indicates the presence of race-specific resistance genes of the hypersensitive type, while the latent period is the major component of the polygenic, partial resistance.In the seedling stage 1721 of these single plant derived landrace lines were assessed for infection type against two barley leaf rust races. In the adult plant stage 1227 from these 1721 lines were evaluated for infection type against one race. In the seedling stage 2 (against race 1-2-1) and 29 against race A) out of the 1721 lines showed an infection type lower than 6–7 on the 0 to 9 scale. In the adult plant stage none of the 1227 lines had an infection type lower than 6–7 against race 1-2-1.The variation between and within the landraces for latent period in the adult plant stage was large. Some landraces such as landrace 212845 showed a highly significant and longer mean latent period than most other landraces. Virtually all plants in all landraces carry at least some partial resistance.The near-absence of race-specific, major, resistance genes and the high frequency of moderate levels of partial resistance indicates that the durability of leaf rust resistance in Ethiopian barley landraces is due to the latter type of resistance, and that the multiline principle does not operate.     

The introduction of the common bean (Phaseolus vulgaris L.) into Western Europe and the phenotypic variation of dry beans collected in The Netherlands in 1946

The first introduction of common bean from Central/South America into Western Europe most likely took place around 1500. The attractive bean seeds and their easy transportation warranted numerous additional introductions, not only from the Americas, but also from other areas where the common bean had been introduced. Bean seeds also must have been transported all over Europe both locally and internationally. Natural and human selection took place in and among introductions as well as in hybrid populations. Strong human selection may have led to pure garden forms which often occur in The Netherlands. In the period 1945–1948 a dry-bean collection of some 1500 accessions was made in The Netherlands. These have been classified into various criteria: 1. landraces, ‘primitive’ garden forms and cultivars, 2. (semi)climbing or bush types, 3. various seed colour types, including whitish, brownish, yellowish, black and variegated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Agronomic diversity of naked barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.): a potential resource for breeding new food barley for Europe

Naked (hulless) barley was neglected by plant breeders in Europe during the period of intensive crop improvement in the 20th Century, but it is now receiving renewed interest due to the potential health benefits it can convey. Very few naked barley cultivars have been developed for modern UK or European agricultural systems, in contrast to the wide diversity of naked barley in Asia. Prior to initiating any breeding programme, phenotyping in UK field conditions is needed to assess the value of existing exotic landraces. This article reports such a programme where naked barley landrace lines were grown alongside modern cultivars and unimproved UK hulled landrace lines over 4 years at a research station in North Wales and assessed for yield and agronomic traits. Multivariate analysis of the traits suggested that accessions clustered by region of origin. Himalayan landrace lines formed Eastern and Western clusters while Japanese and Korean landrace lines were distinct from these. European naked barleys were found to be closest to European hulled barleys, suggesting that the distinctiveness of the Asian naked barley landrace lines was due to origin rather than the naked grain trait per se. The only agronomic trait that could be attributed to naked grain was poorer crop establishment, but some Himalayan landrace lines showed vigorous seedling growth. Modern lines of naked barley from Syria gave superior yields to old UK hulled barleys, indicating that there is potential for breeding modern UK cultivars of naked barley.     

Variation within improved cultivars and landraces of lucerne in Central Italy

Summary A variety must be distinguishable, uniform, stable and of sufficient productivity to be officially registered. In Italy landraces of lucerne are still widely used because they are characterized by a good persistence and productivity in their area of origin and adaptation.The landrace from Casalina (20 km south of Perugia, Central Italy) has higher dry matter production than many other commercial cultivars. The objective of this paper was to measure the variation of the landrace Casalina and compare it with that of the commonest cultivars available on the market and with some lines selected from the landrace Casalina.The experiment consisted of 11 entries: Casalina, two selections from Casalina (one for high seed yield and one for frequent cuttings), the registered landrace Italia Centrale and 7 registered cultivars. Each entry was represented by 80 genotypes transplanted in the field 60×40 cm apart in a randomized block design with 4 replications. In 1991 the following characters were recorded on a single plant basis: time of first flowering, height, number of shoots and dry matter yield at the first harvest, time of second flowering, leafiness, height, number of shoots and dry matter yield at the second harvest, height, number of shoots and dry matter yield at the third and fourth harvest. Height, number of shoots and dry matter yield at the first harvest, dry matter at the second and third harvest were recorded during the 1992 season.Casalina was as variable as the other entries in 77% of the comparisons; it was more variable in 8% of the comparisons and less variable in 15% of the comparisons. In conclusion, the variation of landrace Casalina is equal to or less than that of registered varieties so that it could be directly registered at the National Registry of Varieties.     

Genotypic and bio-agronomical characterization of an early Sicilian landrace of globe artichoke

In Sicily, the increasing use of exotic globe artichoke germplasm is eroding the presence of autochthonous landraces, including the long established ‘Violetto di Sicilia’. Ten clones have emerged from a clonal selection programme in this landrace, and here we describe the variation that they capture both at the level of AFLP-based genotype and phenotypically with respect to key productivity traits, on the basis of two seasons of field evaluation. The clonal selections yielded, on average, 8.9 heads per plant (equivalent to a fresh weight yield of 1.28 kg). Two clones yielded particularly well in both growing seasons (10.6 heads, equivalent to 1.46 kg per plant), while another pair produced particularly large heads (on average 165 g) and a high receptacle incidence (on average 19.3 g 100 g⁻¹ fresh weight). Both the number of days to first harvest and the quantity of head dry matter were subject to a significant degree of ‘clone × year’ interaction. Yield, the number of heads per plant and receptacle incidence were associated with a moderate (0.30–0.53) broad sense heritability, indicating that these traits could be successfully improved by phenotype-based clonal selection. AFLP fingerprinting was able to discriminate between all the clones, based on only three primer combinations. A principal component analysis based on the AFLP fingerprints was used to compare the selected clones with a set of individuals chosen on the basis of maximum genetic diversity. This comparison suggested that the new clone set was representative of the genetic variation present in ‘Violetto di Sicilia’, because the diversity captured by the two sets was largely overlapping, confirming the possibility of carrying out clonal selection in this globe artichoke landrace without compromising its preservation in situ.     

Participatory crop improvement and formal release of <Emphasis Type="Italic">Jethobudho</Emphasis> rice landrace in Nepal

Jethobudho is an aromatic rice landrace of the Pokhara valley in middle hills of Nepal. Although local consumers are willing to pay a high price for its purchase, the landrace has a problem with quality variation. Decentralized participatory population improvement for specific market-identified traits was conducted on “Jethobudho” populations collected from farmers’ fields in seven geographic regions of the valley in Nepal. The preferred post harvest quality traits, field tolerance to blast and lodging, and superior post harvest quality traits of Jethobudho were established by a consumer market survey. These traits were used for screening the materials. 338 sub-populations of Jethobudho were evaluated for yield, disease, lodging resistance, and post harvest quality traits. Significant variation was found for culm strength, neck blast tolerance, awn characteristics, panicle length, number of grains per panicle, test grain weight and post harvest quality traits, whereas no significant variation was found in grain yield, plant height, tiller number, maturity period and leaf blast. Based on these identified traits and micro-milling evaluations, 183 populations were screened in on-farm and on-station nurseries, and in succeeding years populations were further screened by plant breeders and expert farmers in research trials, resulting in the selection of 46 populations for post harvest quality traits. Six accessions with similar agronomic traits, field tolerance to blast and lodging, and superior post harvest quality traits, were bulked and evaluated on-farm using participatory variety selection (PVS). The enhanced Jethobudho accessions were also evaluated for aroma using simple sequence repeat (SSR) and found to have unique aromatic genetic constitution. Community based seed production groups were formed, linked to the Nepal District Self Seed Sufficiency Programme (DISSPRO), and trained to produce basic seeds (truthfully labeled) of Jethobudho. The National Seed Board of Nepal released the enhanced landrace in the name of “Pokhareli Jethobudho” in 2006, as the first bulk variety of traditional high quality aromatic rice improved through participatory plant breeding to be formally released in Nepal for general cultivation under the national seed certification scheme. Landrace improvement is shown as an important option for supporting programmes for in situ conservation of landraces on-farm.     

Nutritional and physicochemical variation in Turkish kabuli chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.) landraces

We examined the physical, physicochemical, and cooking properties of 91 kabuli chickpea landraces from Turkey, using two cultivars (İnci and İzmir-92) as controls. All landraces were grown under the same agroclimatic conditions to eliminate variance caused by genotype × environment interactions. There was high diversity among the landraces in the contents of protein (17.55–23.31%), fat (4.45–6.11%), ash (2.54–3.41%), fiber (2.03–4.18%), starch (41.76–49.07%), moisture (6.39–10.57%), 100-seed weight (25.03–51.67 g), hydration capacity (0.2585–0.6169 g/ml), swelling index (0.7207–1.1859), swelling capacity (0.15–0.32 ml seed⁻¹), cooking time (33–72 min), and seed density (0.8450–1.4800 g/ml). Regional analysis of landraces showed significant differences with respect to nutritional characteristics and cooking parameters. There were also significant relationships between various seed quality and cooking parameters. Together, our results provide an initial step toward identification of chickpea landraces that may be useful for development of high-quality chickpea cultivars.     

Spanish barley landraces outperform modern cultivars at low‐productivity sites

Barley landraces from the western Mediterranean area have not been thoroughly exploited by modern breeding. This study aims at assessing the agronomic value of a core collection of lines derived from landraces of Spanish origin and to compare them with sets of successful old and modern cultivars. The agronomic performance of a set of 175 barley genotypes, comprising 159 landrace‐derived lines and 26 cultivars, was evaluated in a series of 10 field trials, carried out over 3 years and several locations. The most relevant trait of the landraces was higher grain yield at low production sites than cultivars, which may be related with better ability to fill the grain under stressful conditions. On the other hand, lateness, excessive plant height and lodging were negative traits frequently found in the landraces. Large genotype‐by‐environment interaction (GEI) for grain yield was detected, related partly with differences between germplasm groups, probably indicating local adaptation. GEI was also associated with the interaction of heading time and powdery mildew resistance with temperature.     

Durum wheat landraces from Syria

Syrian durum wheat landraces from diverse collection sites were evaluated for agronomic performance under arid conditions over two seasons at four locations, at two levels of nutrient availability.Grain yield differed considerably among locations. Within locations, significant population and fertilizer effects were demonstrated. In most cases, maximum yield was achieved by landraces, which demonstrates the breeding value of local germplasm. In a particular environment, the population effect was nonsignificant for total dry matter production, but significant for straw and grain yield. Nitrogen application was ineffective if moisture availability was the dominant growth limiting factor.Correlations between plant characteristics at evaluation and collection site characteristics were limited, and therefore, their utilization in germplasm evaluation appear limited. The negative relation between grain yield and soil nitrogen content at the collection site may be caused by the comparative disadvantage that germplasm from regions with favourable growing conditions has under low-yielding conditions.Particular environmental conditions at the collection site were no indicator for the response to changed growing conditions. Relatively high grain yields under good and adverse growing conditions excluded each other in all but two cases. Also, it was difficult to relate grain yield to regions of collection, as the response of individual landraces from a certain region to changing growing conditions differed strongly. Differentiation on the basis of landrace groups appears more promising. The Hauran landrace group provided the largest number of populations with relatively high grain yields over diverse environments.     

Random amplified polymorphic DNA (RAPD) markers variability among cultivars and landraces of common beans (Phaseolus vulgaris L.) of south-Brazil

To evaluate the variability among cultivars and landraces of common bean(Phaseolus vulgaris L.), 15 cultivars and 18 landraces of common bean (Phaseolus vulgarisL.), a undefined species of Phaseolus,two landraces of Vigna angularis L., and a landrace of soybean (Glycine maxL.), were screened with fifteen oligonucleotide primers in PCR reactions. An average of 20.3 RAPD bands were scored per primer. A total of 304 amplification products were scored of which 88.8% were polymorphic among Phaseolus genotypes. Based on the RAPD markers, four major clusters were formed. Three clusters corresponded to the soybean, to the two Vigna angularis landraces, and to the Phaseolus sp. landrace, respectively. The fourth cluster include all the landraces and cultivars of Phaseolus vulgaris. This large group could be separated into three subgroups that were correlated with the phaseolin patterns and the average seed weight of the genotypes. The analysis shows that most of the landraces collected in South Brazil (17 out of 18) belong to the Andean gene pool, and most of the cultivars (13 out of 15) belong to the Middle American gene pool. This revised version was published online in July 2006 with corrections to the Cover Date.