Browsing by Author "Matheri, F."

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Genotyping of Kenyan Passiflora Edulis Flavicarpa Hybrid Accessions and their Parents using SSR Markers
    (Society for Plant Research, 2016) Matheri, F.; Teya, F.; Kioko, F.; Mawia, A.M.; Mwangi, M.; Kirubi, D.T.; Ngugi, M.; Runo, Steven
    The Passion fruit is a significant income earner for Kenya, ranking third after avocado and mango in terms of foreign exchange earnings. Increased research activities targeting variety improvement and development of new varieties have led to development of new passion fruit varieties by KALRO. These varieties are KPF-4, KPF-11 and KPF-12 which are hybrids of natural crosses of the coastal yellow varieties and purple variety. Despite these gains in breeding, there is little information on molecular variability of the hybrids as well as the parents. The present study aimed at evaluating the genetic variation of the hybrid and parent varieties using SSR markers. DNA was extracted using a modified CTAB protocol followed by PCR and analysis done using DARWIN 6 and GenAlex 6.502 software. The resulting dissimilarity matrix showed existing genetic variability among accessions within and among the varieties studied. Further, the results of principal component analysis and phylogenetic tree showed genetic homogeneity within the assigned populations. The findings of this study will supplement the existing body of knowledge in passion fruit breeding.
  • Thumbnail Image
    Item
    In Vitro Anti-Acetylcholinesterase Activity of Dichloromethane Leaf Extracts of Carphalea glaucescens in Chilo partellus Larvae
    (OMICS International, 2016) Njoroge, A.W.; Ngugi, M.P.; Aliyu, U.; Matheri, F.; Gitahi, M.S.; Mwangi, M.B.; Njagi, M.J.; Mworia, J.K.; Ngure, G.M.
    Acetlycholinesterase (AChE) hydrolyses the neurotransmitter acetylcholine resulting in the termination of nerve impulse at the synapse. Anti-acetylcholinesterase activities stop the passage of the nerve impulse at the synapse resulting in continuous stimulation which can lead to death. The manufacturers of many pesticides target the AChE because it interferes with the passage of the nerve impulse. In vitro study revealed that DCM leaf extract of Carphalea glaucescens has anti-acetylcholinesterase activity against crude acetlycholinesterase (AChE) enzyme extracted from Chilo partellus and an IC50 of 12.02 mg/ml was calculated. After qualitative phytochemical screening was carried out the phytochemicals which were present were tannins, phenols, flavonoids, steroids, terpenoids and alkaloids
  • Thumbnail Image
    Item
    Optimising Plant Density and Nitrogen Rates for Effective Powdery Mildew Management in Garden Peas
    (African Crop Science Journal, 2025-05) Muriithi, M.; Mwangi, M.; Karanja, A.; Matheri, F.
    Garden pea (Pisum sativum L.) is crucial in sub-Saharan Africa (SSA), serving both local consumption and export. Its production, however, faces significant challenges mainly due to powdery mildew (Erysiphe pisi), which is responsible for yield losses of up 60%. The objective of this study was to determine the optimum point of N fertiliser interaction with planting densities, for control of powdery mildew disease in garden pea. Treatments included N rates at 0, 15, 30, and 60 kg-1; mode of application (foliar or root base) and plant density(45 cm x 15 cm and 45 cm x 7.5 cm). The treatments were laid out in a randomised complete block design (RCBD), replicated four times. Results showed that disease severity and incidence increased along with N application and plant density; however, yield reduced at both high N rate (60 kg N ha-1) and in the control (0 kg N ha-1) rates. Fertiliser intensity significantly influenced powdery mildew occurrence, pod yield, and plant branches in garden peas, underscoring the need for strategic N management and planting density for sustainable disease management. The study identified 30 kg N ha-1 applied either by foliar or root application, together with 45 cm x 15 cm plant spacing as the most effective combination; which effectively reduced powdery mildew incidence; while improving crop yield
  • Thumbnail Image
    Item
    Phenotyping of Selected Kenyan Passiflora edulis Varieties and Their Hybrids Based on Quantitative Morpho-agronomic Traits
    (OMICS International, 2016) Matheri, F.; Nyamai, D.; Ngugi, M.P.; Runo, Steven; Njuguna, J.K.; Mwangi, M.; Kirubi, D.T.
    The passion fruit was introduced to Kenya through Europe in the 1920s, and only gained significant economic importance in the 1990s. Several species of the genus Passiflora present potential superior characteristics for genetic breeding of the passion fruit germplasm. Quantitative morpho-agronomic traits are important in passion fruit breeding since they allow for discrimination of varieties for important parameters that are useful in selection of fruit for market. The present study aimed at evaluating existing phenotypic variation between the Purple and Brazil varieties as well as their hybrids, developed by the Kenya Agricultural and Livestock Research Organization (KALRO). Seven quantitative morpho-agronomic traits were targeted with replication per plant and variety. Principal component technique and cluster analysis statistical tools of Minitab 17.0 software were used to discriminate the accessions under study based on the morpho-agronomic traits. Both the dendrogram and scatter plot clustered accessions based on their respective varieties, an indication of phenotypic relatedness within varieties. The results of this study will supplement the current body of knowledge on Kenyan passion fruit breeding
  • Thumbnail Image
    Item
    Phytochemical Profile of Prunus africana Stem Bark from Kenya
    (The American Society of Pharmacognosy, 2015) Nyamai, D.W.; Mawia, A.M.; Wambua, F.K.; Njoroge, A.; Matheri, F.; Lagat, R.; Kiambi, J.; Ogola, P.; Arika, W.M.; Cheseto, X.; King’ori, E.; Ramni, J.; Ngugi, M.P.; Muchugi, A.; Ng’ang’a, M.; Burugu, M.W.
    Prunus africana (Hook.f.) is an evergreen tree that grows in African mountains. P. africana species’ bark and bark extracts are used for the treatment of benign prostate hyperplasia. The pharmacological efficacy of the extracts is believed to be due to synergistic effect of several compounds such as phytosterols, pentacyclic triterpenoids and ferulic acid esters. High demand for the bark and bark extracts of P. africana has led to over-exploitation of the natural population resulting to it being listed as an endangered species; Appendix II of CITES. Conservation of the species can be done through domestication. However, growth factors need to be established first to ensure success of on-farm production. With this in mind, the World Agroforestry Centre established a P. africana stand at Muguga, Kenya to evaluate the species phytochemical profile and yields. Phytochemistry profiling was carried out using Liquid Chromatography coupled to Mass Spectrometry (LC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). Myristic acid, linoleic acid, lauric acid, methyl myristate, methyl laurate and methyl linoleate were the major compounds present after analysis of essential oils in the bark samples while campesterol, β-sitosterol, lup-20(29)-en-3-one, palmitic acid, β-sitostenone, (3.β.,5.α)- stigmast-7-en-3-ol, stigmastan-3,5-diene and α-tocopherol were detected in dichloromethane and hexane extracts of the three populations. In methanolic extract we detected cyanidin-O-galactoside, cyanidin-3-O-rutinoside, procyanidin B5, robinetinidol- (4-α-8) catechin-(6,4-α)robinetinol and ursolic acid.. All these compounds have been reported to have salutary benefits in humans. The phytochemical data has important implications in coming up with strategies for sustainable harvesting and conservation of this species as well as its management on-farm.
  • Thumbnail Image
    Item
    Strategies to increase strawberry competitiveness among fruit growers, marketers and consumers in Kenya
    (International Society for Horticultural Science, 2017) Mwangi, M.; Egesa, A.; Matheri, F.
    In Kenya, the perception of strawberry as a high value crop has influenced initiatives to increase production, marketing and consumption. A recent study explored factors influencing competitiveness of strawberry among fruit farmers, marketers and consumers. The study was conducted in four key producing areas in Kenya that are located close to urban markets. Results show that strawberry production is dominated by small-scale growers with majority (>70%) owning less than 1/8 acre, the largest being 3/4 acre. Unlike other short cycle fruit crops where farmers are exiting after 2-3 seasons, strawberry growers are more tenacious, with >50% being in production for over 5 years. Compared to other fruits, berries are more attractive as they can be harvested up to thrice per week, providing more regular income. However, only about 28% of growers have access to refrigerated transport vans or cool boxes required to reduce fruit deterioration. Lack of production skills and cold storage facilities, and comparatively higher perishability of strawberries remain significant disincentives to growers. Among consumers, factors contributing to low strawberry uptake are low awareness (25%), inconsistent fruit quality (20%), high perishability (34%) and comparatively higher cost (20%). Further, knowledge of strawberry nutritional benefits is low among consumers, and there are no public information activities to increase awareness. Averaged across respondents, key competing fruits are banana (23%), mango (16%), apples (13%), water melon (7%), pineapples and passion fruit (6%). Importantly, consumers indicated familiarity and preference for value added strawberry products, e.g., yoghurt (37%), juice (17%), ice cream (12%), and jam. Interventions can emphasize resilience of strawberry, higher return per unit area and input, availing cold chain facilities, increased consumer awareness, and promoting strawberry value added products.