Browsing by Author "Kamau, Peter K."

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Agro-Morphological Characterization of Kenyan Slender Leaf (Crotalaria brevidens and C. ochroleuca) Accessions
    (Hindawi, 2020-04) Mwakha, Fridah A.; Gichimu, Bernard M.; Neondo, ohnstone O.; Kamau, Peter K.; Odari, Eddy O.; Muli, Joshua K.; Budambula, Nancy
    Slender leaf (Crotalaria spp) is among the indigenous and underutilized vegetables in Kenya whose production is limited to the Western and Coastal regions of the country. For a long time, this crop has been neglected in terms of research and genetic improvement. *ere is therefore scanty information on its morphological diversity and agronomic performance, hence the need for this study. Field experiments were carried out for two seasons in October to December 2018 and March to May 2019. *e experiments were laid out in Randomized Complete Block Design with 29 accessions and replicated three times. Both qualitative and quantitative data were recorded from the accessions based on the Crotalaria descriptors. Quantitative data were subjected to analysis of variance using XLSTAT Version 2019, and accession means were separated using Student’s Newman Keuls test at 95% level of confidence. Both qualitative and quantitative data were subjected to multivariate cluster analysis, and a dendrogram was constructed using the unweighted pair-group method with arithmetic average. *e principal component analysis was conducted to obtain information on the importance of the characters. Significant variation in agro-morphological traits was found within and between the two species. Cluster analysis grouped the accessions into seven major classes with a between-classes diversity of 75.13% and a within-classes diversity of 24.87%. *is study sets the basis for genetic improvement of slender leaf in Kenya since the observed diversity can be exploited in selection for intraspecific and interspecific hybridization.
  • No Thumbnail Available
    Item
    Genetic diversity and population structure of wild and cultivated Crotalaria species based on genotyping-by-sequencing
    (Plos One, 2022-09) Muli, Joshua K.; Neondo, Johnstone O.; Kamau, Peter K.; Michuki, George N.; Budambula, Nancy L.
    Crotalaria is a plant genus that is found all over the world, with over 700 species of herbs and shrubs. The species are potential alternative food and industrial crops due to their adaptability to different environments. Currently, information on the genetic diversity and population structure of these species is scanty. Genotyping-by-sequencing (GBS) is a costeffective high-throughput technique in diversity evaluation of plant species that have not been fully sequenced. In the current study, de novo GBS was used to characterize 80 Crotalaria accessions from five geographical regions in Kenya. A total of 9820 single nucleotide polymorphism (SNP) markers were obtained after thinning and filtering, which were then used for the analysis of genetic diversity and population structure in Crotalaria. The proportion of SNPs with a minor allele frequency (maf) > = 0.05 was 45.08%, while the GuanineCytosine (GC) content was 0.45, from an average sequence depth of 455,909 reads per base. The transition vs transversion ratio was 1.81 and Heterozygosity (He) ranged between 0.01–0.07 in all the sites and 0.04 to 0.52 in the segregating sites. The mean Tajima’s D value for the population was -0.094, suggesting an excess of rare alleles. The fixation index (Fst) between the different populations based on the Wright Fst (1943) ranged from 0.0119 to 0.066 for the Eastern-Western and Nairobi-Western populations. Model based techniques of population structure analysis including structure, k-means and cross-entropy depicted eight clusters in the study accessions. Non-model based techniques especially DAPC depicted poor population stratification. Correspondence Analysis (CA), Principal coordinate analyses (PCoA) and phylogenetic analysis identified a moderate level of population stratification. Results from this study will help conservationists and breeders understand the genetic diversity of Crotalaria. The study also provides valuable information for genetic improvement of domesticated species.
  • Thumbnail Image
    Item
    Genetic diversity and use of African indigenous vegetables especially slender leaf
    (Taylor and Francis, 2020-10) Muli, Joshua K.; Neondo, Johnstone O.; Kamau, Peter K.; Budambula, Nancy
    African indigenous (AIVs), and traditional, vegetables play a role in food security. This review examines distribution, use, diversity, and techniques used to study AIVs with special interest on Crotalaria species. Google scholar, PubMed, and the open web were searched for published articles between 1990 and 2020. The AIVs are distributed in almost all African countries but are mostly consumed in East and West Africa. The distribution and genetic diversity of some common AIVs has been documented. There is a need to create awareness on the use and conservation of AIVs because of their role in food security and livelihoods.
  • Thumbnail Image
    Item
    A hybridization technique for orphan legumes: development of an artificial interspecific pollination protocol for Crotalaria spp.
    (Taylor and Francis, 2020-08) Wasonga, Mercy A.; Arunga, Ester E.; Neondo, Johnstone O.; Muli, Joshua K.; Kamau, Peter K.; Budambula, Nancy
    rotalaria brevidens: and C. ochroleuca commonly grown as vegetables have been extensively studied. However, information on breeding techniques is scanty. This study aimed to develop an artificial interspecific pollination protocol for two genotypes of Crotalaria with contrasting leaf and pod morphological features. The two are landraces that were previously collected from two counties in Kenya. The experimental design was a completely randomized design (CRD) in a greenhouse with C. ochroleuca as the female parent and C. brevidens as the male parent. Six-day-old flower buds of the female parent were emasculated. Pollen from a freshly opened flower was rubbed over the stigma of the emasculated flower. The pollinated stigma was inserted back into the keel petal and covered by the wing and standard petal. Data on success rate, pod, and seed production were subjected to analysis of variance. The developed artificial pollination method showed 75% success rate in the interspecies cross of C. ochroleuca and C. brevidens. Time of crossing did not significantly influence the success rate, pod, and seed production. The study demonstrated artificial interspecific pollination of Crotalaria by keel petal incision rubbing method. This protocol lays the foundation for genetic studies and improvement of Crotalaria spp.
  • Thumbnail Image
    Item
    Phenomic characterization of Crotalaria germplasm for crop improvement
    (Cabi, 2021-03) Muli, Joshua Kiilu; Neondo, Johnstone O.; Kamau, Peter K.; Odari, Eddy; Budambula, Nancy
    Background: Diversifcation of global food systems through exploration of traditional varieties and wild edible plant species is a focal mitigation strategy for food security worldwide. The present study determined the phenomic diversity of locally available, afordable and climate-resilient cultivated and wild Crotalaria species for breeding purposes. Methods: Seed samples were collected from diferent administrative counties in Kenya spanning diferent climatic zones. Other seeds were provided by the Genetic Resources Research Institute of Kenya. A randomized complete block design with three replications was used for agro-morphological evaluation of the 83 accessions used in this study. Data on quantitative and qualitative traits was collected. Cluster analysis on R and R-studio was used to generate a dendrogram by the Euclidian genetic distance and dissimilarity indices while the non-metric multidimensional scaling (NMDS) method was used to determine the spatial interrelationship between the accessions. The Pearson’s correlation coefcients were used to determine the relationships between qualitative and quantitative traits while the principal component analysis was used to discriminate the accessions. Results: Three edible species (C. brevidens Benth., C. ochroleuca G.Don, C. trichotoma Bojer.) were found to be cultivated by Kenyan farmers and a signifcant variation (p<0.0001) for all parameters under study was recorded. Agglomerative hierarchical clustering grouped the accessions into 8 major clusters. The NMDS ordination formed 15 and 6 groups based on counties and regions respectively. Conclusions: This study forms the basis for exploring novel breeding strategies among cultivated species, between wild and cultivated Crotalaria species as well as determining molecular markers linked to phenomic traits.
  • Thumbnail Image
    Item
    Witchweed’s Suicidal Germination: Can Slenderleaf Help?
    (MDPI, 2020-06) Mwakha, Fridah A.; Budambula, Nancy; Neondo, Johnstone O.; Gichimu, Bernard M.; Odari, Eddy O.; Kamau, Peter K.; Odero, Calvins; Kibet, Willy; Runo, Steven
    The parasitic plant Striga hermonthica (Delile) Benth. is stimulated to germinate by biomolecules (strigolactones) produced in the roots of host and some non-host plants. Non-hosts induce Striga’s suicidal germination and are therefore used as trap crops. Among trap crops, the Slenderleaf legume in the genus Crotalaria (Crotalaria brevidens (L.) Benth.) and (Crotalaria orchroleuca (G.) Don.) has been popularized in African smallholder farms. However, the Striga germination e ciency of these locally grown Crotalaria varieties (landraces) is unknown. Also unclear is Crotolaria’s extent to inhibiting Striga growth, post germination. Extensive parasite penetration can expose the trap crop to secondary infections and possible phytotoxicity from Striga. We used in vitro germination assays to determine the Striga germination e ciency of 29 Crotalaria landraces. Furthermore, we determined Crotalaria’s ability to inhibit Striga attachment and growth using histological analysis. We found that: (i) Crotalaria stimulated germination of Striga seeds at frequencies ranging between 15.5% and 54.5% compared to 74.2% stimulation by the synthetic strigolactone (GR24) used a positive control; (ii) Crotalaria blocked Striga entry at multiple levels and did not allow growth beyond the pericycle, e ectively blocking vascular connection with the non-host. Hence, Crotalaria is suitable as a trap crop in integrated Striga management.