Thonningia sanguinea Vahl. (Balanophoraceae) in Southern Nigeria: II. Patterns of Genetic Diversity and Population Structure within and between Populations (original) (raw)
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Proceedings of 7th NSCB Biodiversity Conference, 2020
Thonningia sanguinea Vahl. Balanophoraceae, a cryptic parasitic plant, is among the poorly understood, yet understudied afro-tropical endemic taxa. This study assessed the conservation status and identified possible threats to the survival of T. sanguinea in southern Nigeria. Data on the distribution, population and possible threats were collected from field survey in twenty-one (21) selected locations. Additionally, 104 residents were interviewed in the study areas. Overall, forty-nine (49) T. sanguinea populations were identified across the selected locations. The results showed that host tree species such as Guarea cedreta (Meliaceae), Hevea brasiliensis (Euphorbiaceae), Lophira alata ((Ochanaceae) Musanga cecropiodes (Urticaceae), Myrianthus arboreus (Urticaceae), Ricinodendron heudelotii (Euphorbiaceae), Theobroma cacao (Malvaceae) supported the T. sanguinea populations in the area. However, threats to T. sanguinea populations were habitat loss and degradation, bushfire, and destructive feeding by some forest ruminants. Although, from the IUCN Red list analysis, the status of T. sanguinea is Near-threatened (NT), findings from this study suggests that in the near future it could qualify for a threatened category from continued threat to the survival. It is recommended, therefore, that the identified T. sanguinea populations from this study should be protected and allowed to proliferate with the host plant species.
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Sour jujube or wild jujube (Ziziphus acidojujuba), considered as the ancestor of cultivated jujube, is an economically and ecologically important species. However, little is known about the population genetics of this species across China. In this study, we detected genetic variation among 874 individuals from 31 natural populations covering the most representative distribution sites of sour jujube in China using nine simple sequence repeat markers. By Bayesian, phylogenetic, and principal component analyses, two genetic groups of sour jujube in China were identified. One group was almost from east of the Taihang Mountains in the North China Plain, and the other was from west of the Taihang Mountains in the Loess Plateau. The high levels of genetic diversity (H E =0.659 and H S =0.674) was detected in these populations, and the moderate differentiation was found among populations (F ST =0.091, R ST = 0.068, G′ ST =0.271). Populations from the North China Plain harbored higher genetic diversity (H E =0.686 and H S =0.706) than those from the Loess Plateau (H E =0.646 and H S =0.659) (P<0.05). Analysis of molecular variance revealed that within-population genetic variation (88 %) was higher than that among populations (12 %). High gene flow (Nm= 6.572) and weak correlation between genetic and geographical distances (r 2 =0.026, P>0.05) suggested that gene flow occurred frequently among the populations. Understanding the genetic diversity and population structure could benefit germplasm conservation, genetic improvement, and systematic utilization of Ziziphus.
STUDIES ON THONNINGIA SANGUINEA VAHL. (BALANOPHORACEAE) IN SOUTHERN NIGERIA: RANGE AND HOST PREFERENCE, 2019
Studies on the host-parasite relationship are intrinsically linked with the nature of parasitic plants. No such records have been recorded for Thonningia sanguinea (Balanophoraceae), a rare, cryptic, obligate holoparasitic plant endemic to tropical Africa. This study reports on its host range and preference in Southern Nigeria. Its presence and current distribution ranges were plotted from reconnaissance surveys conducted across selected forested areas in Southern Nigeria, comprising, national parks, forest reserves, and community-managed forests. To detect specific hosts, soil excavation leading from parasite to host was conducted. The results showed a broad host range with a special preference for native trees and members of the Euphorbiaceae and Urticaceae. Among the common host trees were: Guarea cedrata (Meliaceae), Lophira alata (Ochanaceae), Musanga cecropiodes (Urticaceae), Myrianthus arboreus (Urticaceae), and Ricinodendron heudelotii (Euphorbiaceae). Only Hevea brasiliensis and Theobroma cacao were of exotic origin. Lophira alata was the most susceptible infected host plant with a percentage infestation rate of 28.77, while Musanga cecropiodes had the highest percentage occurrence as host with 31.57 %. This finding could have significant implications on the conservation status of the plant, which accounting for current IUCN status is Not Evaluated (NE). In situ conservation is however recommended.
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Random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers were used to compare genetic diversity of 17 accessions of Clitoria ternatea (Fabaceae) populations, collected from nine different states of India. The populations included three different flower colours viz., blue, white and white with blue tinge. Twentythree RAPD primers and eighteen ISSR primers amplified a total of 137 and 105 reproducible DNA fragments, respectively with fragment sizes ranged from 150 to 3,000 bp. ISSR showed higher polymorphism (29.52 %) in comparison to RAPD (27.73 %). In RAPD analysis, maximum polymorphic information content value (0.66) was observed in primer OPC 10 but in ISSR study, it was (0.55) in primer UBC 889. Jaccard's coefficient of similarity showed that pairwise genetic similarity coefficients ranged between 81 and 97 % in RAPD analysis, whereas 80 and 98 % in ISSR analysis, which were in close range to each other. Similarly, clustering pattern showed same trend in both the markers analysis which also revealed that all the accessions were grouped according to their geographical locations rather than on the basis of different flower colours. Mental Z test indicated highly significant co-relation between geographical distance and genetic distance among the populations (r = 0.8321, P \ 0.01). Genetic similarity between populations showed very high values (\80 %) indicating low genetic variation within and among the populations. The narrow genetic base within the populations was either due to the exotic origin or due to self pollinated behaviour of the species which restrict gene flow within and between populations.
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Genetic diversity within and among populations of a
Erodium paularense Fern. Gonz. & Izco (Geraniaceae) is a perennial, endemic species of central Spain. The restricted distribution of its three populations has made it necessary to consider measures for conservation. Random amplified polymorphic DNA markers were used to determine genetic variation among and within populations. Sixty-three per cent of the bands were polymorphic. No population-specific marker was identified. Cluster analysis based on Jaccard's coefficient of all the individuals grouped most of them according to the present populations. Within-population variability was of a similar order in the three populations. Highly significant genetic differences between populations were detected through A M O V A. Within population diversity contributed 80435% to the species diversity, a value typical of an outbreeding plant.