Quantitave evaluation of Ethiopian landraces of lentil (Lens culinaris)

Summary One hundred and fifty-six landrace populations of lentil (Lens culinaris Medikus) collected from 10 provinces in Ethiopia were evaluated for a set of six quantitative traits at three sites contrasting in altitude. Consistent regional differences among landraces were found for time to flower and maturity, 100-seed weight, number of seeds/pod and plant height. The regional differences were clarified by a discriminant analysis based on 100-seed weight, time to flower and plant height. The lentil of the West Highlands was early and short, that of the North Highlands was large-seeded, whereas lentils from the Central Highlands were the least distinctive group. Selection for seed size was the result of local human preferences. Humans were probably also responsible for the lack of adaptive value of plant phenology in relation to altitude. Selection for seed yield at the low and middle elevation sites gave a positive response to selection at both sites. However, selection for yield at the highland site did not give a positive response elsewhere, indicating that adaptation to highland conditions differed from that at lower elevations.     

The evolution of lentil (Lens culinaris Medik.) cultivation in Italy and its effects on the survival of autochthonous populations

At the beginning of the 20th Century Italy was one of the most important producers of lentil in the Mediterranean basin. Presently, this pulse is mainly cultivated in marginal areas of Central and Southern Italy and in some small islands. As a result of the reduced attention devoted to lentil, several autochthonous populations have disappeared together with the traditions related to their cultivation. Moreover, how long the cultivation of those still grown today will continue is unpredictable. Governmental and local associations have a time window for anticipating a possible epoch when to grow these landraces will be no longer profitable. In the last decades the Germplasm Institute of the National Research Council (Bari, Italy) and the Institut für Pflanzengenetik und Kulturpflanzenforschung (Gatersleben, Germany) have collected 63 lentil populations in Italy, presently stored ex situ. The evaluation of this collection has shown the existence of an appreciable morphological, agronomic and genetic diversity that could foster future breeding programmes. It is concluded that there is an urgent need to promote the survival of lentil populations in situ, since this will further support the adaptation and evolution of autochthonous genotypes in their original environments.     

The major Italian landraces of lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> Medik.): Their molecular diversity and possible origin

The eleven most known landraces from central and southern Italy were analysed using ISSR markers on 15 randomly chosen individuals for each landrace, with the aim of assessing genetic variation within and among landraces and possibly ascertaining their origin and genetic relationships. A total of 164 loci were observed, 128 of which (78.05%) were polymorphic. Gene diversity over all landraces was I = 0.3759. The highest within-landrace diversity was observed in samples from the Apennine ridge and for one Sicilian landrace; on the other hand, samples from the small Sicily islands were less variable. Principal Component Analysis and AMOVA allowed the discrimination of groups of landraces with higher similarity. Analyses indicate that the small Sicily islands landraces are very closely related to one another and seem to be derived from the peninsular material; moreover, they help disclose relationships among geographically close landraces. The knowledge so acquired can, therefore, contribute to elaborate strategies for increasing the economical value of élite landraces and to protect producers from frauds.     

Diversity, distribution and management of yam landraces (Dioscorea spp.) in Southern Ethiopia

Yam (Dioscorea spp.) is widely grown in many parts of Ethiopia and plays a vital role in local subsistence. Nevertheless, its diversity has not been studied in detail. A survey covering 339 farm households and eight districts was conducted in the major yam growing regions of Southern Ethiopia to investigate the diversity and distribution of yam landraces using structured and semi-structured questionnaires. A total of 37 named landraces were recorded, with a range from one to six (mean 2.9) on individual farms. Farmers’ decisions regarding the number and type of landraces maintained was influenced by tolerance of the landraces to drought, their maturity time and market demand. Most landraces had limited abundance and distribution, and only a few dominant landraces were widely grown. There was also variation amongst districts with respect to diversity, distribution and abundance of the landraces found. In the majority of the localities surveyed, farmers reported a decreasing trend in the number of landraces maintained on individual farms and in the overall yam production. Besides, in those limited areas where yam production is expanding, farmers are increasingly relying on a few selected landraces that mature early. Findings of this study suggest that local farmers in Wolayita and Gamo-Gofa zones maintain considerable yam diversity that remains to be further explored for sustainable utilization and conservation of the available genetic resources.     

Evaluation of genetic diversity of bread wheat landraces from Pakistan by AFLP and implications for a future collection strategy

We used amplified-fragment-length polymorphism (AFLP) markers to evaluate genetic variation in a set of bread wheat (Triticum aestivum L.) landraces and improved materials. Landraces collected from different geographic and agro-ecological zones in Pakistan in 1987, 1989 and 1991 were separated into two groups based on their geographic origins: northern (Himalaya) and south-western (Balochistan) Pakistan. Six AFLP primer combinations detected 453 AFLP markers in the 43 landrace accessions and four high-yield varieties (HYVs). Of these, 225 (49.67%) were rare (shared with < 5% of all accessions). Among these rare alleles, 23 (10.22%) were common in the Himalaya (shared with > 10% of accessions collected there) but were not found in Balochistan. We conclude that there is a higher probability of collecting rare alleles at overall, but which are in contrast locally common ones in the Himalayan region. Gene diversity was 0.17 in the Himalayan group and 0.15 in the Balochistan group. Considerable genetic variability was found in both groups. Accessions from different agro-ecological zones were indistinguishable by cluster analysis, indicating intensive seed trading within the country. Cluster analysis indicated that the landraces and the HYVs are genetically distinct; suggesting that genetic erosion of wheat landraces has been unlikely taken in place. This study provides an example of how analysis of existing materials and data, can serve as a basis for future collection planning and conservation policies.     

Development of Core Collection in Pigeonpea [<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millspaugh] using Geographic and Qualitative Morphological Descriptors

Pigeonpea is an important pulse crop grown by smallholder farmers in the semi-arid tropics. Most of the pigeonpea cultivars grown to date are selections from the landraces, with a narrow genetic base. With the expansion of the crop to newer areas, problems of local importance are to be addressed. Hence, an economically feasible and faster germplasm evaluation mechanism, such as a core collection, is required. This article describes the development of core collection from 12,153 pigeonpea accessions collected from 56 countries and maintained at ICRISAT, Patancheru, India. The germplasm accessions from 56 countries were placed under 14 clusters based primarily on geographic origin. Data on 14 qualitative morphological traits were used for cluster formation by Ward’s method. From each cluster ≈10% accessions were randomly selected to constitute a core collection comprising 1290 accessions. Mean comparisons using Newman–Keuls test, variances’ comparisons by Levene’s test, and comparison of frequency distribution by χ²-test indicated that the core collection was similar to that of the entire collection for various traits and the genetic variability available in the entire collection is preserved in the core collection. The Shannon–Weaver diversity index for different traits was also similar for both entire and core collection. All the important phenotypic associations between different traits available in the entire collection were preserved in the core collection. The core collection constituted in the present study facilitates identification of useful traits economically and expeditiously for use in pigeonpea improvement.     

Genetic relationships and diversity among Brazilian cultivars and landraces of common beans (Phaseolus vulgaris L.) revealed by AFLP markers

The genetic variation and relationships among 31 accessions of Phaseolus vulgaris L., and two representatives of Vigna unguiculata L., were evaluated by AFLP analysis. A total of 263 DNA fragments across all materials were scored using nine primer combinations, averaging 32 per primer. More than 95% of the amplification products showed polymorphism, indicating high variation at the DNA level among these accessions. Pair-wise genetic similarity (Jaccard's coefficient) ranged from 0.553 to 0.840, with a mean of 0.765. Twenty-three accessions (70%) clustered into three groups. A majority of the commercial cultivars (91%) clustered within a single group, whereas the landraces were distributed along all the variation. An apparent correlation with phaseolin types was detected. Results of this study suggest that Brazilian landraces truly represent the overall genetic variability of Phaseolus vulgaris, confirming the multiple origins of these materials, and their potential as a source of variation for breeding programs.     

Analysis of morphological variation in wild beet (Beta vulgaris L.) from Sicily

Summary In this paper the variation pattern of the Sicilian Beta germplasm collection is analysed. Accessions from Sicily were grown under controlled conditions and were evaluated morphometrically. Geographical distribution patterns of morphological characters are identified and the putative classification of the collection into coastal and inland populations is reassessed. Between adjacent populations significant variation was found for Petiole length, Leaf length, Leaf width and Biomass, however no one variable unambiguously reflected a geographical pattern. Overall differences between coastal and inland populations were small. Petiole length and rate of generative development were found to be important for distinguishing between these groups. Interferences are drawn on how the collection from Sicily could be rationalized to avoid excessive duplication.     

Study of a germplasm collection of loquat (Eriobotrya japonica Lindl.) by multivariate analysis

Loquat species (Eriobotrya japonica Lindl.) originated in China, later was introduced in Japan. However, introduction in Europe occurred much later, in 18th century, it was introduced as an ornamental tree. Since then, the species was very well adapted to the Mediterranean climate, mainly in South East of Spain, where is located more than 50% of total European crop production. A European Project titled ‘Conservation, evaluation and collection of underutilized fruit species’ supported surveys and collection of plant material from these species in the Mediterranean basin countries. One of these surveys resulted in a germplasm collection of loquat established at IVIA, Valencia, Spain. This collection is being extended with new accessions collected across the world, currently the collection have 123 accessions under study. Germplasm management needs first a characterization of the plant material introduced and second diversity studies into the collection that could point out the variability pattern, to establish groups of accessions with similar traits and the most significant variables. These results allow organizing the information gathered for further uses. In this paper, 62 accessions from the IVIA germplasm collection were studied. Results from 43 variables were gathered and data studied by multivariate analysis. The analysis allowed summarizing the data tables with new variables containing most of the information. These results along with those obtained in the coming years will allow define a nuclear collection (minimum number of accessions that contained all the variability present in the collection).     

Evaluation of Wild Lens Taxa for Agro-Morphological Traits, Fungal Diseases and Moisture Stress in North Western Indian Hills

Exploitation of wild gene pool for breeding is a common practice in an increasing number of cultivated plants. The cultivated lentil could not attain the substantial improvement in the yield potential due to loss of genes for higher productivity and lack of resistance against biotic and abiotic stresses. The absence of evaluation data of wild lentils for characters of economic importance, besides biotic and abiotic stresses, is one of the constraints in their use in lentil breeding programme. In the present study, 70 wild accessions from four wild Lens subsp./sp. (L. culinaris subsp. orientalis, L. odomensis, L. ervoides and L. nigricans) along with 3 checks (Precoz, PL-406 and PL-639) were evaluated for phenological and agro-morphological characters, for their reaction to three fungal diseases (wilt, powdery mildew and rust) and screened for tolerance to moisture stress. The wild accessions showed higher performance for branches/plant as compared to cultivated genotypes. Similarly, a few accessions of L. culinaris subsp. orientalis were earlier to flower and had higher seeds and seed yield/plant as compared to cultivated lentil. However, some were comparable with cultivated genotypes for flowers/peduncle, peduncle length and plant height. The mean performance for flowers per peduncle, leaflets per leaf, plant height, seeds and seed yield per plant increased, while decreased for days to flowering and maturity, and branches per plant during the evolution of cultivated lentil from the wild Lens taxa. Of Lens taxa, L. nigricans had the maximum resistant accessions for biotic and tolerance to abiotic stresses. The valuable variation existing among wild accessions can be exploited following introgression with cultivated lentils. It will help in the flow of useful genes from wild to cultivated lentil for generating wide spectrum of variability and its subsequent use in genetic restructuring of lentil.     

Diversity analysis of Central Asia and Caucasian lentil (<Emphasis Type="Italic">Lens</Emphasis><Emphasis Type="Italic">culinaris</Emphasis> Medik.) germplasm using SSR fingerprinting

Diversity analysis was performed among 39 cultivated lentil (Lens culinaris Medik.) accessions of Central Asia and Caucasian origin using five highly polymorphic microsatellite markers. A total of 33 alleles determined ranging from 3 to 8 per locus. Estimated gene diversity value for 33 loci was 0.66. Genetic similarity indices among 39 accessions ranged from 0.24 to 1.0. Cluster analysis using the unweighted pair group method with arithmetic mean method classified accessions into six major groups at 0.5 similarity coefficient. More than half accessions from Tajikistan formed large cluster. On the other hand, a few accessions from each country showed unique genotypes. Overall, most of the accessions, except ones with closely related origin, were distinguished by the present high quality DNA fingerprinting. This molecular diversity information gives important basis for conservation strategy in gene bank and exotic germplasm introduction in breeding programs in Central Asia and Caucasian countries.     

Changes in the diversity and geographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghum bicolor (L.) Moench) varieties in Niger between 1976 and 2003

Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes, we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name and type of varieties according to important traits for farmers were considered at different spatial scales (country, region, village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’ seed systems.     

Phenotypic diversity and morphological characterization of Amygdalus L. species in Lebanon

In this paper, we report on morphological diversity of Amygdalus L. species native to Lebanon, following a countrywide survey of almond germplasm whereby a total of 149 accessions were collected throughout the country and characterized by thirteen quantitative and four qualitative traits. The results indicated that the genetic diversity of Amygdalus communis L., Amygdalus korshinskyi Hand.-Mazz., and Amygdalus orientalis Duh. in Lebanon is high. Principal component analysis revealed that nut weight, nut volume, nut width, kernel volume and shell strength had highest loading in the first component that accounted for 38.7% and 46.7% of total variation in A. communis and A. orientalis, respectively. In contrast, leaf traits were present in the second component which accounted for 18% and 23.2% of total variation in each species, respectively. No significant correlations were detected between leaf parameters and fruit traits in both species. The results indicated that quantitative leaf characters for all three species were determined by rainfall and not altitude whereby adjacent accessions located in drier areas had smaller leaf sizes than those located in more humid regions. Quantitative fruit characters did not seem to vary accordingly. Qualitative leaf traits in all three species reflected a variability which was independent of rainfall. A. communis populations showed high variability, suggesting that they could be a valuable source in almond improvement programs.     

Ploidic and Molecular Analysis of ‘Morado de Huetor’ Asparagus (Asparagus officinale L.) Population; A Spanish Tetraploid Landrace

A study has been conducted into the genetic variation analysis of the tetraploid asparagus landrace ‘Morado de Huetor’ and its relationship with current commercial cultivars using Random Amplified Polymorphic DNA (RAPD) molecular markers. The presence of different ploidic levels in the ‘Morado de Huetor’ landrace has been also studied using cytogenetic analysis. Ten decamer oligonucleotides were used to obtain RAPD markers and to characterise 52 individuals of ‘Morado de Huetor’, 7 of the tetraploid cultivar ‘Purple Passion’, and 55 of 5 diploid hybrid commercial cultivars. Jaccard similarity index was calculated and a cluster analysis using UPGMA (Unweighted Pair-Group Method using Arithmetic Average) was performed. Tetraploid asparagus, ‘Morado de Huetor’ and ‘Purple Passion’, were well differentiated from the diploid ones showing a higher genetic variability. This result suggests a different origin for tetraploid and diploid asparagus varieties. Within the diploid cultivars a variety distribution was obtained. A specific monomorphic band (OPB20₈₈₃) was found in tetraploid varieties. Within the diploid cultivars, two bands (OPB20₈₃₀, OPC15₇₀₅) can be used to distinguish between the hybrid cultivars used in this study. Tri-, penta-, hexa-, and octoploid plants were found in ‘Morado de Huetor’. The origin of these ploidic levels is discussed and their use in the development of new varieties is proposed. In conclusion, ‘Morado de Huetor’ is a genetic resource that could be used to increase the narrow genetic background reported in diploid asparagus cultivars.     

Genetic Relationships and Variation among Biotypes of Dallisgrass (Paspalum dilatatum Poir.) and Related Species Using Random Amplified Polymorphic DNA Markers

The genus Paspalum L. consists of more than 400 species. Around twenty-five informal groups of species are recognized in Paspalum and the Dilatata group is of special interest because its members are excellent potential forage grasses. Seventy-five germplasm accessions, representing 15 taxa, were analyzed using randomly amplified polymorphic DNA (RAPD). Polymorphisms were observed with twenty-two primers in the Dilatata group and 16 of those were analyzed. Four hundred and four different RAPD fragments were generated, resulting in an average of 25.2 bands per primer. Among the 404 markers analyzed, 48 (11.88%) were exclusive for the P. dilatatum Poir. biotypes, 31 (7.67%) were exclusive to taxa belonging to other groups included in this study, 28 markers (6.93%) were diagnosed for other species of the Dilatata group and 16 (3.96%), for natural hybrids. Extensive RAPD variation was found among the species studied. Inter- and intra-taxonomic polymorphisms were detected. A dendrogram based on the RAPD data shows some clusters corresponding to the same taxa. However, the biotypes of P. dilatatum do not form a cluster. The present work confirms that the RAPD technique can be used to determine genetic relationships between the taxa belonging to the Dilatata group.     

Characterization of a flint maize (Zea mays L. convar. mays) Italian landrace: I. Morpho-phenological and agronomic traits

Maize (Zea mays L.) landraces have the highest genetic variation and adaptation to the natural and anthropological environment where they have evolved. Surveying both qualitative and quantitative morphological traits of existing landraces may be useful in maintaining their genetic diversity and preserving them from genetic erosion. Our research deals with the morpho-phenological and agronomic characterization of a flint maize landrace, named 'Nostrano di Storo', still grown in an inland hilly environment in the low valley of Chiese River in Trentino, North-Eastern Italy. The majority of plants from twenty field populations proved to belong, with few exceptions (NSt2, NSt9, NSt11), to a single population. It means that the plant material long grown in this area and maintained by local farmers through yearly selection forms a single landrace within which some populations (i.e. NSt1, NSt3, NSt4, NSt7, NSt10, NSt18, NSt19, NSt20) could be considered as most representative and taken as 'core'. This is supported by the fact that the genetic variability was much higher within than between field populations: half of the plant and ear traits investigated did not show any significant difference between populations whereas all traits but two showed highly significant differences within populations. Selection carried out over the years by each farmer according to his own criteria produced little genetic differentiation within the original population. Gene flow among farmer populations, most likely occurred through both pollen dispersion to neighboring cultivated fields and seed exchange among farmers, may help to explain the low genetic differentiation. This information is useful for both planning conservation and recognizing the landrace as a unique germplasm source of specific geographic origin.