Subject: Life Sciences, Genetics Keywords: genetic diversity; Dioscorea praehensilis; SSR markers; Ghana
Online: 8 March 2020 (14:55:19 CET)
Dioscorea praehensilis Berth is one of the wild yam species resistance to many yam disease (yam anthracnose disease and yam mosaic virus) grow in Ghana especially in the cocoa grown regions of the country. It is a crucial crop that has been known to contribute to poverty reduction and food gap. Genetic diversity in this yam species has been discovered to be eroding and neglected. In this study we evaluated the genetic diversity among 43 D. praehensilis collected from Ghana using simple sequence repeat (SSR). Using 11 SSR marker, a total of 99 number of alleles were generated with an average of 8.48 alleles per locus. The mean gene diversity was 0.81, mean polymorphism information content was 0.82 while mean Shannon information index was 1.94. Principal coordinate analysis (PCoA) revealed a contribution of 40.16% of the first three coordinate axes and grouped the 43 morphotypes into 2 groups while hierarchical cluster through UPGMA revealed the presence of 3 main clusters. Molecular variance (AMOVA) alongside the Fst revealed low genetic diversity and differentiation among accessions and population. Result of this study assess the genetic diversity and will facilitate the use D. praehensilis as sources of resistance gene into yam breeding program.
ARTICLE | doi:10.20944/preprints202107.0305.v1
Subject: Biology, Anatomy & Morphology Keywords: Dioscorea spp.; flow cytometry; chromosome counting; ploidy level; DArTseq
Online: 13 July 2021 (11:29:47 CEST)
Yam (Dioscorea spp.) is a monocotyledonous herbaceous vine plant grown in the tropics and subtropics. It is a multi-species plant with varied intra- and interspecific ploidy levels. Of the 600 species, 11 are cultivated staple supporting the livelihood of over 300 million people. The paucity of information on ploidy and the genomic constitution is a significant challenge to the crop’s genetic improvement through crossbreeding. The objective of this study was to investigate the ploidy levels of 236 accessions across six cultivated and two wild species using chromosome counting, flow cytometry and genotyping-based ploidy determination methods. Results obtained from chromosome counting and genotyping-based ploidy determination were in agreement. In majority of the accessions, chromosome counting and flow cytometry were congruent, allowing future rapid screening of ploidy levels using flow cytometry. Among cultivated accessions, 168 (71%) were diploid, 50 (21%) were triploid, and 12 (5%) were tetraploid. Two wild species included in the study were diploids. Resolution of ploidy level in yams offers opportunities for implementing successful breeding programmes through intra- and inter-specific hybridization.
ARTICLE | doi:10.20944/preprints202207.0267.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Dioscorea; yield stability; environments; genotype; dry matter; disease resistance; Uganda
Online: 18 July 2022 (10:56:10 CEST)
Often yam varieties grown in different agro-ecologies show differential responses across production environments, a term known as genotype-by-environment interaction. Genotype-by-environment interaction makes selecting the best genotypes under varied production environments more complex. This study tested twenty yam genotypes evaluated in six test environments to assess genotype, environment, and the interaction between genotypes and environmental effect for tuber yield, yam mosaic virus, and dry matter content. The experiments were conducted in two seasons across three locations in Uganda using a randomized complete block design with three replications. The results showed a significant effect (p ≤ 0.001) for genotype (G), environment (E), and genotype by environment interaction for all the traits. Serere 2021 and Namulonge 2021 were identified as the most discriminating and representative environments for testing the yam mosaic virus, respectively. Serere 2021 was recognized as the most discriminating environment, whereas Arua 2021 was identified as the closest to an ideal environment for assessing yam tuber yields. The tested genotypes also exhibited high resistance to yam mosaic virus disease, high tuber yields, and high dry matter content. Genotypes UGY16020, UGY16034, UGY16042, and UGY16080 demonstrated great resistance to yam mosaic virus disease, high yielding, and considerable dry matter content and are thus potential parents for yam improvement. Further evaluation of the four genotypes should be done under farmers' production systems for selection, improvement, and release as new yam varieties for Uganda
ARTICLE | doi:10.20944/preprints201806.0398.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Allantoin; Chinese Yam; C2C12 cells; Dioscorea batatas; Dioscoreae Rhizoma; Myoblast differentiation; Mitochondrial biogenesis
Online: 25 June 2018 (16:32:43 CEST)
The present study was conducted to investigate the effects of rhizome extract of Dioscorea batatas (Dioscoreae Rhizoma, Chinese Yam) and its bioactive compound, allantoin, on myoblast differentiation and mitochondrial biogenesis in skeletal muscle cells. Yams were extracted in water and the extract was analyzed by HPLC. The expression of C2C12 myotubes differentiation and mitochondrial biogenesis regulators were determined by reverse transcriptase (RT)-PCR or Western blot. The glucose levels and total ATP contents were determined by glucose consumption, glucose uptake and ATP assays, respectively. Treatment with yam extract (1 mg/mL) and allantoin (0.2 and 0.5 mM) significantly increased of MyHC expression compared with non-treated myotubes. Yam extract and allantoin significantly increased the expression of mitochondrial biogenesis regulating proteins, PGC1?, Sirt-1, NRF-1, and TFAM, as well as the phosphorylation of AMPK and ACC in C2C12 myotubes. Furthermore, yam extract and allantoin significantly increased the glucose uptake levels and the ATP contents. Finally, HPLC analysis revealed that the yam extract contained 1.53% of allantoin. Yam extract and allantoin, stimulated myoblast differentiation into myotubes and increased energy production through upregulation of mitochondrial biogenesis regulators. These findings indicate that yam extract and allantoin can help to prevent the skeletal muscle dysfunction through stimulation of energy metabolism.