Shannon-Weaver Diversity Index Research Articles

Study of the phenotypic variation of some accessions of beans (vicia faba.l) in the wilaya of Tlemcen

The aim of this study was the morphometric characterization of 8 bean accessions (vicia faba L) in different localities in the wilaya of Tlemcen, we studied 8 agromorphological characters, were the objects of a statistical study by the software R. Phenotypic diversity was determined by the Shannon-Weaver diversity index (H ') at different levels. The estimated H showed high phenotypic variability for different traits with an average H of 0.63. The results of the Multiple Correspondence Analysis (PCA) and the Hierarchical Classification (CAH) showed a clear distinction between the accessions.

Quantitative Analysis, Distribution and Traditional Management of Pigeon Pea [Cajanus Cajan (L.) Millsp.] Landraces’ Diversity in Southern Benin

Pigeon pea (Cajanus cajan (L.) Millsp.) is an important drought tolerant legume cultivated in the semi-arid regions, mainly in Sub-Saharan Africa. Despites its important potential, the crop is neglected and underutilized in many countries including Benin. In order to develop efficient in-situ strategies conservation, a study was conducted to quantify pigeon pea landrace diversity and access its spatial distribution and traditional management by local communities in southern Benin. Therefore, an ethnobotanical survey was conducted in 20 producing villages in southern Benin. Altogether, 26 farmernamed landraces further grouped into five categories were recorded with the number of landraces really cultivated per farmer comparably lower than that listed. Besides, two landraces’ categories were found to be common in the study area while two other were found highly threatened. Diverse parameters such as varietal richness, Shannon-Weaver Diversity Index, Simpson index and Pielou’s evenness were used to quantify pigeon pea diversity that appeared to be unequally distributed through the different agro-ecologies and villages surveyed. The study confirmed the absence of correlations between farmers’ gender and landrace diversity which was nonetheless found to be significantly shaped by the ethnic group and the field size exploited by farmers (P < 0.05). In diversity management, five preference criteria with variable importance across the ethnic groups were used by farmers of which cooking time and market value appeared to be the most important. Exhaustive germplasm collections, morphological/molecular characterizations of these landraces are required for efficient conservation of this important but neglected crop genetic resource in Benin.

Evaluation of two different methods to measure the effects of the management regime on the olive-canopy arthropod community

The effects of the management regime, mostly differentiated for using or not insecticides, on biodiversity have frequently been difficult to analyze and understand because of the rapid re-colonization by good-dispersers, the quick recuperation of generalists and the continuity of insecticide-resistant arthropod species. The presence of these different communities may produce values of abundance, diversity indices and species richness which do not reflect the changes caused by the impact of the insecticides in the sprayed area. In this study we assess the impact of the olive tree management on the arthropod community and the changes in this community according to the blooming season. This study has been developed in olive groves subjected to conventional and organic management regimes by two different approaches: (a) the abundance-diversity approach, measuring and comparing abundance, richness and the Shannon-Weaver diversity index (H’) of total arthropods and per guild and (b) the food-web approach, building food-webs and comparing their unweighted quantitative descriptors. We sampled the arthropods in the tree canopy in six conventional and six organic olive groves (12 plots), and in two of the periods of greatest diversity and abundance: pre-blooming and post-blooming seasons. The abundance of total arthropods, but only those within the guild of phytophagous, diminished significantly when insecticides were used. The species richness of total arthropods and specifically predators were also reduced in the conventional plots. These variables were always greater in organic olive groves. Conversely, the total and per guild Shannon-Weaver diversity index (H’) did not detect any management effect on the olive-canopy arthropod community. Furthermore, all the food-web unweighted quantitative descriptors such as size, complexity and prey-predator asymmetries showed the significant effect of the management on the olive-canopy arthropod community and also presented greater values in organic olive groves. We also found that the blooming season did not significantly change the food-web structure, contrary to what we predicted. However, predator, parasitoid and phytophagous abundance, total and predator richness were greater in the post-blooming season. This study shows that the abundance-diversity approach, and especially H’ diversity index, was not useful for describing the effect of different management systems on the canopy arthropod community. On the contrary, the food-web approach emerges as a useful tool for understanding and evaluating the ecological effect of the application of insecticides (and probably other disturbances during the management) affecting the agro-ecosystems.

Genetic differentiation among selected tepary bean collections revealed by morphological traits and simple sequence repeat markers

ABSTRACTUnderstanding the genetic relationship of crop ideotypes is essential for genetic analysis and breeding. The objective of this study was to determine genetic differentiation present among 20 selected tepary bean (Phaseolus acutifolius A. Gray) genotypes using morphological traits and simple sequence repeat (SSR) markers in order to identify genetically unique parental lines to develop breeding populations. Phenotypic diversity was estimated using Shannon-Weaver diversity index (H’), principal component analysis (PCA) and cluster analysis (CA). Genotypic diversity was estimated using Jaccard's genetic distances and CA. Shannon-Weaver diversity index values for the studied morphological traits ranged from 0.89 to 0.99, with a mean of 0.95 revealing high phenotypic differences among test genotypes. PCA identified four useful principal components (PC's) which contributed to 73% of the total phenotypic variation of collections. PC1 accounted for 28% of the total variation correlated to dry shoot mass and number of pods per plant. PC2 correlated with number of seeds per pod, grain yield and harvest index and contributed to 21% of total variation. The mean observed (Ho) and expected (He) heterozygosity values were 0.45 and 0.51, respectively revealing moderate genetic differentiation among genotypes. The mean polymorphic information content was 0.52, suggesting efficient discriminatory power of the SSR loci useful in future tepary bean genetic diversity analysis. The current study revealed moderate genetic differentiation among the studied tepary bean genotypes. Morphological traits and SSR markers well-correlated in allocating the tepary bean genotypes. The following genotypes were genetically distinct: G40201, G40237, G40068, G40033 and G40063 which are recommended for further crosses, selection and population development.

Testing the impact of environmental change on hunter‐gatherer settlement organization during the Upper Paleolithic in western Iberia

ABSTRACTRecent cross‐disciplinary research in the Iberian Peninsula has revealed a synchronous pattern between rapid climate change and widespread cultural modifications during the Late Paleolithic. The beginning and development of each traditionally defined techno‐complex is thought to be associated with different environmental conditions. A main contrast is put on the impact of cold and arid conditions at the onset of the Last Glacial Maximum (LGM) and its coincidence with the development of blade/flake‐size projectiles and bifacial technologies, against the dominance of bladelet‐size backed points across more temperate and forested environments. Based on the long‐recognized assumption that lithic technology operates within the broader context of Pleistocene human ecodynamics, here we test the hypothesis that climate‐related lithic techno‐typological changes across the Upper Paleolithic are linked to modifications in land‐use patterns and settlement organization. We present statistical analysis comparing the Shannon–Weaver diversity index for retouched stone tool assemblages (used as proxy for site function) and locational parameters of a series of contexts from Central Portugal. The results show a trend of continuity and change between periods, with some of the most important deviations starting at the onset of the LGM, with the Heinrich Event 2 associated with patterns of technological diversification and biocultural expansion.

MORPHOMETRIC CHARACTERIZATION OF THE BREAD WHEAT VARIETY "ISKANDARIA" IN THE REGION OF AOUGROUT (ADRAR)

In Algeria, the diversity of wheat is poorly known for this reason an inventory has been made in a regionof southern Algeria "Adrar", specifically in the area of Aougrout, located south of the Timimoun region.Therefore, local varieties of bread wheat (Triticum aestivum) have been tried for morphologicalcharacterization. In this context, only one traditional bread wheat variety was studied using ninequantitative agromorphological traits and eight qualitative traits. The phenotypic diversity wasdetermined by the Shannon-Weaver diversity index (H’) at different levels. The estimated H’s showeda wide phenotypic variability for the different traits with an average H’ of 0.68 for the quantitative traitsand 0.34 for the qualitative traits. The results of this work revealed the great phenotypic diversity of thebread wheat variety (Iskandaria) studied and show that this local variety (whose genetic compositionremains to be studied more precisely) is mainly grown by traditional farmers, who conserve this geneticresource often on very small plots in oases and inaccessible land.

Nepalese foxtail millet [Setaria italica (L.) P. Beauv.] genetic diversity revealed by morphological markers

Foxtail millet [Setaria italica (L.) P. Beauv.] is among the oldest cereal grains grown from time immemorial in the Himalayan regions of Nepal. However, Nepalese farmers do not have any improved variety officially released due to lack of substantial research in this crop. A total of 41 foxtail millet accessions were characterized using phenotypic or morphological markers at National Agriculture Genetic Resources Centre (Genebank), Khumaltar (1360 m a.s.l.), Lalitpur, Nepal during 2015 summer to enhance the utilization of foxtail millet genetic resources. Seven quantitative and nine qualitative traits were recorded using standard descriptors of foxtail millet to assess the intra-specific diversity. Significant diversity was observed among the accessions as revealed by Shannon–Weaver diversity indices (H′) for quantitative traits and qualitative traits. Six elite landraces in Cluster-4 and Cluster-5 (three from Lamjung district, and one each from Gorkha, Humla and Jumla districts) produced average grain yield of 3136 kg/ha at Khumaltar condition with earlier maturity (average of 89 days), taller height (average of 172 cm) and thicker panicles (average width of 27 mm). These landraces were selected for further evaluation in the farmers’ field of mountain region due to their early maturity, higher yield potential, disease resistance and attractive panicles which could be considered as important genetic resources to develop climate resilient varieties to cope with the adverse effects of climate change.

Genetic diversity of Geoffroea decorticans , a native woody leguminous species from Atacama Desert in Chile

SUMMARY: Geoffroea decorticans (Fabaceae), chanar, is one of the few native tree species that are adapted to the ecologically limiting conditions from Atacama Desert. Despite its considerable value as a crop species, and important medicinal and food properties, the genetic variability of this plant has not yet been evaluated. The aim of this study was to analyze genetic diversity and degree of fragmentation in G. decorticans populations from six provinces in northern Chile. Genetic variability was assessed using eight ISSR and three RAPD primers, generating 97 % and 81 % polymorphic bands, respectively. AMOVA results based on nine populations showed high genetic diversity within populations (65 %) and moderate levels among populations (35 %). Moreover, genetic relationships among individuals provided evidence for the existence of two well defined clusters in the northern and southern regions of the Atacama Desert. A Mantel test showed a significant positive correlation between geographic and genetic distances (r = 0.58) in seven populations, indicating significant isolation-by-distance. Average Shannon Weaver diversity indices showed significantly lower values associated with Pachica, Copiapo river-mouth, Alto del Carmen and Vicuna populations relative to populations from San Pedro, Calama, Azapa and Copiapo. In this work, a combination of ISSR and RAPD methods provided high quality information to evaluate genetic variability, and could be used as an alternative method to identify and distinguish G. decorticans genotypes of interest. This work represents the first attempt to molecular characterization of G. decorticans in Chile, and its significance to future genetic research is discussed.

Forty years of dietary studies on barn owl (Tyto alba) reveal long term trends in diversity metrics of small mammal prey

Abstract The diet of predators is influenced by local conditions (e.g., characteristics of habitat and microhabitat, seasonality, prey availability) and therefore tends to change across time. In this paper, the diet composition of the barn owl (Tyto alba) in Italy was studied using a meta-analysis of 47 articles (covering 212 independent sites, with multiple surveys for some sites, thus giving a total of 290 datasets) between 1972 and 2012. General Linear Models were used to assess the effects of year and study site on four distinct diversity indices (species richness, dominance, Shannon-Weaver diversity and equitability). The year of data collection was a factor used in all analyses. Year had a greater effect than study site on all diversity indices, but the effect was not significant for the evenness and the species richness. However, dietary dominance increased significantly over the years, the Shannon-Weaver index of diversity decreased significantly over time, and equitability also decreased significantly over time. The relative abundance of various species of rodents did not increase/decrease progressively over the years, although there were inter-annual fluctuations. On the other hand, the relative abundance of insectivores tended to decrease with time, and there was a significantly negative correlation between year and the frequency of consumption of Sorex spp. and a marginally significant negative correlation for Crocidura leucodon.

Diverzitet i praćenje leta lisnih vaši kao potencijalnih vektora virusa uljane tikve u Srbiji

The fauna of aphids appearing on cucurbits, including oilseed pumpkin have been poorly investigated in Serbia. Yellow water traps were used to determine the diversity of aphid species visiting cucurbits in Serbia and to monitor their flight activity. During the years 2009 to 2011, a total of 1,447 specimens were collected and a total of 57 different aphid taxa were identified. In 2009, the highest total number of aphids were caught (755), followed by 203 and 489 aphids in 2010 and 2011, respectively. The most abundant species were Aphis fabae (15%), Myizus persicae (13.4%) and Acyrthosiphonpisum (11.7%), followed by Anoecia corni (6.4%) and Aphis gossypii (5.6%). All of them, except A. corni, are reported as efficient vectors of cucurbit viruses. These five species represent 52.1% of all aphid species collected within this study. Out of 57 taxa found in oilseed pumpkin crops, 17 are known as vectors of ZYMV, 18 of WMV and 15 of CMV. Generally, 25 out of a total of 57 taxa are known as vectors of at least one of three viruses present in Serbia. From total of 1,447 specimens collected during three years of investigation, 917 (63.4%) are vectors of at least one of three viruses. Individual oilseed pumpkin plants were frequently colonized by A. gossypii during all three years of investigation. Results of this study showed that Serbian oilseed pumpkin growing localities are grouped among medium to reach in aphidofauna, according to total Shannon-Weaver index values which varied from 1.8 to 2.8. The highest value of Shannon-Weaver (2.8) was recorded in the Bački Petrovac I locality in 2009, while the lowest Shannon-Weaver (1.8) was recorded in Kisač locality in 2010. The maximum values of Shannon-Weaver diversity index in almost all crops were recorded in the second week of investigation or in early stages of oilseed pumpkin growth when plants had 5-6 true leaves or were in flowering stage, when potential virus infection could lead to significant yield losses.

COMMUNITY STRUCTURE AND DIVERSITY OF MACROZOOBENTHOS IN QUARRY RIBNICA’S CREEK AS INDICATOR OF SURFACE WATER MANAGEMENT

Benthic macroinvertebrata (macrozoobenthos) are widely used for water quality assessments because they are considered as one of the best indicators of habitat quality in running waters, very conventionally called as „river health“. Benefits of research on macroinvertebrates include the quick assessment of biological resources for conservation purposes and the detection of water pollution. This research was performed in accordance with the EU Water Framework Directive (WFD). AQEM methodology was used for macrozoobenthos specimen collection from six sampling sites along quarry Ribnica’s main hydroecosystems – the Forest creek (quarry's water supply system) and the estuary of the river Ribnica (Mar-Sep, 2016). Laboratory analyses were carried out for the purpose of separation, counting and final taxonomic identification of organisms. Cluster analysis and diversity index computing were performed using BioDiversity Pro 2.0 software. Our findings suggest the existence of 15 taxa from classes Gastropoda, Hirudinea and Insecta with a total number of 454 sampled individuals. The Insecta class was the most numerous one with respect to the species found, including larvae of the orders Ephemeroptera, Plecoptera, Trichoptera and Diptera. Shannon-Weaver and Simpson diversity indices revealed highly developed communities of aquatic macroinvertebrates at all sampling sites. Water quality along quarry Ribnica based on macrozoobenthos indicator species of saprobity was found to be classified into moderate, low and non to very low polluted (Quality class I-II). Further long-term monitoring studies of macrozoobenthos are necessary in order to keep track of the good ecological status (GES) observed at quarry Ribnica’s aquatic ecosystems.

Evaluation of the Genetic Variation of Cowpea Landraces (Vigna unguiculata) from Western Cameroon Using Qualitative Traits

Characterization of the genetic diversity and analysis of the genetic relationship between accessions of a crop species is a key step in breeding superior cultivars. The main objective of the hereby study was to determine the genetic variation between 30 cowpea accessions collected throughout the eight divisions of the Western Region of Cameroon using qualitative traits. Phenotypic variation of these accessions was evaluated using diversity indices and cluster analyses. A total of twenty qualitative traits were used for the study. Fifteen of them (75%) were polymorphic, displaying each at least two phenotypic classes. The monomorphic characters were growth pattern, leaf color, leaf hairiness, plant hairiness and pod hairiness, each with only one phenotypic class. Results showed a relatively significant level of genetic diversity among the studied cowpea accessions. Overall, the average of the observed and effective number of phenotypic classes per qualitative trait were Na = 2.350 and Ne = 1.828 respectively. The Nei’s genetic diversity and the Shannon weaver diversity index were He = 0.369, ranging from zero (monomorphic trait) to 0.655 (growth habit) and H’ = 0.609, ranging from zero (monomorphic trait) to 0.996 (seed crowding), respectively. The dendrogram constructed from the twenty qualitative traits revealed 05 accessions clusters with the number of accessions in each cluster varying from one to eleven. Information obtained from this study is likely be useful for future cowpea breeding program.

Comparison of benthic indices for the evaluation of ecological status of three Slovenian transitional water bodies (northern Adriatic)

Benthic indicators are important tools for the classification of coastal and transitional water bodies. The aim of the work was to assess for the first time the Environmental Status (ES) of Slovenian transitional waters, comparing the following biotic indices: richness, Shannon-Weaver diversity, AMBI, M-AMBI, BENTIX and BITS indices. A total of 13 stations were sampled with a Van Veen grab, in three ecosystems in the northern Adriatic. Samples were sieved and sorted, invertebrates identified and counted. The anthropogenic impact was estimated with professional judgement. Richness and diversity showed a good response to anthropogenic pressure. Conversely, indices based on sensitivity/tolerance groups did not showed a clear distinction between more and less impacted ecosystems. In particular BENTIX underestimated the ES, while with BITS there was a overestimation. The best evaluation was obtained with M-AMBI, because even if based on a sensitivity/tolerance approach, it considered also the structural aspect of the community.

English

Characterization of landraces is central to any conservation measures devised for sweet potato in Malawi. Studies were therefore conducted using seven morphological descriptors and farmers’ indigenous knowledge systems (IKS) to investigate the phenotypical diversity of 286 landraces and 35 introductions of sweet potato from the north, south east and lower Shire. The accessions were planted in a check plot design at Bvumbwe Agricultural Research Station. The results showed that farmers’ knowledge (IKS) is a means for preliminary characterization of accessions as evidenced by elimination of 75 duplicate accessions by 12 farmers. Analysis of variance (ANOVA) showed that all accessions and populations were phenotypically variable (p≤0.01) and Chi-square test of the morphological descriptors used in the study varied significantly among the three eco-geographical areas and among the landraces and introductions (p≤0.05 and p≤0.01), implying high variability of the accessions. However, the accessions clustered at 50% dissimilarity and generally irrespective of eco-geographical origin, signifying some similarity probably due to gene flow. Shannon Weaver Diversity Index (H’) indicated that different traits had different source areas of highest diversity which were significantly different (p≤0.05); nonetheless Shire Valley had the highest mean diversity for all traits (H’=0.67) which was significantly different from the other two populations (p≤0.05) inferring that the lower shire would be ideal for in situ conservation of sweet potato diversity. Key words: Field evaluation, germplasm, phenotype, population, root crop, variability.

Genetic diversity of improved varieties of intraspecific (O. sativa and O. glaberrima) and interspecific (O. sativa × O. glaberrima) rice

Information on genotype diversity and interrelationships is essential for germplasm management, crop improvement and seed production. In this study the diversity of a collection of 36 rice accessions comprising of Oryza sativa L., O. glaberrima Steud. and interspecific rice (O. sativa × O. glaberrima) was assessed using 24 agro-morphological and 27 microsatellite markers. The collection was composed mainly of improved cultivars and a few landraces which are adapted to the upland ecology in West Africa. The average Shannon–Weaver diversity index value (H′) was 0.23. The highest diversity was found in O. sativa group Indica (H′ = 0.32), and the lowest (H′ = 0.18) in O. glaberrima. Interspecific rice had intermediate diversity. There were 321 alleles with an average of 11.9 alleles per locus and an average major allele frequency of 0.29 per locus. The average gene diversity value was 0.81 and polymorphism information content was 0.80 per locus. Diversity indices for interspecific rice were intermediate between O. sativa and O. glaberrima, but closer to O. sativa group Japonica. Accessions comprised of two populations which corresponded to O. sativa group Indica and O. sativa group Japonica. Interspecific rice accessions were dispersed between the two groups.

Is It Still Necessary to Continue to Collect Crop Genetic Resources in the Mediterranean Area? A Case Study in Catalonia

Crop genetic resources have been extensively collected in Europe in the last century, creating large, publicly available ex situ collections. While this huge genetic diversity is often underutilized, in recent decades, several initiatives have emerged at the local level to collect germplasm cultivated on farm. Uncoordinated actors often carry out these collecting missions without considering previously collected data. To explore whether new collecting missions are likely to be worthwhile, we studied the crop genetic resources conservation network in Catalonia by analyzing the passport data and geographical distribution of germplasm stored in seed banks. Moreover, to determine whether this germplasm was representative of the diversity cultivated on farm, we performed new collecting missions in four randomly selected areas in the European Union’s Natura 2000 network and compared the results with the ex situ databases. Seed banks currently hold a large germplasm collection (2931 accessions), although most materials are conserved in private collections without regulated systems for seed regeneration and are not present as duplicates in the National Inventory. One important shortcoming of the ex situ network is that the germplasm conserved ex situ shows a low geographical coverage, representing only 35.3% of the municipalities in Catalonia. Our new missions allowed us to collect 234 accessions, mostly tomatoes (17.5%) and beans (16.2%). The ecological indicators’ richness (both at species (S) and variety (V) levels), total abundance (A), and the Shannon-Weaver diversity index calculated at species (H2, considering the different accessions of each variety as a single population) and variety levels (H3, considering the intra-varietal genetic diversity) were higher in the newly collected germplasm than in the ex situ collections, suggesting that seed banks do not accurately represent the genetic diversity still cultivated on farm. Moreover, some important landraces from each area were absent or underrepresented in the ex situ collections. Thus, it is necessary to continue to devote efforts to collecting germplasm; better organization between actors and targeting specific species/varieties can increase the efficiency of new collecting missions. As a conclusion, we propose different criteria to guide new missions and to improve the network’s conservation activities.

Impact De L’exploitation Artisanale De La Sabliere De Toutsang Sur La Structure Des Communautes De Macroinvertebres Du Cours D’eau Doulahang A Dschang (Ouest Cameroun)

The impact of wastewaters from the Toutsang sandpit (Dschang), both on water parameters and on benthic macro-invertebrate community structure of the Doulahang stream was studied from March 2015 to February 2016 on a monthly basis in three sampling stations named TS1, TS2 and TS3. The physico-chemical analysis were carried out according to standard protocols while the benthic macro-fauna was harvested using a haze net of 30 cm side and 400 μm mesh size. The analysis of physico-chemical parameters revealed that the introduction of wastewater from the sandpit at the TS2 station led to an increase of the temperature, conductivity, total dissolved solids, salinity, suspended matter, turbidity and colour. The wildlife inventory identified 63 taxa divided into 4 phyla, 6 classes, 13 orders and 31 families. The lowest values of the taxonomic richness (18 taxa, against 46 taxa and 47 taxa respectively to stations TS1 and TS3), the Shannon diversity index (2.48 bits / ind.) and the Pielou's evenness (0.62) were observed at station TS2 which received wastewaters from the sandpit. Similarly, the low values of the richness and abundance of the pollutionsensitive groups (Ephemeroptera-Trichoptera-Odonata) were recorded in this station. Significant negative correlations were found between some metrics (total taxonomic richness, taxonomic richness of the Diptera, Richness of Ephemeroptera-Trichoptera-Odonata, Taxonomic richness of insects, Relative abundance of Ephemeroptera-Trichoptera-Odonata, Shannon Weaver diversity index, Pielou's evenness) descriptors of the structure of benthic macro-fauna communities and physico-chemical parameters indicative of physical pollution such as turbidity, suspended matter and colour.

Diversity in proso millet (Panicum miliaceum L.) landraces collected from Himalayan mountains of Nepal

Proso millet (Panicum miliaceum L.) is one of the oldest cereal grains cultivated in the north-western part of Nepal. Not a single proso millet variety has been released so far for cultivation in Nepal. To assess the genetic diversity of proso millet conserved in the National Agriculture Genetic Resources Centre, 42 accessions of proso millet were characterized in Khumaltar (1360 m a.s.l.), Lalitpur in 2015 that were collected from the Humla (1900–2800 m a.s.l.) and Jumla (2300–2600 m a.s.l.) districts of the Western Himalayas of Nepal. Seven quantitative and nine qualitative traits were recorded using standard descriptors. The accessions were found to be diverse using Shannon–Weaver diversity indices (H′) for the quantitative traits of days to heading and maturity, plant height, panicle length, panicle exertion, flag leaf length and grain yield, whereas low diversity was observed for the qualitative traits of leaf sheath colour, flag leaf angle, grain shape, and grain colour, and no diversity was observed for leaf pubescence. The accessions were grouped in five clusters where an accession in Cluster-5 and six accessions in Cluster-4, all from Humla, were found to be high-yielding, early-maturing and of taller plant height. In contrast, 4 accessions in Cluster-2 (3 from Jumla) were low-yielding, late-maturing and of shorter plant height. Accessions H237, H176, H311, H489, H490, H643 and H653, all from the Humla district, performed better in the preliminary evaluation. Although these accessions could be used for future breeding to develop climate-resilient varieties, the genebank could employ an innovative method of using participatory diversity kits to promote farmer selection for immediate benefits.

Diversity of Cassava (Manihot esculenta Crantz) Cultivars in the Traditional Agriculture of Togo

Cassava (Manihot esculenta Crantz) is one of the major root and tuber crops contributing to food security and poverty alleviation in Togo. Unfortunately, its cultivars diversity is still not known and has even never been assessed and documented countrywide for use in breeding and development programs. To fill this gap of knowledge, 40 villages randomly selected within cassava production zones in Togo were surveyed using participatory rural appraisal. A total of 168 farmer-named cultivars were recorded. Their number varied from 1 to 15 (7 on average) per village. The highest diversity in the surveyed area was found at M'poti (15 cultivars) in Centrale region while the lowest diversity was found at Awounadjassi (1 cultivar) in plateaux region. The Shannon-Weaver diversity index (H) was estimated at 3.59 bits.The folk nomenclature was analysed and understood. The distribution and extent analysis revealed that per village few cultivars (0 to 4) are produced by many houses on large areas. The rates of cultivars abandonment risk varying from 14% to 86% (44.87% on average) depending on the village. Low productivity, late maturity and toxicity were the main abandonment reasons reported by farmer. Subject to synonymy, the participatory evaluation of the 168 cultivars inventoried yielded 37 tolerant to poor soils, 29 tolerant to high soil moisture (adaptability to lowlands), 58 tolerant to drought and 57 tolerant to weeds.The majority (132 cultivars) of cultivars were well adapted to all type of soil, 119 were able to make good quality of chips whereas 123 cultivars were non-toxic. As cassava is a vegetative propagated crop and cultivars vernacular names vary across ethnic groups, it was recommended that the diversity be collected and fully characterized and synonymies clearly established. The results were found as of high importance for research and development actions including ex situ and in situ on farm conservation.

Re-defining the yam (Dioscorea spp.) core collection using morphological traits

AbstractDevelopment of core collection representing the diversity in the entire germplasm creates a better access and enhanced utilization of the main collection thus allowing rapid evaluation in crop improvement programs. Core collections are dynamic in nature and needs revisiting when additional germplasm and information becomes available. In the current study, an attempt was made to re-define the previously developed yam (Dioscorea spp) core collection using 56 morphological traits. Information on additional acquired germplasm and presence of duplicates or mislabelled accessions in the entire collection was also used. The re-defined core collection consisted of 843 accessions and represented about 20% of the entire collection. It included six Dioscorea species, of which accessions of Dioscorea rotundata are in the majority (73.54%) followed by Dioscorea alata (21.35%), Dioscorea bulbifera (1.66%), Dioscorea cayenensis (1.42%), Dioscorea dumetorum (1.42%) and Dioscorea esculenta (0.59%). The Shannon weaver diversity index and principal component analysis revealed the maximum diversity captured in the core from the base collection. This re-defined core collection is more valuable than the original core since it represents true-to-type accessions ensuring reliability for enhanced utilization of germplasm in yam improvement programs.