Browsing by Author "Isutsa, D. K. 1,2"

Now showing 1 - 5 of 5

Fluorescent SSR Markers and Capillary Electrophoresis Reveal Significant Genetic Diversity in Naturalized Pumpkin Accessions in Kenya
(2017) Kiramana, J. K. 1; Isutsa, D. K. 1,2; Nyende, A. B. 3
This study was undertaken as a preliminary step in determining genetic diversity of naturalized pumpkins in Kenya. It entailed allelic patterns, frequency, inbreeding coefficient, molecular variance, cluster and inter-population genetic analyses. It utilized 96 pumpkin accessions and five fluorescent SSR markers in capillary electrophoresis. Data were captured using ABI 3730 software, and analyzed using GeneMapper V 4.1 software. Measures of genetic variability were determined using GenAlEx 6.5, genetic diversity within and among accessions using Power Marker V 3.25 and data contained in the electrophenograms by GeneMapper V 4.1 software. XLstat 2014 was used for cluster and GenAlEx 6.5 software for principal coordinates analyses. DNA quantity ranged from 62.7 to 2992 ng/µl and quality from 0.56 to 2.1 of 260/280 absorbance ratio. Fluorescent SSR markers detected 23 alleles with an average of 4.6 alleles per marker, with size ranging from 181 to 326 bp. A total of 934 distinct DNA fragments were identified. Mean PIC was 0.49, observed heterozygosity 0.5048, genotype number 6.8, gene diversity 0.5491, and polymorphism 98.5% across the markers. Mean allelic patterns showed great variation among the accessions. Cluster and principal coordinate analysis revealed distinct accession groups independent of their geographic origin. AMOVA indicated that genetic differentiation was significant (P=0.02). Total molecular diversity of 3% was attributed to regional differences, 9% to accession differences within regions, while 88% to differences within accessions. The FST of 0.026 indicated very little genetic differentiation due to continuous selection of pumpkin seeds by farmers. The present study proved that fluorescent SSR markers and capillary electrophoresis are effective in estimating genetic diversity and detecting polymorphisms present in pumpkin accessions in Kenya. The genetic diversity should be related with desirable quantitative and qualitative traits and used in improving pumpkin into commercial cultivars. The KK-3 and KK-56 accessions with unique, private and locally common alleles should be prioritised during conservation efforts.
Food and income provision influence production of pumpkins in Kakamega and Nyeri in Kenya
(2018) Kiramana, J. K. 1; Isutsa, D. K. 1,2; ; ;
Pumpkin is an emerging important fruit-vegetable, although its potential remains unexploited in Kenya. This study aimed at enhancing conservation, preservation and production of naturalized pumpkins through characterisation of accessions and documentation of indigenous traditional knowledge influencing cultivation and utilization. An expedition in 2012 led to collection of 155 accessions belonging to Cucurbita moschata (Lam.) Poir.), with 70 from Kakamega and 85 from Nyeri. The variegated accessions were significantly (P 0.05) the most popular and highly utilized, compared to the exotic green-leafed ones. Significantly (P 0.05) more green-leafed accessions were collected in Nyeri, and variegated in Kakamega. They had significant (P 0.05) fruit shape and skin colour variation. Fruit-form ranged from ovate to globose or elliptical, and the predominant skin colour was dark to pale-green. Intercropping was significantly (P 0.05) the main cropping system. Food provision and income generation significantly (P < 0.05) influenced consumption and cultivation of the pumpkins. Most variegated accessions were inherited from past generations and have become naturalized. The green-leafed accessions were introduced by farmers and other stakeholders. Fruits and leaves were significantly (P< 0.05) utilized by farmers, compared to seeds and whole plants. The quality of fruits and leaves, cooking method and recipes were significantly (P< 0.05) considered by farmers when selecting accessions to cultivate. These factors were significant (P>0.05) in sustaining genetic diversity and conservation. Interventions to preserve positive factors and overcome constraining ones should be promoted to enhance growing of naturalised pumpkin for health creation and income generation.
Genetic diversity of pumpkin accessions in Kenya revealed using morphological characters, diversity index, CATPCA and factor analysis
(2018-02) Kiramana, J. K. 1; Isutsa, D. K. 1,2; ; ;
Pumpkin is one of the most morphologically variable genera in the entire plant kingdom. In Kenya, its genetic diversity is undocumented and distribution is haphazard. An expedition was done in Kakamega and Nyeri regions in 2012 using purposive sampling and IPGRI descriptors that led to collection of 155 accessions planted and replicated three times in the Chuka University experimentation farm. The character ranges were green to orange for mature fruit rind, speckled to striped secondary fruit rind, smooth to warty fruit surface, and white to yellow internal flesh, and yellow to pink-red inner flesh and outer flesh. Sex type was monoecious, with most flowers being male and flowering early; only 9 accessions had female flowers appearing early. Most accessions had globular fruits and second fruit cycle. All the accessions had fruit vein tracks and peduncles that abscised when overripe. Deep fruit ribbing was in 40, while small blossom scars were in 69 accessions. Shannon diversity index based on qualitative traits ranged 0.49 to 1.79, with average of 0.97. Fruit shape and seed coat surface displayed high and low indices, respectively. Nyeri accessions had the highest diversity index. CATPCA, factor and cluster analysis determined relationships of the accessions based on the dissimilarity of qualitative characters. CATPCA and factor analysis reduced the dimensionality of the characters to 13 PCs and factors, respectively. CATPCA captured 78.3% and factor analysis 72.1% of the total variation. The two methods jointly identified second fruiting cycle, central leaf lobes, leaf pubescence type, leaf glossiness, and plant growth habit, leaf and flower colour contributing most to divergence of the accessions. The communalities were mostly high except for few characters exhibiting high specificity. Configuration by scatter Bi-plot along the first two PC axes grouped 124 accessions into variegated and green-leafed. Cluster analysis identified four groups with 59, 40, 24 and 1 accessions in clusters one, two, three and four, respectively. The green-leafed accessions were grouped in cluster three and four, and the variegated into cluster one and two. The characters with high discrimination can be useful in identifying variation that can be used for direct selection and in assisting breeders in the identification of pumpkin germplasm with desirable traits for inclusion in breeding and improvement programmes.
Nutritive Value of Bakery Products From Wheat and Pumpkin Composite Flour
(2017) Kiharason, J. W. 1; Isutsa, D. K. 1,2; Ngonda, P. N. 2
The pumpkin fruit of the species C. moschata Duchesne has great nutritional potential, but remains under-utilized in Kenya. The fruits have diverse health enhancing properties. This vegetable-fruit has potential to be processed into various products both for home and industrial use. Despite these benefits, the fruit is underutilized as characterized by the few available pumpkin fruit flour products’ recipes and little contribution to food security in Kenyan households. The present study determined sensory acceptability of baked products of blended pumpkin and wheat composite flour. Uniform mature pumpkin fruits grown on the Chuka University farm were harvested and processed into flour using a previously developed protocol. Pumpkin flour was augmented at 0%, 5%, 20%, 50% and 95% into wheat flour and baked to make cake, bread, mandazi, scones and cookies. The products were then subjected to sensory acceptability tests using a 5-scale hedonic rating, with 1 being least preferred and 5 most preferred by trained and untrained panelists at KALRO-Njoro and consumer groups in Nyeri County, Kenya. The ANOVA showed that products significantly (P<0.05) differed in acceptability. Among Nyeri consumers, 50% cake and 5% mandazi and scone formulations were highly preferred for colour, texture and flavour. In Njoro, there were significant differences (P<0.05) among the trained and untrained panelists, but overall in all products, the 0% and 5% formulations scored highest across all test parameters. Value addition and commercial utilization of any food product greatly increases demand. This study shows the great potential of value-added pumpkin flour in enhancing and enriching textural and sensory qualities of different commercial food products in the Kenyan food industry, which should be promoted for adoption and commercialization.
Participatory Germplasm Conservation and Seed Production of Naturalized Pumpkin Landraces in Kenya
(2016) Kirimi, J. K. 1; Isutsa, D. K. 1,2; Nyende, A. B. 3
Although seeds come first in the food chain, local and international companies find it unprofitable to invest in provision of African indigenous vegetable seeds to growers. The present study trained farmers in on-farm multiplication of seeds for preferred local pumpkin landraces previously collected from Kakamega and Nyeri counties in Kenya. Nine naturalized accessions of Cucurbita moschata (Lam.) Poir were selected for use based on their earlier superior performance in evaluation trials. They were planted at 2 m x 2m in a completely randomized design, replicated three times in Butere- Mumias, and managed by farmers in Shinyalu and Othaya. Qualitative and quantitative data were collected and subjected to Chi-square and variance analyses, respectively. The three sites significantly (P0.05) different. The farmers trained in three years were 132 in Kakamega and 82 in Nyeri. The present study has found sufficient seed yield variation in naturalized pumpkin accessions in Kenya that could be exploited. Consequently, KK-30, KK-35, KK-40 and KK-45 are recommended for adoption and development into commercial pumpkin seed and fruit production cultivars. Regional farmers should be mobilized and empowered to commercially produce and conserve the preferred, but endangered pumpkin produce and germplasm.