Diversity analysis of Moroccan carob ("Ceratonia siliqua" L.) accessions using phenotypic traits and RAPD markers

Diversity analysis of moroccan carob (Ceratonia siliqua L.) accessions using phenotypic traits and RAPD markers. The carob (Ceratonia siliqua L.) is a perennial leguminous (Caesalpinioideae) that grows as an evergreen shrub or tree. It¿s an important component of the Mediterranean vegetation and its adaptation in marginal soils of the Mediterranean regions is important environmentally and economically. Phenotypic and genetic diversity among 10 Ceratonia siliqua accessions coming from different areas of Morocco were studied with morphometric and RAPD approaches. The analysis of discriminative fruit characters showed highly significant differences among these accessions, the closely related ones have a similarity level less than 65%. No molecular studies have been carried out so far on Ceratonia siliqua. To provide markers useful for molecular diversity study of the carob tree, genomic DNA extraction and amplification conditions were finalized and 67 arbitrary primers were screened. 52 of them showed clearly reproducible banding patterns. The analysis of RAPD profiles revealed a high degree of genetic diversity within these carob accessions and enabled each of them to be uniquely fingerprinted. Overall, in our study we note that morphological relationship between carob accessions is deeply different to their molecular relationship. Concerning the distribution of the accessions according to their geographical origin, clustering based on RAPD data revealed a rough distribution of theses accessions. Indeed, Sidi Bou Ottman, Demnate and Essaouira accessions coming from the south of Morocco seem to be linked in the PCA plot. However, two geographically distant accessions, Aïn Sfa and Ouazzane coming from the north (about 700 Km) were clustered with Essaouira and Demanate - Sidi Bou Ottman, respectively.Analyse de la diversité des accessions du caroubier marocain (Ceratonia siliqua L.) utilisant des traits phenotypiques et des marqueurs RAPD. Le caroubier (Ceratonia siliqua L.) est une légumineuse pérenne (Caesalpinioideae), à feuillage persistant et pouvant croître entant qu¿arbrisseau ou arbre. C¿est un composant important de la végétation méditerranéenne et son adaptation aux sols marginaux des régions méditerranéennes est d¿une grande importance écologique et économique. La diversité phénotypique et génétique au sein de 10 accessions de caroubier provenant de différentes régions du Maroc a été étudiée par des approches morphométriques et moléculaires (RAPD). L¿analyse des caractères morphologiques discriminants du fruit a montré des différences hautement significatives au sein des accessions, puisque les apparentées d¿entre elles n¿ont approximativement que 65% de similarité. Jusqu¿à nos jours, aucune étude moléculaire n¿a été entreprise sur Ceratonia siliqua. Pour mettre à disposition des marqueurs utiles pour l¿étude de la diversité moléculaire du caroubier, l¿extraction de l¿ADN génomique et les conditions de l¿amplification ont été mises au point et 67 amorces arbitraires ont été criblées. 52 d¿entre elles ont montré clairement des profils de bandes reproductibles. L¿analyse des profils RAPD a révélé une diversité génétique de haut niveau entre les accessions de caroubier ce qui a permis à chacune d¿elles d¿être distinguée génétiquement de façon singulière. De manière générale, nous avons noté que la relation morphologique entre les accessions du caroubier est profondément différente de leur relation moléculaire. Concernant la distribution des accessions selon leur origine géographique, le regroupement basé sur les données de la RAPD a révélé une distribution grossière. En effet, les provenances de Sidi Bou Ottman, Demnate et Essaouira, originaires du sud de Maroc, semblent être liés par l¿analyse des composantes principales (PCA). Cependant, deux accessions géographiquement distantes, Aïn Sfa et Ouazzane, originaires du Nord (approximativement 700 Kms) ont été liées avec Essaouira et Demanate - Sidi Bou Ottman, respectivement

Combining High Yields and Blast Resistance in Rice (Oryza spp.): A Screening under Upland and Lowland Conditions in Benin

The future security of the supply of rice for food in Africa depends on improving the level of local production to achieve self-sufficiency. In order to cope with the existing gap between production and actual demand, combining a high level of rice blast tolerance and a high-yield potential is necessary. The current study was conducted under upland and lowland conditions in Benin to gain insight into the performance of selected blast-resistant accessions along with some currently grown varieties. This study revealed a high phenotypic variability among these accessions. Furthermore, differences in the performance of these accessions under lowland and upland conditions were observed. Principal component analysis showed their grouping in three clusters. The analysis also demonstrated a high yield potential among the blast-resistant rice accessions whether they were Oryza sativa or O. glaberrima. Furthermore, there was a significant correlation between yield and both spikelet fertility and growth cycle duration. In conclusion, the present study identified promising rice accessions for future breeding. High phenotypic variability in combination with interesting traits can help to develop new resilient varieties. Finally, when the traits correlate with yield, they can be used as markers for an early screening method for identifying promising accessions at an early stage

Origins of the amphiploid species Brassica napus L. investigated by chloroplast and nuclear molecular markers

Background: The amphiploid species Brassica napus (oilseed rape, Canola) is a globally important oil crop yielding food, biofuels and industrial compounds such as lubricants and surfactants. Identification of the likely ancestors of each of the two genomes (designated A and C) found in B. napus would facilitate incorporation of novel alleles from the wider Brassica genepool in oilseed rape crop genetic improvement programmes. Knowledge of the closest extant relatives of the genotypes involved in the initial formation of B. napus would also allow further investigation of the genetic factors required for the formation of a stable amphiploid and permit the more efficient creation of fully fertile re-synthesised B. napus. We have used a combination of chloroplast and nuclear genetic markers to investigate the closest extant relatives of the original maternal progenitors of B. napus. This was based on a comprehensive sampling of the relevant genepools, including 83 accessions of A genome B. rapa L. (both wild and cultivated types), 94 accessions of B. napus and 181 accessions of C genome wild and cultivated B. oleracea L. and related species. Results: Three chloroplast haplotypes occurred in B. napus. The most prevalent haplotype (found in 79% of accessions) was not present within the C genome accessions but was found at low frequencies in B. rapa. Chloroplast haplotypes characteristic of B. napus were found in a small number of wild and weedy B. rapa populations, and also in two accessions of cultivated B. rapa 'brocoletto'. Whilst introgression of the B. napus chloroplast type in the wild and weedy B. rapa populations has been proposed by other studies, the presence of this haplotype within the two brocoletto accessions is unexplained. Conclusions: The distribution of chloroplast haplotypes eliminates any of the C genome species as being the maternal ancestor of the majority of the B. napus accessions. The presence of multiple chloroplast haplotypes in B. napus and B. rapa accessions was not correlated with nuclear genetic diversity as determined by AFLPs, indicating that such accessions do not represent recent hybrids. Whilst some chloroplast diversity observed within B. napus can be explained by introgression from inter-specific crosses made during crop improvement programmes, there is evidence that the original hybridisation event resulting in to B. napus occurred on more than one occasion, and involved different maternal genotypes

Reproductive mechanisms and pollen characterization in some accessions of an underutilized legume: (Sphenostylis stenocarpa Hochst Ex. A. Rich) harms

Studies on flowering, pollen, pod and seed characters, germination rate and seed set percentage were carried out on twenty five accessions of African Yam Bean (AYB). Self compatibility tests confirmed all the accessions as obligate selfers, while the reciprocal crosses were not successful. Germination rate, percentage seed set and pollen fertility were observed to be high in the accessions. Correlation analysis among the reproductive traits revealed that pod length, pod width, number of locules per pod and number of seeds per pod contributed significantly to the percentage seed set in all the accessions. Pollen fertility and seed viability were also observed to be high in all the accessions except in TSs23 where low pollen fertility, low seed viability and low percentage seed set were recorded. All the accessions produced tricolporate pollen grains. Pollen size ranged from 66.15 μm in TSs40 to 82.75 μm in TSs119, pollen fertility ranged from 53.39% in TSs23 to 95.30% in TSs119, seed set ranged from 83.32% in TSs90, 89.21% in TSs23 and 95.72% in TSs3. The germination rate ranged from 59.68% in TSs23 to 99.03% in TSs22. The percentage moisture content ranged between 4.38% in TSs22 and 11.43% in TSs119. Key words: Pollen characters, seed set, germination rate, self compatibility

Molecular Verification of the UK National Collection of Cultivated Liriope and Ophiopogon Plants

open access articleA collection of cultivated Liriope and Ophiopogon plants was established in 1996–1998 and subsequently hosted at a horticultural college. Uncertainties about the identification of the accessions, compounded by potential errors in propagation and labelling have led to waning confidence in the identities of the plants in the collection. The potential for using DNA barcoding to determine the species identities of the accessions was investigated. The DNA barcode regions of the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) and nuclear ribosomal internal transcribed spacer (nrITS) were amplified. DNA sequence analysis allowed the sequences of the accessions to be compared to reference sequences in public databases. A simple haplotype map of the characteristic polymorphic positions in the rbcL regions was used to clearly distinguish between the two genera and assign Ophiopogon accessions to individual species or sub-groups of species. The ITS sequence data confirmed these genus and species assignations and provided greater resolution to distinguish between closely related species. The combination of two DNA barcodes allowed most of the accessions to be assigned to individual species. This molecular verification confirmed the identity of about 70% of the accessions, with the remaining 30% demonstrating a range of mistaken identities at the species and genus level

Evaluation of Rice Cultivars for Resistance to \u3ci\u3eCnaphalocrocis medinalis\u3c/i\u3e Guenée (Lepidoptera: Pyralidae)

Greenhouse screening of 17,914 accessions of rice, Oryza sativa L., from 62 countries identified 115 accessions from 10 countries having resistant or moderately resistant reactions to Cnaphalocrocis medinalis Guenée. Of 264 wild rices (Oryza spp.) screened, 10 (3.7%) were resistant. Several breeding lines having “Ptb33” and “W1263” as donor parents were moderately resistant. All of the resistant accessions are from regions where C. medinalis is an important pest, except for one accession from Italy, which is beyond the range of C. medinalis distribution

Morphological intraspecific variabilities in African yam bean (AYB) (Sphenostylis stenocarpa Ex. A. Rich) Harms

Intraspecific variabilities in 25 IITA accessions of African yam bean (AYB) (Sphenostylis stenocarpa Ex. A. Rich.) Harms were assessed through characterization of 36 morphological characters. The intraspecific variabilities among the accessions were evaluated by the following statistical analysis tools: Analysis of Variance (ANOVA), principal component and cluster analysis (Semi - partial Rsquared method). The accessions showed significant differences in a number of morphological characters and the P values indicated significant differences (p � 0.0001) in 27 characters. Statistical analysis showed that terminal leaflet length, terminal leaflet width, peduncle length, pod length, pod width, number of locules per pod and number of seeds per pod contributed significantly to seed set percentages in all the studied populations. Cluster analysis on the morphological data clustered the accessions into six distinct groups with pod and seed traits contributing significantly to the grouping. Pod lengths, number of seeds per pod and seed weight were observed to be useful characters for genetic improvement of AYB