A Comparative Assessment Of Taro{Colocasia Esculenta L. (Schott)} Phenotypic Corms/Cormels Characteristics Among Kenya And Tarogen Core Taro Collections For Taro Crop Improvement And Breeding

Determination of qualitative phenotypic taro cormels characters were scored based on the key International Plant Genetic Resources Institute (IPGRI) descriptors for taro (IPGRI, 1999). Twenty five taro germplasm each from Kenya and Tarogen core taro collections from Pacific Island Communities were used for this research study. These characteristics were as follows: Corm shape, Corm cortex color; Corm flesh color; Number of sprouting suckers; Corm sucker length; Corm weight; Corm length; Corm diameter; Number of cormels; Corm branching and cormel root colour. Shannon’s Diversity Index was used to calculate the diversity for the qualitative characters that showed polymorphism in various traits. A two-way analysis of variance (ANOVA) was used to analyze cormels genotypic agronomic performance among Kenyan and the Pacific Islands tarogen collections. The analyses of variance were tested at 0.05 level of significance. In Kenya, the corm characters with highest diversity value were corm shape (1.399), corm cortex color (1.204) and corm flesh color (0.973) while Tarogen core taro collections from Pacific Islands community showed similar variations with the corm shape leading with diversity value of 1.357. The application of analysis of variance test at (p>0.00) revealed a significant difference between corms/cormels and yields of taro accessions with reference to taro genotype performance characters and yields. These findings have shown that there exists a high significant difference between taro genotype agronomic cormels characters and yields between Kenya and PITCs taro collections. The application of analysis of variance test at (p>0.00) revealed a significant difference between taro cormels characters with reference to yield performances

Comparative analysis of phenotypic characterization of Kenya and Pacific Islands tarogen germplasm collections Colocasia esculenta L. (Schott)

Fifty accessions of taro germplasm collections Colocasia esculenta L. Received: 15 November, 2014 (Schott) were collected from Kenya and Pacific Islands tarogen germplasm collections. Twenty five accessions of Kenyan taro germplasm were Accepted: 17 December, 2014 collected from Western, Nyanza and Rift valley province. The taro germplasm were planted at Masinde Muliro University of Science and Published: 20 February, 2015 Technology main campus farm field station at Kakamega county (00O 17.30’ and 34o45’East GPS receiver) in western province of Kenya. The phenotypic characterization was based on the International Plant Genetic Citation Resources Institute's (IPGRI) descriptors for Colocasia esculenta. The data Akwee PE, Netondo G, Palapala VA. 2015. Comparative was collected from both qualitative and quantitative traits. The phenotypic analysis of phenotypic characterization of Kenya and characteristics were classified into leaf and petiole characteristics. From Pacific Islands tarogen germplasm collections Colocasia the research study, the phenotype characters such as plant height, presence esculenta L. (Schott). Scientia Agriculturae, 9 (2), 113-119. or absence of stolons, number of sucker holds the highest criteria to be Retrieved from www.pscipub.com (DOI: selected towards improving the taro crop. These phenotypic characters are 10.15192/PSCP.SA.2015.9.2.113119) vital diagnostic features for distinguishing taro genotypes and they may serve as genetic bench markers that could facilitate selection of suitable germplasm variety for crop improvement in the country. Comparative assessment on the phenotypic characterization of the germplasm is a key guide to search for desirable traits that are important in crop productivity and breeding. This could lead to an increased understanding of the adaptation potential of taro in various ecological zones to e

Evaluation of Polymorphism Generated By Single Sequence Repeat Markers in Selected Taro Populations

Genetic structure of Kenya and Secretariat of Pacific Community’s Tarogen taro germplasm was investigated. Fifty cultivars were evaluated using six SSR primer combinations. Significant polymorphic variations within the Kenyan and Tarogen taro sub-populations were revealed. A total of 64 alleles were detected with sizes from 99 to 294 bp. Kenyan germplasm generated 30 alleles and averaged 5.0 alleles/ locus while the Tarogen revealed 34 alleles with an average of 5.70 alleles/ locus. Primers generated a higher polymorphism information content (PIC) in Tarogen (0.6508) compared to Kenyan (0.6108) genotypes and genetic diversity index mean in Tarogen (0.6989) than Kenyan (0.6530) genotypes. Genetic diversity ranged between 0.25 to 0.6218 and 0.25 to 0.06204 for Kenyan and Tarogen genotypes. Allele frequency ranged from 42.52 to 75% across the populations. Generally, observed mean heterozygosity was lower than the expected mean genetic diversity indexes of 0.6530 and 0.6989 for Kenyan and Tarogen. Kenya recorded the highest mean genetic diversity (0.4735) and richness (3.04), allele frequency (0.62) and PIC (0.412) while Tarogen recorded 2.0, 0.4527, 0.5988 and 0.3917, respectively. Observed genetic diversity was significantly greater than the expected diversity. All the evaluated primers displayed distinct polymorphisms among the taro accessions studied indicating the robust nature of microsatellites in revealing polymorphism variability

Genetic diversity analysis of Kenyan taro [Colocasia esculenta (L.) Schott] accessions using SSR markers

Six SSR primer pairs were used to characterize 25 taro genotypes of Kenya. A total of 30 polymorphic alleles were generated. The number of alleles per locus ranged from 1 to 6 alleles, with an average of 3.0425 alleles across 18 loci obtained in the study. The polymorphic information content values ranged from 0.1875 to 0.5731 in all 18 loci with an average of 0.4120. Genetic diversity ranged from 0.25 to 0.6218. Genetic richness ranged between 1.5 and 4.67. The frequency of most common allele at each locus ranged from 51.21% to 75%. The pair wise genetic dissimilarity co-efficient indicated that the highest genetic distance was obtained between the Rift Valley and Nyanza taro germplasm populations (0.794). The closest allele similarity was between Western and Nyanza (83.1%) taro populations while the widest dissimilarity was between Rift Valley and Nyanza populations (45.2%). Being grouped into a distant cluster KK12 could be exploited as probable parental for the development of variant taro varieties. The SSR markers are comprehensive source for the identification of genetically distant taro accessions as well as in the replica sorting of the phenotypically close germplasm

Genetic Structure and Geographical Relationship of Selected Colocasia esculenta [L. Schott] Germplasm Using SSRs

Aims: SSR markers were used to infer population genetic structure variability in taro cultivars with the objective of characterizing the allelic diversity of each geographical population. Place and Duration of Study: Masinde Muliro University of Science and Technology and Beca Hub, ILRI, Nairobi. Methodology: Six highly polymorphic SSR markers widely distributed in taro population genome were used in genotype 50 cultivars collected from Kenya and a taro genebank (SPC Tarogen). Results: The average polymorphic loci was 87.88%. The highest Shannon information index was observed in the germplasm from Nyanza (1.04), Western (1.2) and Hawaii (1.11) and Malaysia (1.36). Only Malaysia and Thailand germplasm had allele unique to a single locus. The analysis of molecular variance (AMOVA) revealed that 70% of the variations found within individual taro accessions, 6% of variations among the taro populations and only 24% amongst individual taro genotypes and they were statistically significant (p<0.001). Principal component analysis clustered the taro germplam into different groups. In total 50.06% and 51.82% of the variation was explained by the first three principal components of the taro germplasm. Some of the Kenyan taro cultivars clustered together with the Tarogen germplasm. Conclusion: The determination of genetic diversity is core function towards understanding taro genetic resources for varietal identification to rationalize its collection and safeguarding the existing genetic diversity for taro germplasm conservation, management and for potential utilization for food security

A critical review of the role of taro Colocasia esculenta L. (Schott) to food security: A comparative analysis of Kenya and Pacific Island taro germplasm

The many threats to global food security in Sub Sahara Africa include poverty, unsustainable cultivation practices and climate change. Increasing poverty and decreasing food security have been exacerbated by continued low food crop productivity by smallholder farmers, constrained by several factors. Taro (Colocasia esculenta L. (Schott.) is a amongst the category of plant species that farmers and researchers have neglected or underutilized crops considered as orphan crops yet they can have the potentials to ameliorate malnutrition and food paucity in developing nations. In Kenya, taro production has suffered low crop productivity leading to underexploitation in terms of popularity of the crop, food security, nutritional aspects and economical contribution to the country earnings. In terms of food production, it does not translate into improved yields for sustained food security and as a result of this; its agricultural production is extremely low. The agronomic potential and importance of taro remains unknown because it has remained as underutilized crop in the country due to little attention attached to the crop. As a result, it has led to dangerous levels of reduced economic livelihoods and loss of its genetic diversity. This paper review interest in neglected taro food crop stems from a variety of factors that could lead to an increased understanding of the adaptation potential of taro to enhance development of efficient and sustainable taro cultivation practices. The review could be a major breakthrough in understanding various biotechnological approaches towards integrating the taro crop into mainstream research for crop improvement and intervention programs. © 201 5 PSCI Publisher All rights reserved. Key words: Taro as a food crop; Under-exploitation; Commercial production; Agronomic potential; Low crop productivity; Undesirable impacts; Economic livelihoods; Genetic diversity; Smallholders farmers

Identification and molecular characterisation of Taro bacilliform virus and Taro bacilliform CH virus from East Africa

Taro (Colocasia esculenta) and tannia (Xanthosoma sp.) are important root crops cultivated mainly by small‐scale farmers in sub‐Saharan Africa and the South Pacific. Viruses are known to be one of the most important constraints to production, with infections resulting in severe yield reduction. In 2014 and 2015, surveys were conducted in Ethiopia, Kenya, Tanzania and Uganda to determine the identity of viruses infecting taro in East Africa. Screening of 392 samples collected from the region using degenerate badnavirus primers revealed an incidence of 58–74% among the four countries surveyed, with sequence analysis identifying both Taro bacilliform virus (TaBV) and Taro bacilliform CH virus (TaBCHV). TaBCHV was identified from all four countries while TaBV was identified in all except Ethiopia. Full‐length sequences from representative TaBV and TaBCHV isolates showed that the genome organization of TaBV isolates from East Africa was consistent with previous reports while TaBCHV isolates from East Africa were found to encode only four ORFs, distinct from a previous report from China. Phylogenetic analysis showed that all East African TaBV isolates form a single subgroup within known TaBV isolates, while TaBCHV isolates form at least two distinct subgroups. To the authors' knowledge, this is the first report describing the occurrence and genome organization of TaBV and TaBCHV isolates from East Africa and the first full‐length sequence of the two viruses from tannia