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2023 Volume 3
Article Contents
Abstract
Introduction
Perennial grasses as natural allies of soil health
Perennial grasses as natural allies of soil biodiversity
Perennial grasses in climate change mitigation
Perennial grasses in combating invasive plants
Conclusions
Author contributions
Data availability
Acknowledgments
Conflict of interest
Rights and permissions
References
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ARTICLE   Open Access    

Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts

  • 1.

    Sierra Leone Agricultural Research Institute (SLARI), IDA, Kenema 42215, Sierra Leone

  • 2.

    Department of Genetics and Biotechnology Faculty of Biological Sciences, University of Calabar, PMB 1115 Calabar, Cross River State 540271, Nigeria

  • 3.

    Department of Crops Science, Faculty of Agriculture, Njala University, Mokonde 42215, Sierra Leone

  • 4.

    Sierra Leone Agricultural Research Institute (SLARI), Tower Hill, Freetown 42215, Sierra Leone

More Information
  • Coffee is a major cash and export crop in Sierra Leone and is mainly cultivated in southern and eastern provinces. Kenema, Kailahun, Moyamba, Bo, Pujehun and Kono are major coffee growing districts in the country. This study looks at the extent of phenotypic diversity of the rare and wild Coffea stenophylla in Kenema and Moyamba districts. The Shannon-Weaver diversity index (H') revealed variations among the samples for the observed 13 morphological traits which ranges from 0 for both fruit colour and calyx limb persistence to 0.87 for angle of insertion of primary branches on the main stem. Among the 13 morphological traits assessed, angle of insertion of primary branches on main stem (0.87), growth habit (0.78), bean size (0.75), young leaf colour (0.66), stem habit (0.66) and fruit shape (0.65) exhibited high level of diversity while seed shape (0.58), stipule shape (0.46), leaf shape (0.43), seed uniformity (0.31) and leaf apex shape (0.06) showed low levels of diversity. This is the first report of phenotypic diversity of C. stenophylla in Sierra Leone and the study thus unraveled existence of diversity among samples. It is recommended that these observed variabilities be exploited in order to develop better accessions that are high yielding yet maintain the same taste. Additionally, genetic fingerprinting needs to be applied to provide a complementary assessment of the observed phenotypic diversity.

  • Introduction

    Perennial grasses [e.g., switchgrass (Panicum virgatum), big bluestem (Andropogon gerardii), indiangrass (Sorghastrum nutans), little bluestem (Schizachyrium scoparium), Maasai love grass (Eragrostis superba), and bush ryegrass (Enteropogon macrostachyus)] are plant species that live for more than two years with deep root systems and the capacity to grow in a variety of climates[1−5]. Although often overlooked, perennial grasses serve an important role in ecosystems, particularly in maintaining soil health and biodiversity, climate change mitigation, and combating alien invasive plants (AIPs)[1,4]. Thus, they are simply natural allies for soil biodiversity conservation, invasive plant management, and climate change mitigation[6,7]. The deep root systems of perennial grasses help soil structure by improving aeration, increasing water infiltration, and lowering soil erosion[1,5]. Also, their extensive root network supports the stability of the soil, making it less susceptible to degradation and encouraging a healthier ecology overall[1,8]. Further, they play a key role in the nutrient cycle by maximizing nutrient utilization and minimizing leaching[9,10]. In addition, perennial grasses contribute organic matter to the soil through biomass, which decomposes over time and enriches the soil with critical nutrients[11−13]. This process improves soil fertility, increasing productivity for other plant species, and agricultural activities[9,12].

    IAPs, also known as non–native or exotic species, are plants introduced to an ecosystem where they do not naturally occur[14−16] and pose a severe ecological, economic, and social impacts[17,18]. Unlike native species, IAPs often lack natural enemies and diseases in their new environments, allowing them to proliferate unrestrictedly[19,20]. Their invasions lead to the displacement of native flora as they outcompete native species for resources i.e., light, water, and nutrients[21,22]. As a result, causing a reduction in biodiversity and the alteration of ecosystem functions, often forming dense monocultures that hinder the growth of other plants and disrupt habitats for native wildlife[23,24]. Moreover, IAPs can alter soil chemistry and hydrology thereby negatively impacting soil biodiversity[6,7,15,25]. IAPs can further impact human health by increasing allergens and providing a habitat for disease vectors[15]. Efforts to manage IAPs typically involve early detection, prevention, and rapid response, such as biological control, mechanical removal, and herbicide treatment[19,25,26]. Although the role of perennial grasses in combating IAPs has been seldom investigated, available studies show that effective management requires integrated eco-friendly management incorporating competitive native perennial grasses to suppress IAPs[6,8,15,27].

    Furthermore, perennial grasses are ecologically significant because they enhance species diversity and soil biodiversity i.e., living forms found in soil, which includes microorganisms (bacteria and fungi), mesofauna (nematodes and mites), and macrofauna, i.e., earthworms and insects[28−32]. This diversity is critical to ecosystem function and plays an important role in nutrient cycling, soil structure maintenance, and plant growth promotion[29,30]. They contribute to nutrient-cycling activities by breaking down organic materials into simpler compounds that perennial grasses and other plants can consume, decomposing dead plants and animals, and releasing nutrients back into the soil, thus increasing soil fertility[32−34]. Further, perennial grasses also promote plant-soil symbiotic relationships such as mycorrhizal associations and rhizobium symbioses, which improves soil health and plant growth[29]. These benefits are enhanced by perennial grasses' root exudates, which support both soil microbial diversity and activity, resulting in a more dynamic and resilient soil environment[1]. However, extreme weather events, such as floods and droughts, as well as IAPs can cause soil organism loss and structural damage, thereby impeding the roles of soil organisms[35−37]. Further, increased temperatures can disrupt microbial activity and nitrogen cycling mechanisms, impacting soil health, and productivity[37,38]. Addressing these challenges needs long-term integrated management approaches that maintain natural ecosystems and increase soil biodiversity, as well as IAP control and climate change mitigation. For instance, promoting the use and maintaining the diversity of perennial grasses in rangelands and agricultural habitats[1,39,40].

    Climate change which is the average change in the earth's temperature and precipitation patterns can also disrupt the delicate balance of soil biodiversity[37,41]. It is driven primarily by human activities i.e., burning fossil fuels, deforestation, and industrial processes which lead to an unprecedented rise in greenhouse gases, such as carbon dioxide and methane in the atmosphere[37,42]. Often the earth's surface temperature increases concomitantly with these greenhouse gasses[41]. Increased temperatures contribute to sea-level rise, more frequent and intense heatwaves, wildfires, and droughts affecting biodiversity, water supply, and human health. Changes in precipitation patterns also lead to extreme weather events i.e., hurricanes, floods, and heavy rainfall, disrupting ecosystems and human societies[37]. It also negatively impacts biodiversity, as species must adapt, migrate, or face extinction due to altered habitats and shifting climate zones[36]. Addressing climate change requires global cooperation and robust policies aimed at reducing greenhouse gas emissions which include the use of eco-friendly approach, for instance, keeping the environment intact with native plants i.e., perennials grasses[43]. Perennial grasses (e.g., turfgrass) are considered potential for mitigating the effects of climate change because they have a high carbon sequestration capacity, storing carbon in both soil and aboveground biomass[44−46]. They can contribute to reducing greenhouse gas levels by absorbing and storing carbon dioxide from the atmosphere in their roots and tissues, thus helping to mitigate climate change[44]. Furthermore, their capacity to minimize greenhouse gas emissions through reduced tillage and increased nitrogen use efficiency makes them an important component of habitat restoration to mitigate climate change impacts[43].

    Consequently, native perennial grasses have been recommended by various previous studies to be used for habitat restoration, including rangelands, because of their physiological and morphological traits, which have shown great potential to improve soil health and biodiversity, mitigate climate change, and combat IAPs[1,5,8,27,40,47]. By their competitive and morphological traits, several perennial native grass species found in African rangelands (e.g., African foxtail grass (Cenchrus ciliaris), horsetail grass (Chloris roxburghiana), rhodes grass (Chloris gayana), E. superba, and E. macrostachyus) and P. virgatum, S. nutans, S. scoparium, and A. gerardii in North America have been tested and recommended for ecological restoration[1−5].

    Perennial grasses as natural allies of soil health

    Preceding studies have demonstrated that perennial grasses have the potential to improve soil health and structure in rangelands and protected habitats[1,48−50]. Unlike annual plants, which have shallow root systems, perennial grasses can penetrate deep into the soil, sometimes reaching depths of several meters as they have deep and extensive root systems[1,7,40]. These deep roots create channels that enhance soil aeration, allowing for better oxygen flow and water infiltration, thereby preventing soil compaction[49]. Perennial grasses contribute to soil stability by binding soil particles together, thereby preventing erosion (Fig. 1), which is important in ecosystems or habitats prone to heavy rainfall or wind[48,49]. This stabilization effect reduces the loss of topsoil, which contains the highest concentration of organic matter and nutrients essential for plant growth[44]. Moreover, perennial grasses have been reported to be efficient in nutrient cycling, a critical process for maintaining soil fertility[49]. For instance, their deep roots access nutrients in deeper soil layers, which might be unavailable to shallow-rooted plants[49,50]. These nutrients are then brought to the surface and incorporated into the plant biomass. When the grasses die back or shed leaves, these nutrients are returned to the soil surface as organic matter, making them accessible to other plants[32,49,51]

    Figure 1.  Diagram illustrating the multifaceted benefits of perennial grasses and their interconnected roles in promoting soil health, biodiversity, IAPs control, climate change mitigation, water retention, erosion control, and habitat provision. The arrows illustrate the complex interactions and synergies among these components, emphasizing the comprehensive ecological contributions of perennial grasses. The central position of perennial grasses highlights their pivotal role in these areas. This visual representation emphasizes how perennial grasses contribute to and enhance various aspects of ecosystem health and stability.
    DownLoad: Full-Size Img PowerPoint

    Furthermore, perennial grasses enhance soil health and structure (Fig. 1), improving the soil's ability to retain water and withstand extreme weather events i.e., heavy rainfall and floods[44,49]. Their extensive root networks stabilize the soil, reducing erosion and runoff (Fig. 1), which are critical for maintaining soil fertility and agricultural productivity under variable climatic conditions[51]. The continuous growth and decay cycle of perennial grasses contributes to the slow but steady release of nutrients[52]. This slow release is beneficial for maintaining a stable nutrient supply, as opposed to the rapid nutrient depletion often seen in soils dominated by annual crops[50]. This process also helps in reducing nutrient leaching, where nutrients are washed away from the soil profile, particularly nitrogen, which is critical for plant growth[49]. Perennial grasses help to reduce N2O emissions; excess nutrients can lead to increased N2O emissions[10,11,53]. They also contribute significantly to the soil organic matter, which is a key component of soil health[52]. Organic matter consists of decomposed plant and animal residues, which improve soil structure, water retention, and nutrient availability[50,52]. The biomass produced by perennial grasses, both above and below ground, adds a substantial amount of organic material to the soil[52]. As the plant material decomposes, it forms humus, a stable form of organic matter that enhances soil structure by increasing its capacity to hold water and nutrients[52,54]. This is particularly important in dry regions e.g. in Africa, where water retention can be a limiting factor for crop growth[49]. The organic matter also provides a habitat and food source for a diverse array of soil organisms, including bacteria, fungi, and earthworms, which further contribute to soil fertility through their biological activities[43,52,54].

    Perennial grasses as natural allies of soil biodiversity

    Perennial grasses play a crucial role in enhancing soil biodiversity (abundance and diversity) and activities within the soil[31,32,51,54]. They provide critical habitats for soil fauna i.e., earthworms, nematodes, and arthropods (Fig. 1)[32,54]. Their complex root systems create a stable environment that supports a wide range of soil organisms[55]. Also, the root systems of perennial grasses exude a variety of organic compounds, including sugars, amino acids, and organic acids, which serve as food sources for soil biodiversity[54]. This continuous supply of root exudates and a stable environment fosters a diverse macro and microbial community, which is essential for maintaining soil health[31,43,54]. For instance, it was reported by Smith et al.[54] that in areas with abundant perennial grasses, a high soil macrofaunal biodiversity (i.e., Lumbricidae, Isopoda, and Staphylinidae) was observed. They further asserted that these grasses were beneficial to soil macrofauna as they increased the abundance and species diversity of staphylinid beetles, woodlice, and earthworms. In addition, Mathieu et al.[56] reported the influence of spatial patterns of perennial grasses on the abundance and diversity of soil macrofauna in Amazonian pastures. These findings suggest that well-managed perennial grasses are vital in enhancing soil macro and microbes in ecosystems[54−56].

    These soil organisms perform various functions, including decomposing organic matter, fixing atmospheric nitrogen, and suppressing soil-borne diseases[29,30,32]. A diverse soil macro and microbial community can enhance nutrient cycling, making nutrients more available to plants[30,56]. Enhanced microbial diversity by perennial grasses contributes to the suppression of pathogens through competition and the production of antimicrobial compounds, thus promoting plant health[32]. They also help in maintaining soil structure, fertility, and overall ecosystem function[32]. For instance, earthworms, often referred to as 'ecosystem engineers', augment soil structure by creating burrows that improve aeration and water infiltration in perennial grass communities[31,51]. Their activity also helps mix organic matter into the soil, promoting nutrient cycling[31,32]. Nematodes and arthropods which feed on perennial grass species contribute to the decomposition process, breaking down organic matter and releasing nutrients that are vital for plant growth[31,54]. The presence of a diverse soil fauna community is indicative of a healthy soil ecosystem, which is more resilient to environmental stresses and disturbances[31].

    Furthermore, perennial grasses are considered as being instrumental in promoting plant-soil symbiotic relationships[43,54], which are crucial for plant health and soil fertility. One of the most well-known symbiotic relationships is between plants and mycorrhizal fungi[29,33]. These fungi colonize plant roots and extend their hyphae into the soil, increasing the root surface area and enhancing the plant's ability to absorb water and nutrients, particularly phosphorus. The relationship between perennial grasses and mycorrhizal fungi is mutually beneficial. The fungi receive carbohydrates produced by the plant through photosynthesis, while the plant gains improved access to soil nutrients and increased resistance to soil-borne pathogens[30]. This symbiotic relationship is particularly important in nutrient-poor soils, where mycorrhizal associations can significantly enhance plant growth and survival. Additionally, perennial grasses promote other beneficial plant-soil interactions, such as those involving nitrogen-fixing bacteria. These bacteria form nodules on the roots of certain perennial grasses, converting atmospheric nitrogen into a form that plants can use[29,30]. This process is essential for maintaining soil fertility, especially in ecosystems where nitrogen is a limiting nutrient.

    Perennial grasses in climate change mitigation

    Perennial grasses are increasingly recognized for their role in climate change mitigation (Fig. 1)[43,44,57]. They can sequester carbon, reduce greenhouse gas emissions, and adaptation to climate variability[58,59]. Their deep root systems and grass-like characteristics make them highly effective in capturing and storing carbon[44]. These roots can penetrate deep into the soil and store carbon for extended periods[59]. Because of this, perennial grasses show potential to enhance the resilience of ecosystems to changing climatic conditions[44]. The roots of perennial grasses are more extensive and persistent compared to annual crops, allowing for greater carbon storage both in the root biomass and the soil[45,46,60]. This process of carbon sequestration involves capturing atmospheric carbon dioxide (CO2) through photosynthesis and storing it in perennial grass tissues (e.g., turfgrasses) and soil organic matter[44−46]. Preceding studies have further shown that perennial grasses can sequester substantial amounts of carbon, contributing to the reduction of atmospheric CO2 levels[45,61]. In addition to carbon sequestration, perennial grasses can reduce greenhouse gas emissions through various mechanisms[43]. One of the primary ways is by reducing the need for frequent soil tillage, which is common in annual cropping systems. Tillage disrupts soil structure, releases stored carbon as CO2, and increases soil erosion[58,61]. Thus, with their long lifespan, perennial grasses can reduce the need for tillage, thereby minimizing CO2 emissions from soil disturbance[43,58].

    Moreover, perennial grasses can improve nitrogen use efficiency, reducing the need for synthetic fertilizers that are a major source of nitrous oxide (N2O) emissions—a potent greenhouse gas[53,62]. Their deep root systems enable them to access nutrients from deeper soil layers, reducing nutrient leaching and the subsequent emissions of N2O[53]. By optimizing nutrient use, perennial grasses contribute to lower greenhouse gas emissions associated with agricultural practices[63]. Also, perennial grasses are crucial for adapting to climate variability[44]. Their deep root systems allow them to access water from deeper soil layers, making them more resilient to drought conditions compared to annual crops[44]. This water use efficiency helps maintain plant growth and productivity even during periods of water scarcity, which are expected to become more frequent with climate change[49]. In general, perennial grasses support soil biodiversity conservation through habitat provision, climate change mitigation, and promoting ecosystem resilience[58]. Besides, these grasses are crucial for ecosystem stability and productivity, particularly in the face of climate change, and ensure the continued provision of ecosystem services (Fig. 1).

    Perennial grasses in combating invasive plants

    Previous studies have shown that IAPs pose significant threats to ecosystems worldwide by displacing native species, altering habitats, and disrupting ecosystem functions and services[15,20,23,64]. Among the integrated management techniques to combat IAPs involves the use of competitive native plants (Fig. 1) such as perennial grasses[6,7,40]. These grasses, which live for more than two years with robust root systems, growth, and resilience to varying environmental conditions, offer several advantages in controlling IAPs[1,48]. Their competitive growth patterns and ability to restore and maintain native plant communities, and establish, and thrive in diverse habitats make them formidable competitors against invasive plants[1]. One of the primary ways perennial grasses combat IAPs is through competition for resources[48]. Their extensive root systems allow them to efficiently absorb water and nutrients, outcompeting IAPs that typically have shallower roots. This competitive edge limits the resources available to IAPs, inhibiting their growth and spread. For instance, species like P. virgatum and big A. gerardii are known for their deep roots, which can reach depths of up to 10 feet (3 m), providing them with a significant advantage over many IAPs[8,48]. They can also outcompete IAPs through their competitive growth patterns including quick establishment and forming dense canopies that shade out AIPs[1,8]. For example, native perennial grasses like S. nutans and S. scoparium have been shown to effectively compete with invasive species i.e., spotted knapweed (Centaurea stoebe) by limiting light availability and space for growth[8,48].

    Moreover, using their extensive root systems that stabilize the soil, perennial grasses can prevent erosion and invasions of IAPs[44]. Invasive plants i.e., carrot weed (Parthenium hysterophorus), cheatgrass (Bromus tectorum), and kudzu (Pueraria montana) can rapidly colonize disturbed soils, leading to severe erosion problems[20,65,66]. However, perennial grasses i.e., P. virgatum and big A. gerardii have been found to reduce erosion and creating an unfavorable environment for IAPs to establish owing to their deep fibrous root systems that hold the soil in place. Perennial grasses can also modify the microenvironment in ways that make it less conducive for IAPs[1,27,66]. They produce dense root mats that strengthen the organic matter content and soil structure, improving the fertility and health of the soil. The diversity and growth of native plant species is aided by improved soil conditions, which further promote biodiversity and inhibit IAPs by strengthening ecosystem resilience[48].

    Additionally, the use of perennial grasses in restoration has shown promising results in reclaiming areas overrun by IAPs and maintaining native plant communities that are disrupted by IAPs[8,66]. By planting a mix of native perennial grasses, land managers can restore ecological balance and prevent the re-establishment of IAPs[26]. These grasses provide long-term ground cover and habitat for wildlife, contributing to the overall health and stability of the ecosystem[1,8,54]. By reintroducing native perennial grasses into areas (e.g., rangelands and protected habitats) dominated by IAPs, ecosystems, and their biodiversity can be restored to their earlier conditions[27,39,67]. For instance, the use of native perennial grasses has been successful in restoring prairie ecosystems that were previously overrun by IAPs i.e., leafy spurge (Euphorbia esula) and purple loosestrife (Lythrum salicaria)[68]. Another important example of using perennial grasses to mitigate IAPs is the restoration of tallgrass prairies in the Midwest United States[8,66]. These prairies were historically dominated by native perennial grasses i.e., S. nutans and S. scoparium, however IAPs i.e., smooth brome (Bromus inermis) and reed canarygrass (Phalaris arundinacea) displaced them, leading to biodiversity loss and altered ecosystem functions[8,66,68]. Studies show that following the restoration of these invaded habitats using perennial grasses, native grasses successfully reestablished and reduced IAPs and promoting native biodiversity[66,67]. In addition, another notable example is the use of perennial grasses to restore riparian areas which were heavily invaded and impacted by IAPs i.e., giant reed (Arundo donax) and saltcedar (Tamarix spp.)[67,69]. Planting native perennial grasses like western wheatgrass (Pascopyrum smithii) and creeping wildrye (Elymus triticoides) in these areas helped to stabilize the soil, reduce erosion, and suppress IAPs, leading to improved riparian habitat quality and ecosystem resilience[18,66,67,69].

    Therefore, competitive suppressive perennial grasses are a crucial tool in the fight against IAPs and other weeds. Their competitive abilities, contributions to soil health, and role in ecosystem restoration makes them invaluable in managing and alleviating the impacts of IAPs. As research continues, the potential for perennial grasses to be integrated into broader IAP strategies remain significant, promising a more sustainable and ecologically sound approach to preserving native biodiversity.

    Conclusions

    Perennial grasses are pivotal in enhancing soil biodiversity, mitigating climate change, and combating IAPs. Their deep root systems stabilize soils, support diverse soil faunal communities, and improve water retention. Besides, they are important grasses in sequestering carbon, reducing greenhouse gas emissions, suppressing IAPs, and supporting the reestablishment of native plant communities. Integrating perennial grasses into protected areas and rangelands management practices could offer a sustainable solution to pressing environmental challenges including invasions of IAPs. Stakeholders i.e., farmers, conservationists, ecologists, and land managers are advised to use perennial grass systems in their restoration practices, crop rotations, and pasturelands to enhance soil health and resilience. They are further commended to use perennial grasses for erosion control and to improve soil structure and fertility. Policymakers could develop and support policies that incentivize the use of perennial grasses in agricultural and restoration projects. Researchers, they are advised to conduct studies to quantify the long-term benefits of perennial grasses on soil biodiversity and climate change mitigation. Additionally, they can develop country or region-specific guidelines for the effective use of perennial grasses in different ecosystems. Hence, by integrating perennial grasses into our environmental stewardship strategies, we can ensure a thriving, balanced ecosystem capable of withstanding the impacts of climate change and IAPs.

    Author contributions

    The author confirms sole responsibility for the following: review conception and design, and manuscript preparation.

    Data availability

    Data sharing not applicable to this article as no datasets were generated or analyzed during the current study.

    Acknowledgments

    The author thanks all the colleagues who reviewed and proofread this article. This work was not supported by any funding agency.

  • The author declares that there is no conflict of interest.

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  • Cite this article

    Lahai PM, Aikpokpodion PO, Lahai MT, Bah MA, Gboku MLG. 2023. Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts. Beverage Plant Research 3:12 doi: 10.48130/BPR-2023-0012
    Lahai PM, Aikpokpodion PO, Lahai MT, Bah MA, Gboku MLG. 2023. Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts. Beverage Plant Research 3:12 doi: 10.48130/BPR-2023-0012
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ARTICLE   Open Access    

Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts

  • 1.

    Sierra Leone Agricultural Research Institute (SLARI), IDA, Kenema 42215, Sierra Leone

  • 2.

    Department of Genetics and Biotechnology Faculty of Biological Sciences, University of Calabar, PMB 1115 Calabar, Cross River State 540271, Nigeria

  • 3.

    Department of Crops Science, Faculty of Agriculture, Njala University, Mokonde 42215, Sierra Leone

  • 4.

    Sierra Leone Agricultural Research Institute (SLARI), Tower Hill, Freetown 42215, Sierra Leone

  • Received: 29 November 2022
  • Revised: 26 April 2023
  • Accepted: 06 May 2023
  • Published online: 29 May 2023
Beverage Plant Research  3,  Article number: 12  (2023)  |  Cite this article

Abstract: Coffee is a major cash and export crop in Sierra Leone and is mainly cultivated in southern and eastern provinces. Kenema, Kailahun, Moyamba, Bo, Pujehun and Kono are major coffee growing districts in the country. This study looks at the extent of phenotypic diversity of the rare and wild Coffea stenophylla in Kenema and Moyamba districts. The Shannon-Weaver diversity index (H') revealed variations among the samples for the observed 13 morphological traits which ranges from 0 for both fruit colour and calyx limb persistence to 0.87 for angle of insertion of primary branches on the main stem. Among the 13 morphological traits assessed, angle of insertion of primary branches on main stem (0.87), growth habit (0.78), bean size (0.75), young leaf colour (0.66), stem habit (0.66) and fruit shape (0.65) exhibited high level of diversity while seed shape (0.58), stipule shape (0.46), leaf shape (0.43), seed uniformity (0.31) and leaf apex shape (0.06) showed low levels of diversity. This is the first report of phenotypic diversity of C. stenophylla in Sierra Leone and the study thus unraveled existence of diversity among samples. It is recommended that these observed variabilities be exploited in order to develop better accessions that are high yielding yet maintain the same taste. Additionally, genetic fingerprinting needs to be applied to provide a complementary assessment of the observed phenotypic diversity.

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    Introduction

    • Botanically, coffee belongs to the family Rubiaceae and the genus Coffea[1]. Initial studies by de Jussieu named the crop as Jasminum arabicanum in 1713 by studying a sample of the tree that originated from the botanical garden of Amsterdam[2]. Unlike some other tree crops, coffee has the advantage of ubiquity and drives a multibillion dollar global coffee industry[3], supports the economy of several tropical countries and by extension provides livelihoods for more than 100 million coffee farmers and their households[4]. On a global scale, Brazil is the world's largest producer of coffee producing 3,558,000 MT (accounting for around one-third of the world's coffee) followed by Vietnam with a production volume of 1,830,000 MT[5].

      The species Coffea has n = 11 as its basic chromosome number, except C. arabica being the only coffee that is polyploid and self-fertile in nature with a chromosome number of 2n = 4x = 44[6]. Other Coffea species such as C. canephora are however diploid (2n = 2x = 22) and self-infertile[6] and need the effort of breeders for commercial production and productivity. As reviewed by Davies et al.[7], the Coffea genus is comprised of 124 species (in cultivation and in the wild). This gives a clear indication that more research needs to be undertaken to develop cultivars that can withstand the test of time particularly amidst changing climate.

      Regardless of breeding overtime, progress on developing climate-resilient coffee is at the initial stages, with attention focused on Arabica (C. arabica) and Robusta (C. canephora)[8,9]. These two species are reportedly said to have a well-defined price difference with Arabica having a higher price in the international market[3] probably due to its superior cup quality. On the other hand, Robusta and Liberica, currently have lower prices serving as alternative sources to Arabica. Like C. stenophylla, C. eugenioides is another minor coffee species believed to have excellent flavour and is gradually gaining popularity as a niche market though the seeds are relatively small[10].

      In Sierra Leone, cultivated coffee varieties are mainly Robusta and Liberica with Robusta dominating the market probably due to its high yielding quality and the only commercially viable variety. C. liberica can only be found in pockets either in Robusta plantations or in abandoned farmlands. As a result of cyclic price volatility and extreme weather conditions, coffee production has several challenges[7] in Sierra Leone leading to near abandonment of plantations with little or no proper maintenance. This commodity together with cocoa serves as a source of livelihood for thousands of smallhold farmers representing 96% of the country’s agricultural export[11]. Furthermore, SLIEPA[11] reported that in 2011, trade figures revealed that 198,000 MT of cocoa and coffee were exported by Sierra Leone, yielding about USD $400 million. This therefore shows that cocoa and coffee have the potential to become major cash and export crops although production and export as well as quality are still far from pre-war levels, prior to the civil war that raged in Sierra Leone for over 10 years. With the rediscovery of the wild C. stenophylla, efforts are being made by the government of Sierra Leone and funding agencies to promote the domestication of this species as it may serve as a niche market for smallhold farmers.

      In terms of climate resilience, C. stenophylla which is endemic to Sierra Leone, Cote D'Ivoire and Guinea stands out amongst the 120 coffee species[12]. Historical references (1834–1929) have indicated that this species has an excellent taste[12] and may be as good as the 'best mocha'[13] and most probably superior to all other discovered coffee species in the world, including C. arabica. However, the age and context have warranted these claims to be caveated and given the fact that sensory praise for this species (universal cupping) has not been undertaken[14]. Additionally, no published sensory information on C. stenophylla has been in existence since the 1920s, probably due to its scarcity in cultivation and rarity in the wild. Ever since its discovery as an edible crop, it has not been in general cultivation since the 1920s[12] and is threatened with extinction in the wild[15] due to agricultural and non-agricultural interventions by humans. Coupled with competition from Robusta coffee whose early progress towards becoming a global commodity coincides with the decline of stenophylla farming[16], poor yield has been given as one of the major reasons why C. stenophylla failed to become established as a major global coffee crop species[16]. Reference to the number of flowers/fruits per node and shoot, C. stenophylla yields are likely to be less than C. arabica and C. canephora, although commercially viable yields are evident[12,14]. For proper management and better exploitation of the available gene pool, knowledge on the pattern and variation for important morpho-agronomic traits is essential[15]. However, phenotypic characterization of the wild C. stenophylla from the hills of Sierra Leone is yet to be undertaken. This study was therefore conducted to assess the extent of genetic variation that exists within collections of wild stenophylla in Sierra Leone. Data were randomly collected on C. stenophylla that were growing in the wild at different locations using the International Plant Genetic Resource Institute (IPGRI)[17] list of descriptors.

    Materials and methods

      Description of the study sites

    • The study was carried out in two key districts (Kenema and Moyamba) in Sierra Leone with notable hills that serve as forest reserves (Fig. 1). Samples from Kenema districts were taken from two communities where C. stenophylla had been discovered in the Kpumbu forest that lies within Latitude 7°59'23.364" N and Longitude –11°11'40.356" W with an altitude of 375 m above sea level and Ngegeru forest which lies within Latitude 7°56'50.634" N and Longitude –11°12'16.818" W with an altitude of 466 m above sea level. Kpumbu and Ngegeru are situated 25 km and 10 km respectively, southwest of Kenema city, the headquarters of the Eastern region. Samples were also taken from the Kasewe hill forest reserve, about 32 km north west of Moyamba town, Southern region to form part of the study site. The Kasewe forest reserve lies within Latitude 8°19'11.694" N and Longitude –12°10'1.62" W with an altitude of 416 m above sea level. The mean annual rainfall of Kambui and Kasewe forest reserves are 2,546 and 2,135 mm respectively, with an average monthly temperature that ranges between 26 and 32 °C from June to October[18]. Both Kasewe and Kambui forests consist of terrain with steep slopes that reach an elevation of between 100–645 m above sea level[19]. Kambui forest has two sections i.e. Kambui north which is about 20,348 ha and Kambui south with land mass of about 880 ha[19]. This study basically focused on Kambui north where the C. stenophylla had been discovered.

      Figure 1. 

      Map of Sierra Leone showing (a) Moyamba and (b) Kenema Districts where C. stenophylla were collected at Kasewe and Kambui hills, respectively.

      The vegetation of these reserves is classified as ever-green with six months of continuous rain fall and a complex biodiversity that spans right across the untouched areas. The vegetation in the reserves have been classified as closed consisting of three vegetation types: Albert logged forest (91.0%), farm bush (7.5%) and vine forest (0.7%) as described by Fayiah et al.[19]. Kambui hill forest serves as protection for more than 12 catchments and eight of these catchments currently supply water by gravity to the Kenema City and its environs[20].

      Experimental materials

    • A total of 203 C. stenophylla genotypes which included 198 accessions collected from the wild from Kenema and Moyamba districts within notable forest reserves and five standard checks that are maintained at ex-situ field gene bank of the Sierra Leone Agricultural Research Institute (SLARI) at Bambawo substation were used for this study. The study was superimposed on wild C. stenophylla at different stages of growth in varying terrain and standard checks planted in 2021 at SLARI research station.

      Experimental design

    • This study was conducted from January to February, 2022 when some seed materials of the wild C. stenophylla were available and the leaves in pretty good shape. Observations were made and samples collected through random selection at each of the aforementioned locations. A total of 173 plants were sampled from the Kambui, while 25 plants were sampled from Kasewe forest reserves and five standard checks at Bambawo substation.

      Data collected

    • Data were collected on 13 morphological traits based on coffee descriptors developed by the IPGRI[17] as shown in Table 1.

      Table 1.  Morphological parameters studied and their description as per the IPGRI[17].

      #Characters and their descriptive values
      1Growth habit: 1 (open), 2 (intermediate), 3 (compact)
      2Stem habit: 1 (stiff), 2 (flexible)
      3Angle of insertion of primaries: 1 (dropping), 2 (horizontal spreading), 3 (semi-erect)
      4Young leaf tip colour:1 (greenish), 2 (green), 3 (brownish), 4 (reddish brown), 5 (bronzy)
      5Leaf shape: 1 (obovate), 2 (ovate), 3 (elliptic), 4 (lanceolate)
      6Leaf apex shape: 1 (round), 2 (obtuse), 3 (acute), 4 (acuminate), 5 (apiculate), 6 (spatulate)
      7Stipule shape: 1 (round), 2 (ovate), 3 (triangular), 4 (deltate), 5 (trapezium)
      8Fruit shape: 1 (round), 2 (obovate), 3 (ovate), 4 (elliptic), 5 (oblong)
      9Fruit colour: 4 (light red), 5 (red), 6 (dark red)
      10Calyx limb persistence: 0 (not persistent), 1 (persistent)
      11Seed shape: 1 (round), 2 (obovate), 3 (ovate), 4 (elliptic), 5 (oblong), 6 (other)
      12Seed uniformity: 1 (uniform), 2 (mixed)
      13Bean size: 1 (small), 2 (medium), 3 (large)

      Data analysis

      Frequency distribution

    • Frequencies of the various 13 morphological traits were computed using Microsoft XL.

      Shannon-Weaver diversity index

    • For each morphological trait assessed, the Shannon-Weaver diversity index (H') was computed using the phenotypic frequencies to assess the overall phenotypic diversity. The number of phenotypic classes used in the Shannon-Weaver Diversity index (H') were normalized by the maximum value (log n) in each case as described by Henninck & Zeven[21] and computed as a measure of the diversity of the traits used. For an 'n' class trait, the observed normalized H' was obtained using the formula:

      H' = –∑ [ (pi) × ln (pi)]

      Where H' = Shannon-Weaver Diversity index,

      Pi = the relative abundance of each trait = n1/N

      ln (pi) = the natural log of relative abundance = ln (n1/N)

      Therefore,

      H' = –∑ [(n1/N) ln (n1/N)]

      Cluster analysis and principal component analysis

    • To further validate the results obtained from frequency distribution and Shannon-Weaver diversity index, the data were transformed and subjected to cluster analysis for the construction of dendrogram and principal component analysis.

    Results and discussion

      Frequency distribution based on morphological traits

    • The use of this descriptor unraveled a broad range of morphological variations among C. stenophylla (Fig. 2). For instance, about 72.0% of the sampled plants had intermediate growth habit while only about 10.0% had compact growth habit. This gives an indication that scanning of the Kambui and Kasewe hills for C. stenophylla requires a great deal of effort if more colonies are to be discovered. Similarly, variations existed in flush colour, fruit shape, seed shape and even in bean size. The existence of these variations may be useful in the development of new lines of C. stenophylla.

      Figure 2. 

      Bar graphs showing (a) growth habit, (b) young leaf colour, (c) fruit shape, (d) seed shape and (e) bean size (seeds were collected from 203 sampled genotypes) of C. stenophylla .

      Growth habit, nature of stem and angle of insertion of primaries on main stem

    • The result shows considerable variation in growth habit of C. stenophylla in the wild with 71.9%; 18.2% and 9.9% of intermediate, open and compact growth habit that span across the study sites. The wild nature of C. stenophylla justifies the presence of all three growth habits probably due to mutations and inbreeding over the years.

      In the same vein, two types of stem nature were observed at all locations with 63.0% of stems being flexible while 37.0% were stiff (Table 2, Fig. 3). This result corroborates the findings of Weldemichael[22] who also reported variations in the growth habit and nature of stem of Ethiopian coffee (C. arabica) accessions. The presence of C. stenophylla with large stem of girth (≥ 20 cm) is an indication that this coffee has been in existence for ages.

      Table 2.  Percentage of phenotypic class values for 13 morphological traits of 203 C. stenophylla

      S/NPhenotypic class%
      1Growth habitCompact9.9
      Open18.2
      Intermediate71.9
      2Stem habitStiff37.0
      Flexible63.0
      3Angle of lateral insertion
      of primaries      		Dropping7.4
      Horizontal spreading59.1
      Semi-erect33.5
      4Young leaf tip colourGreenish11.3
      Green78.8
      Bronzy9.9
      5Leaf shapeObovate0.5
      Ovate3.5
      Elliptic6.9
      Lanceolate89.2
      6Leaf apex shapeAcute99.0
      Acuminate1.0
      7Stipulate shapeOvate3.5
      Triangular87.2
      Deltate9.3
      8Fruit shapeRound7.4
      Oblong78.8
      Elliptic13.8
      9Ripe fruit colourMauve100
      10Calyx limb persistenceNot Persistent100
      11Seed shapeRound9.8
      Elliptic82.8
      Oblong7.4
      12Seed uniformityMixed100
      13Bean sizeSmall7.4
      Medium20.2
      Large72.4

      Figure 3. 

      Stem habit of C. stenophylla showing (a) stiff and (b) soft types.

      Similarly, angle of insertion of primaries of the 203 sampled C. stenophylla showed variations in the following proportions; 59.1%, 33.5% and 7.4% had horizontal spreading, semi-erect and dropping primaries, respectively. The findings of this study on coffee accessions having stiff stem habit is in agreement with the report by Masreshaw[23] although horizontal spreading type of angle of insertion dominates the case of C. stenophylla (Table 2).

      Leaf morphology

    • Based on the IPGRI[17] coffee morphological descriptor, the 203 C. stenophylla from the wild were classified into three key groups with respect to young leaf tip colour (Table 2). The result shows that 78.8% of the young leaf tip colour were green while 11.3% were greenish and 9.9% were bronzy (Table 2, Fig. 4). This result indicates that C. stenophylla exhibit variations in the leaf morphology drawn from different locations.

      Figure 4. 

      Progressive stages of development of C. stenophylla. (a) Match-stick stage i.e. 45 d from date of sowing to germination; (b) Butterfly or two leaf stage i.e. 14 d after germination; (c) 28 d after germination; (d) 35 d after germination; (e) 49 d after germination; (f) 58 d after germination; (g) 63 d after germination; (h) 84 d after germination; and (i) 12 months after germination.

      Unlike C. arabica, where its leaf shape is dominated by elliptic type of shape[22], the leaf shape of C. stenophylla is dominated by lanceolate shape (89.2%). Few of the trees of C. stenophylla had elliptic, ovate and obovate shapes in the following proportions; 6.9%, 3.5% and 0.5% respectively (Fig. 5). From a population of 203 trees, the majority of the trees (99.0%) had acute leaf apex shape while the remaining 1.0% had acuminate tip shape. The findings of this study however do not support the outcome of previous studies[22,24] who reported that the majority of coffee accessions are made up of acuminate type of leaf tip shape. In line with the findings of this study with regards to leaf shape and leaf apex shape, other reasearchers reported the existence of variabilities in leaf morphology of coffee[25,27].

      Figure 5. 

      Leaf shape of Coffea stenophylla showing (a) lanceolate, (b) elliptic, (c) ovate and (d) obovate types.

      Morphological characteristics of C. stenophylla fruit

    • Like other coffee species, the colour of immature C. stenophylla is green. However, the mature or ripe fruit colour of C. stenophylla did not fall within the phenotypic class of light red, red and dark red as stated in the International Plant Genetic Resource Institutes[17] list of coffee descriptors, giving an indication that the C. stenophylla is a rare species of coffee that had not been explored or noticed as at that time. According to the results of this study, the colour of C. stenophylla is mauve (100%) at maturity and becomes blackened when overripe (Table 2). In this reporting period, the distinct mauve colour may be true only for C. stenophylla when it is ripe (Fig. 6). This result contradicts the findings of others[22,24] who found three distinct fruit colour of coffee using the International Plant Genetic Resource Institutes[17] descriptor.

      Figure 6. 

      Seed shapes of Coffea stenophylla showing (a) oblong, (b) elliptic and (c) slightly rounded.

      Based on the results, there were considerable variabilities in terms of fruit shape with 78.8% being oblong, 13.8% being elliptic and 7.4% being type. The present results partly contradict the findings of others[22,23] who had reported lager proportion of roundish fruit shape and red fruit color among coffee accessions collected from Yayu forest of Ethiopia. Unlike the C. arabica whose calyx limb were observed to be persistent[22], the calyx limb of C. stenophylla however, were observed not to be persistent (100%) which is an indication that there is no variability in terms of the persistence of calyx.

      The majority of the seeds of C. stenophylla collected were elliptic (82.8%) in shape while the remaining 9.8% and 7.4%, respectively, were roundish and oblong in shape. Although Weldemichael[22] reported fruit shapes of coffee to be mainly oblong and of two distinct classes, the results of this study proved otherwise with three distinct morphological seed shapes indicating higher variability in seed shape of C. stenophylla.

      Minor variation was observed in the uniformity of coffee seeds with the largest proportion (90.6%) being uniform while a small proportion of it were mixed (9.4%) which is in agreement with others[22−24]. Similarly, the bean size of C. stenophylla were classified into three distinct groups with 72.4% of the beans being large with average length of 13 cm and average width of 8 cm; 20.2% of medium size with average length of 10 cm and average width of 6 cm while 7.4% being of smaller size with average length of 7 cm and average width of 3 cm. This result disagrees with the findings of others[25−27] who reported higher proportion of medium sized coffee beans among C. canephora genotypes indicating that C. stenophylla with such bean sizes and better cup quality is a special and different type of coffee with huge investment potential.

      Shannon-Weaver diversity index

    • The Shannon-Weaver diversity index (H') was used to estimate the phenotypic diversity of the 13 morphological characters and the maximum value was normalized in each case (Table 3). By estimation and interpretation of the results, low (H') (nearer to zero than to one) indicates a low level of diversity and unevenness in the distribution and vice versa[21].

      Table 3.  Estimates of Shannon-Weaver diversity index (H') for 13 morphological traits of 203 C. stenophylla.

      Phenotypic characterShannon-Weaver diversity index (H')
      Growth habit0.78
      Stem habit0.66
      Angle of insertion0.87
      Young leaf colour0.66
      Leaf shape0.43
      Leaf apex shape0.06
      Stipule shape0.46
      Fruit shape0.65
      Fruit colour0
      Calyx limb persistence0
      Seed shape0.58
      Seed Uniformity0.31
      Bean size0.75

      Following the computation of the H', the results clearly indicates large variations among the 203 C. stenophylla samples for the observed 13 morphological traits which ranges from 0 for both fruit colour and calyx limb persistence to 0.87 for angle of insertion of primary branches on the main stem. This result is partly in agreement with that obtained by Weldemichael[22] who reported large variabilities (H' = 1.08) for angle of insertion of primary branches on the main stem of coffee.

      Among the 13 morphological traits assessed, angle of insertion of primary branches on main stem (H' = 0.87), growth habit (H' = 0.78), bean size (H' = 0.75), young leaf colour (H' = 0.66), stem habit (H' = 0.66) and fruit shape (H' = 0.65) exhibited high level of diversity and evenness while seed shape (H' = 0.58), stipulate shape (H' = 0.46), leaf shape (H' = 0.43) and seed uniformity (H' = 0.31) showed medium diversity. Leaf apex shape (H' = 0.06) and calyx limb persistence (H' = 0) showed virtually no diversity (Table 3). Variabilities (high H') have been reported by Yigzaw[28] in C. arabica for nine morphological traits, which partly corroborate with this study in terms of angle of insertion of primaries on main stem, young leaf colour, stem habit and growth habit but low H' for stipule shape, seed uniformity and seed shape. Although Yigzaw[28] reported low variability for bean size, this study found high H' = 0.75 but low H’ for leaf shape and leaf apex shape probably due to varying species, sample sizes and geographical differences. Contrasting results have been obtained for diversity among coffee accessions by some researchers[25]. High level of diversity (H' > 0.5) was reported by Olika[25] for growth habit, stipule shape, branching habit, angle of insertion of primaries, fruit shape and stem habit, but later contradicted the findings by reporting high level of diversity for leaf shape and leaf apex shape, and low level of diversity (H’ < 0.5) for young leaf colour and seed shape. The results obtained by various authors could be attributed to either differences in environmental factors or genetic diversity of coffee species.

      Principal component and cluster analysis of phenotypic diversity of C. stenophylla collected from the wild

    • Improvement of parental lines require the effective and efficient utilization of available germplasm pool and has always served as the prerequisite in coffee breeding programs. Therefore, the phenotypic traits must be correctly assessed and categorized based on either individual or group performance. To further evaluate the phenotypic diversity of the 203 samples of C. stenophylla, the data were subjected to principal component analysis (PCA) and cluster analysis (CA). The average relationship and Euclidean distance were used in the hierarchical cluster analysis for the samples under investigation.

      The unweighted pair group method with arithmetic mean (UPGMA) dendrogram was formed based on the 13 morphological parameters under study. The wild C. stenophylla were clustered into four major groups at 18.13 coefficient level (Fig. 7), which showed morphologically distinct variations among traits. The analysis revealed that cluster I unified two parent subclusters (growth habit and leaf apex shape) while cluster II had one subcluster (stem habit). On the other hand, clusters III and IV each showed three subclusters (angle of lateral insertion of primaries, stipule shape and bean size); (young leaf tip colour, leaf shape and fruit character), respectively.

      Figure 7. 

      Dendrogram of traits of C. stenophylla collected from Kasewe and Kambui forest reserves. GH = Growth Habit, SH = Stem Habit, ALIP = Angle of Lateral Insertion of Primaries, LS = Leaf Shape, YLTC = Young Leaf Tip Colour, LAS = Leaf Apex Shape, STS = Stipule Shape, FS = Fruit Shape, CLP = Calyx Limb Persistence, SS = Seed Shape, SU = Seed Uniformity, BS = Bean Size.

      As a way of validating the cluster analysis, a two-dimensional plot of principal integral component analysis which gives an indication of parental origins of C. stenophylla, was constructed and showed five groups based on the levels of phenotypic diversity. Young leaf tip colour and leaf apex shape emerged as the preferable traits that distinguishes C. stenophylla from other coffee species (Fig. 8). Angle of lateral insertion of primaries, bean size and growth habit were categorized as one group probably due to environmental effects on wild C. stenophylla.

      Figure 8. 

      Two-dimensional plot of principal integral component analysis showing parental origins of C. stenophylla. GH = Growth Habit, SH = Stem Habit, ALIP = Angle of Lateral Insertion of Primaries, LS = Leaf Shape, YLTC = Young Leaf Tip Colour, LAS = Leaf Apex Shape, STS = Stipule Shape, FS = Fruit Shape, CLP = Calyx Limb Persistence, SS = Seed Shape, SU = Seed Uniformity, BS = Bean Size.

    Conclusions

    • This study unraveled the existence of phenotypic diversity among the C. stenophylla from Kpumbu, Ngegeru and Kasewe using 13 morphological characters that were put forward by the International Plant Genetic Resource Institute[17]. This shows that coffee improvement programs for this special type of coffee could result in domestication from the wild, hybridization and selection of high yielding materials. In conclusion, the observed variabilities should be exploited in order to develop hybrids based on the desired traits particularly improvement in the yield of C. stenophylla. It is also essential that the morphological characteristics observed be confirmed through genetic fingerprinting.

      Acknowledgments

      • The authors acknowledge the Director General of the Sierra Leone Agricultural Research Institute (SLARI), the minister and deputy minister of Agriculture and Forestry, Drs. Abubakarr Karim and Theresa Tenneh Dick, respectively for their immense support towards this study. Furthermore, we acknowledge the effort of Dr. Senesie Swaray, Messrs. Momoh Lahai, Alie Sartie, Emmanuel Lasimoh, Titus J. Musa, John Sandy, Lamin Massaquoi and Dauda Mattia who in one way another made this work a success.

      Conflict of interest

      • The authors declare that they have no conflict of interest.

      Rights and permissions
      • Copyright: © 2023 by the author(s). Published by Maximum Academic Press, Fayetteville, GA. This article is an open access article distributed under Creative Commons Attribution License (CC BY 4.0), visit https://creativecommons.org/licenses/by/4.0/.
    Figure (8)  Table (3) References (28)
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    Cite this article
    Lahai PM, Aikpokpodion PO, Lahai MT, Bah MA, Gboku MLG. 2023. Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts. Beverage Plant Research 3:12 doi: 10.48130/BPR-2023-0012
    Lahai PM, Aikpokpodion PO, Lahai MT, Bah MA, Gboku MLG. 2023. Phenotypic diversity of wild Sierra Leonean coffee (Coffea stenophylla) collected from Kenema and Moyamba districts. Beverage Plant Research 3:12 doi: 10.48130/BPR-2023-0012
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  • Introduction
  • Materials and methods

  • Description of the study sites

  • Experimental materials

  • Experimental design

  • Data collected

  • Data analysis

  • Frequency distribution
  • Shannon-Weaver diversity index
  • Cluster analysis and principal component analysis
  • Results and discussion

  • Frequency distribution based on morphological traits

  • Growth habit, nature of stem and angle of insertion of primaries on main stem

  • Leaf morphology

  • Morphological characteristics of C. stenophylla fruit

  • Shannon-Weaver diversity index

  • Principal component and cluster analysis of phenotypic diversity of C. stenophylla collected from the wild

  • Conclusions
  • Acknowledgments
  • Conflict of interest
  • Rights and permissions
  • About this article
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