Vol. 18(29), pp. 865-874, September, 2019 DOI: 10.5897/AJB2019.16757 Article Number: 8CF852C61944 ISSN: 1684-5315 Copyright ©2019 Author(s) retain the copyright of this article African Journal of Biotechnology http://www.academicjournals.org/AJB Full Length Research Paper Phenotypic characterization of selected Kenyan Khat (Catha edulis) cultivars based on morphological traits Loise N. Ngari1,2*, Shadrack N. Njagi, James K. Kamau1, Rose C. Lagat1, Amos M. Musyoki1, Beryl O. Akoth2, Festus Kioko1, Zedekiah-A Okwany2 and Mathew P. Ngugi1 1Department of Biochemistry and Biotechnology, Kenyatta University, P. O. Box 43844-00100, Nairobi, Kenya. 2National Museums of Kenya, Nairobi, Kenya. Received 30 January, 2019; Accepted 29 March, 2019 Khat (Catha edulis Vahl) is an evergreen shrub habitually ingested for its euphoric and stimulatory effects. The crop is grown in the Middle East, Somalia, East Africa and Ethiopia. It is referred to as Miraa in Kenya, while in Yemen it has several names like Qat, Kat, Kath, Gat, Chat and Tschat. It belongs to the sub-order Rosidae, family Celastraceae and characterized by astringent taste. Despite the daily use and consumption of khat by millions of people in Kenya, little is known about its phenotypic. Phenotypic characterization is an essential approach for assessment of khat diversity; however, it is limited by morphological plasticity and multiple lineage evolution. The study aimed at evaluating the phenotypic diversity of selected khat cultivars grown in Embu and Meru Counties. Ninety samples from 18 cultivars were collected for phenotypic characterization. MINITAB 17 Software was used for description of principal component and construction of dendrogram using the Euclidean distance tool where 58.7% variability was observed among 13 traits studied in 90 samples of khat. Phenotypes grouped into 2 clusters phenotypic diversity showed considerable variability based on 13 khat traits. This will be useful in breeding and characterization programmes of khat cultivars. Key words: Phenotypic, khat, diversity, cultivar. INTRODUCTION Khat (Catha edulis Vahl) is ever green and an edible and Qaad in Somalia, Muguka and Miraa in Kenya, and plant (Ngari et al., 2018). It is classified in the kingdom Jimma in the Oromo language. In most western Plantae, class Magnoliopsida, order Celastrales, family countries, it is recognized as khat (Ngari et al., 2018). Celastraceae, genus Catha, and species edulis (Sikiru, Khat is said to have originated from Ethiopia and then 2012). The plant was first described a by Swedish botanist spread to East Africa and Yemen (El-Menyar et al., called Peter Forskal. He encountered the plant as he 2015). In Kenya, khat is grown in Meru and Embu travelled to Yemen through Egypt in an expedition that Counties for commercial purposes. In Meru County, it is was paid for by King of Denmark Friederick, who wanted grown around Nyambene hills in Meru North, 320 km all the natural collections (Al Motarreb et al., 2002). North East of Nairobi and the main outlet is Chyulu Maua Countries and communities have different names for the Town (Nyongesa and Onyango, 2010). In Embu county, plant such as Qat and Chat in Yemen and Ethiopia, Jaad khat is mainly found in lowland area of Mbeere region *Corresponding author. E-mail: [email protected]. Tel: +254723544164. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License 866 Afr. J. Biotechnol. which are usually dry (Kiunga et al., 2016). conducted for this crop in Mt. Kenya region where it has Khat also flourishes in arid and semi-arid environments become a major income earner. As a traditional method, where temperatures range from 5 to 35°C with free morphological traits are used to assess genetic draining soil (New Agriculturalist, 2007; Nyongesa and divergence and classify existing germplasm materials. In Onyango, 2010). Khat leaves are harvested in the addition, this technique is easier, cost effective, and easy morning then covered with fresh banana leaves and to score and requires less time and finally it does not polythene bags to maintain freshness (Nyongesa and need any technical knowledge (Malek et al., 2014). Onyango, 2010). Khat is more potent during the dry and sunny season of the year (Ng’ethe, 2012). Harvesting is done throughout the year and planting is spread over a MATERIALS AND METHODS period of time to obtain a continuous supply. Khat is Collection sites usually consumed by chewing the leaves while fresh, although occasionally, leaves are dried, then consumed The germplasm was collected from 12 major khat producing wards as a stimulating juice (Wabe, 2011). (Figures 1 and 2). The wards included: Maua, Kianjai, Gaiti, Mainly, khat chewing is a male habit though it has Kangeta, Muthaara in Meru County and Kaaga South, Kithimu, gained popularity among women (Mwenda et al., 2003; Kaaga North, Mbeti south, Mbeti North, Mavuria, and Muminji in Embu County. Meru County is found in eastern region of Kenya Kiunga et al., 2016). More than 10 million people approximately 225 km northeast of Nairobi, it covers an area of worldwide use khat for psychostimulating effect (Gitonga 6,936 km2. The area receives about 1366 mm per annum. The et al., 2017). In many countries, khat is chewed for social climate of Meru is described as cool and warm with temperature and psychological reasons (Al-Kholani, 2010). Current ranging between 16°C during cold season and 23°C during hot trends indicate that khat is used by all societal groups warm season. Embu County is located approximately at 120 km northeast of Nairobi towards Mt. Kenya. It covers an area of 2,818 regardless of age, gender, affluence, class, education 2 km and lies between latitude 0° 8” and 0° 35” South and longitude and occupation (Gesese, 2013). 37° 40” East. Various khat cultivars are identified based on the communities that consume them. In Yemen, local cultivars of khat are described according to geographical Collection of plant materials location, growth habit and physical appearance (colour of Khat fruits, flowers and fully grown leaves were harvested from the leaf, stem sizes and potency) (Al-Thobhani et al., selected khat plants for morphological characterization. A total of 90 2008). It is documented that different kinds of khat vary in samples were collected from locally available cultivars and three the extent of their pharmacological activity. Farmers in replicates picked randomly from each of the sample giving a total Yemen have four cultivars, namely, Abyadh, Azraq, number of 90 khat samples where different local khat names were Aswad and Ahmar categorized according to the colour of given. shoots and growing twig (Ngari et al., 2018). Also forty For morphological characterization, a small branch of the khat plant was cut aseptically and each packed in between a newspaper kinds of khat cultivar were recognized according to and later transported to National Museums Herbarium Department, geographical origin. In Ethiopia, two major cultivars have where identification and morphological measurements were carried been described as Dimma (red) or Ahde (white). Getahun out. All the information on these plants was recorded based on local and Krikorian, classified khat into three types, namely names given by Meru and Embu communities as well as ‘madness-causing, intoxicating-like spirit and insomnia- geographic distribution (Appendix 1). The local names given by farmers included: Kira Kieru-1, Kira Kieru-2, Kira Kieru-3, Kira Kiiru- causing based on their effects (Al-Thobhani et al., 2008; 1, Kira Kiiru-2, Kira Gitune-1, Kira Gitune-2, Muchuri, Kithara, Ayana and Mekonen, 2004). Little is known of how C. Mutimutiri, Mugiza-1, Mugiza-2, Mugumo-1, Mugumo-2, Mugumo-3, edulis differs morphologically, therefore, in this study the Mugumo-4, Mugumo-5, Muguka-1, Muguka-2, Muguka-3, Muguka- plant was characterized morphologically. 4, Muguka-5, Mugukawakarimi, Gitu,Mutamucii, Mukurukuru, Muruti, Morphological traits have been used for classification of Muceke, Mitune, and Mumbu. variety duplicates, determination of genetic diversity and A total of 13 morphologic traits of 90 khat samples were evaluated according to guidelines provided by Robson (1994). The correlation with characteristics of agronomic significance traits studied were leaf length, leaf width, leaf margin, petiole length, (Zeng, 2015). Morphological characterization of khat inflorescence length, peduncle length, sepal length, petal length, cultivars in Embu and Meru counties was done by and diameter of the stamen, diameter of the filament, ovary length, assessing variations in 13 khat traits. This has been capsule length and the length of the wing (Appendix 2). For each of traditionally used for classification of khat cultivars. It is the khat sample, 3 leaf samples were randomly selected and their clear that most users’ knowledge is limited to only the measurement taken using a digital vernier caliper. Flowers and fruits measurements were taken using wild MSA Switzerland narcotic effects of the plant (Al-Thobhani et al., 2008). dissecting microscope at magnification of ×10. Khat plant cultivars are notable by the level of cathionone (or the narcotic effect of the plant) present in the plant material and also their morphological Data management and statistical analysis differences. The varying morphological features and Raw data was entered into Microsoft excel spreadsheet which was cathionone levels within khat may also be as a result of then imported to Minitab software version 17.0 (State College genetic variations. Morphologic studies have not been Pennsylvania-USA) software. Data was analyzed statistically for the Ngari et al. 867 Figure 1. A map showing Meru County. Source: Survey of Kenya (2011). Figure 2. A map showing Embu County. Source: Survey of Kenya (2011). 868 Afr. J. Biotechnol. differences in means for 13 khat traits, through one-way ANOVA Besides, the mean petiole length did not show significant followed by Tukey’s post hoc test.