Morphological characters, yields and active principles in wild and cultivated accessions of the Chilean medicinal plant Buddleja globosa Hope

Buddleja globosa is a medicinal shrub native to Chile. Its leaves have been traditionally used for wound and ulcer healing. Different medicinal properties, such as outstanding antioxidant, anti-inflammatory, wound healing and analgesic activities have been shown. Today, all raw materials for pharmaceutical process are coming from wild collection or recently established crops but not from selected plants. Studies of the genetic or environmental variability of the species would permit the optimization of yield and quality factors through the selection of genetic material or suitable production sites and management techniques.To assess which traits are determined genetically some yield related plant and leaf characteristics were studied in three wild populations and the cultivated accessions from the same provenances. The cultivated accessions also included three clones coming from individuals found in rural home gardens. For the cultivation studies individuals were arranged in a randomised block design, and those for the irrigation studies in split plots watered at 20% and 65% field capacity.Plant characteristics such as height and width of the plant, the ratio of both, stem diameter and leaf density differed significantly among natural populations. In leaf characteristics only the presence of stipules showed significant differences. The cultivated progenies or clones may give an idea if these differences among populations are due to environmental or to genetic effects. Compared with other provenances, plants from the coastal provenance Los Ruiles are tallest in both natural populations and cultivated clones and also showed superior leaf yields in spite of their lower leaf density.The hairy leaves may cause allergic reactions at the moment of harvest. This characteristic is not influenced by different irrigation treatments and shows no significant differences between cultivated and wild plants.Because of the significant higher leaf yields per plant in home garden clones we assume that formerly individuals with a higher leaf production were selected for cultivation.     

Evaluation of micropropagation for the introduction into cultivation and conservation of Lippia junelliana, an endemic aromatic plant from Argentina

The aims of this work were to introduce Lippia junelliana into cultivation, to compare the essential oil accumulation between cultivated and wild plants, and to reintroduce micropropagated plants in the location of the original population. The leaves and inflorescences of cultivated plants accumulated, on a dry weight basis, higher amounts of essential oil than their wild counterparts. Thus, total essential oil accumulation of cultivated plant parts was also significantly higher than that of wild counterparts. The cultivated plants showed the same essential oil profile than the wild plants. This work demonstrates that cultivation can be a more efficient vehicle to both preserve and exploit L. junelliana, than collection from the wild, because higher yields of biomass and oil accumulation can be achieved, while essential oil composition is less affected by the different treatments. The reintroduction of new plants into the species’ original location has proved to be a viable alternative for their in situ preservation or enrichment planting. This model of introduction of aromatic plants into cultivation through micropropagation could be a useful technique to recover valuable chemotypes from the wild in the search for new alternatives in the agriculture and for the preservation of natural resources for future generations.     

Antioxidant and trace element content of damiana (Turnera diffusa Willd) under wild and cultivated conditions in semi-arid zones

Damiana (Turnera diffusa Willd) is traditionally used in the elaboration of tea, liquors, in the production of cosmetic products, and as a medicinal plant. The aim of this study was to evaluate the antioxidant content and trace element concentrations in leaves and stems from damiana grown wild and under cultivated conditions in semi-arid zones. Plants were collected at three different sites, two where damiana grows wild and one where it is cultivated for experimental purposes. Significant differences in the concentration of trace elements, vitamin C and total phenolic compound content, as well as antioxidant enzyme activities, total antioxidant capacity, and lipid peroxidation levels were found between leaves and stems, as well as among sampling sites. Environmental conditions, in combination with genetic factors, apparently affect the trace element concentrations, antioxidant content, and total antioxidant capacity in damiana grown wild. Results suggest that nutrient enrichment, via the addition of fertilizers, contributed to increased antioxidant defenses in the cultivated damiana plants. Furthermore, we suggest that genetic selection, controlled environmental conditions, and specific agrotechnical practices can increase the antioxidant yield in leaves and stems of cultivated damiana.     

Responses to shade and subsequent recovery of soya bean in maize-soya bean relay strip intercropping

In relay intercropping systems, late-planted crops often grow under the shade of the canopy of early-planted tall crops and then transfer to full sunlight after the harvest of the early-planted crops. In order to know the effects of recovery growth of the late-planted soya bean in maize–soya bean relay intercropping, a field experiment was carried out to observe architectural, morphological, physiological and anatomical traits of soya bean plants related to shade and subsequent removal in intercropping before and after maize harvest, respectively. During shade period, soya bean biomass was severely reduced, and stem elongation was stimulated. Typical features of shade grown leaves were found, such as lower LMA (leaf mass per unit area), thinner thickness, higher chlorophyll content, lower chlorophyll a:b ratio. Whole-plant leaf area analysis found that soya bean increased leaf area ratio by adjusting leaf morphology rather than by dry mass allocation. After maize harvest, leaf area and leaf mass increased rapidly, contributing to compensation growth in intercropped soya bean. Meanwhile, physiological and anatomical traits of leaf went back to similar levels as grown in sole cropping. However, stem morphological traits were irreversible after removal of shade. Finally, no difference on seed weight per plant of soya bean was observed between relay intercropping and sole cropping. Based on these findings, we speculated the recovery growth might be the direct determining factor on pod formation in soya bean, and improvement on the capacity of recovery growth could increase yield of relay intercropped soya bean.     

Morphology,accumulation and survival of Desmanthus under different planting densities and harvest heights

The use of legumes is an important strategy for animal feeding, especially during the dry season. The aim was to evaluate the effect of planting densities (40,000; 15,625 and 10,000 plants ha⁻¹) and harvest heights (20 and 40 cm) on the morphology, accumulation and survival of Desmanthus (Desmanthus pernambucanus [L.] Thellung), cultivated in subhumid tropical region, as well as to estimate the repeatability of the evaluated characteristics and the optimal number of measurements. The treatments were randomized in blocks, with subdivided plots and four replicates. Planting densities were evaluated in the plots and the harvest heights in the subplots. Eight harvests were carried out with an interval of 84 days. Morphological and productive characteristics and survival were evaluated. Cultivation under density of 40,000 plants ha⁻¹ produced taller plants, with higher leaf area index (LAI = 0.98), light interception (LI = 49%), individual accumulations (18.8 g DM plant⁻¹) and by area (576.5 kg DM ha⁻¹ harvest⁻¹), although resulting in reduced plant stand (66%). Harvest heights do not affect accumulation and survival. It is possible to reduce the number of measurements for stem diameter, number of leaflets per leaf (R² = 95%), plant height, canopy diameter, LAI, LI, leaf length and width, number of leaves per branch, branch diameter and LBR (R² = 90%), optimizing resources for future research. Desmanthus has potential for use in protein banks, being harvested in the rainy season, conserved and supplied in addition to animals, but plant growth is minimal during the dry season under rainfed conditions.     

株行距和施肥量对木薯产量及生长的影响

采用裂区试验设计方法,研究株行距和施肥量对华南5号木薯产量和生长的影响.结果表明:在本试验株行距和施肥量条件下,施肥量对木薯产量和生长的影响比株行距大.密植(0.6～0.8 m)有利于提高淀粉产量、鲜薯产量和鲜薯淀粉含量,以0.8m株行距最佳,而疏植(1.2～1.4m)有利于提高单株薯数、单株鲜薯重、单株鲜茎叶重、收获指数和茎径.施肥有利于提高淀粉产量、鲜薯产量、单株鲜薯重、单株鲜茎叶重、茎径、株高和单株薯数,但降低鲜薯淀粉含量和收获指数.丰产栽培技术要兼顾单位面积株数、单株鲜薯重和鲜薯淀粉含量.建议在土壤肥力差和少施肥时,用0.6 m株行距;土壤肥力中等且较高施肥时.采用0.8 m株行距;土壤肥力中上且优越水肥管理,采用1.0 m株行距.     

Increasing the content of leaf and root alkaloids of high alkaloid content mutants of periwinkle through nitrogen fertilization

In industrial plants such as medicinal plants, the content of the economically important metabolite is more important than the yield of the plant part containing the metabolite, as it determines the cost of extraction of the metabolite. Two high alkaloid content mutants of periwinkle (Catharanthus roseus, a medicinal plant yielding anti-cancer and anti-hypertension alkaloids) were developed through induced mutagenesis. Since the availability of nitrogen (N) is expected to play an important role in the biosynthesis and accumulation of alkaloids in plants, the effect of N fertilization on the content of alkaloids of two high alkaloid content mutants of periwinkle was studied, in comparison with their parental variety, Nirmal, to determine the possibility of further increasing their alkaloid contents. The three genotypes were evaluated at three levels of N (0, 100 and 150 kg ha⁻¹) fertilization in a split plot experiment, which was repeated over 2 years. N fertilization significantly increased the content of alkaloids both in leaves and roots of all genotypes. Over genotypes, application of 150 kg ha⁻¹ of N resulted in an increase of 42 and 32% in the content of leaf and root alkaloids, respectively. However, the increase was highest in genotypes with the lowest content of leaf or root alkaloids. The high alkaloid mutants grown at 150 kg ha⁻¹of N fertilization exhibited an increase of 87 and 56% in the content of leaf and root alkaloids, respectively, when compared with their parental variety grown without nitrogen fertilization. N fertilization increased leaf and root yields by 170 and 90%, respectively. The increase in contents of leaf and root alkaloids, due to N application, paralleled the increase in leaf and root yields.     

Cultivation of medicinal and aromatic plants for specialty industrial materials

Specialty materials such as essential oils, pharmaceuticals, colorants, dyes, cosmetics and biocides are obtained from plants. Many species of medicinal and aromatic plants (MAPs) are cultivated for such industrial uses, but most are still wild collected. The need for renewable sources of industrial products as well as the need to protect plant biodiversity creates an opportunity for farmers to produce such crops. The production of plants as raw material for fine chemicals is different than cultivation of ornamental or food crops. This review attempts to give an overview of the use of MAPs in various industries, as well as trends in the various markets involved. Economic and regulatory issues relevant for such uses of MAP material are also discussed, with a focus on the situation in the European Union. The aim is to provide information to potential producers to help identify interesting MAPs for cultivation.     

广西阳朔县重点药用植物资源现状的调查与分析

在第四次全国中药资源普查工作中,采用查阅文献、样线和样方相结合的调查方法,对阳朔县药用植物资源的种类、分布及蕴藏量等进行调查和统计分析。结果表明：（1）本次调查和鉴定,阳朔县共有野生和栽培药用植物919种（包括种下单位）,隶属于160科527属;其中野生重点调查药用植物70种,栽培重点调查药用植物6种,国家Ⅰ级保护植物1种,国家II级保护植物7种,广西重点保护植物8种。（2）对样方调查中发现的57种野生重点药用植物的出现频率和蕴藏量进行统计,其中60.00%的物种蕴藏量小于100 t,野生重点中药材总蕴藏量11 610.18 t;66.67%的物种出现频率低。可见,阳朔县药用植物资源丰富,珍稀濒危保护植物种类多,生态环境保护较好;但各物种的出现频率和蕴藏量差异大,很多物种野生资源稀缺,对部分药用植物的保护已刻不容缓;建议把旅游业与中药种植业相结合,保护自然景观与生态环境,确保经济与生态协调发展。     

Differences in leaf yield and indigo precursors production in woad (Isatis tinctoria L.) and Chinese woad (Isatis indigotica Fort.) genotypes

Isatis tinctoria L. (woad) is one of the earliest known sources of indigo in Europe where it was cultivated since the Middle Ages. Isatisindigotica Fort. (Chinese woad), widely distributed in China, had been used from ancient times as indigo-producing plant and medicinal plant. Both species produce indigo precursors indican (indoxyl β-d glucoside) and isatan B (indoxyl ketogluconate) in their leaves. In order to identify new suitable crops for indigo production in Italy, 17 woad lines were studied under field conditions in Central Italy (Pisa, 43°40′N, 10°19′E) from 2001 to 2003. We analyzed the effects of year, genotype, and harvest times together with their reciprocal interactions on leaf yield and indigo precursors production. Woad lines were then compared with seven I. indigotica lines in a field crop experiment set up in 2003. Extraction and quantification of indigo precursors were accomplished by HPLC-ELSD. Isatan B and indican content, as well as equivalent indigo and fresh/dry leaf yield, were compared between species and among genotypes.     

广西大麻种子生产潜力试验初报

为探索籽用大麻高产栽培方案和测试其种子生产潜力。在不同地点设置不同种植密度、施肥用量,分别进行春播和秋播试验,随机排列、三次重复。结果显示春播冬收大麻植株高大,但种子产量较低;秋播大麻植株矮小,但种子产量较高。大麻雌株相对雄株矮而壮,雌雄株数呈一定比例。自然条件下,小区产量与总株数、雌株高、雌株分枝高呈显著正相关。籽用大麻可以考虑秋播冬收,可以引至平原种植,间苗时应拔掉瘦高的植株。要获得种子高产应保证足够苗数。     

Plant growth strategies of Thymus vulgaris L. in response to population density

Thymus vulgaris L., known as common thyme, is a perennial subshrub native to the Mediterranean region. The use of the extracts and herb of thyme plants as antibacterial, antioxidant, natural food preservative and in cosmetic industry has increased the economic importance of this medicinal crop worldwide. Agricultural practices have an influence on growth and yield of thyme plants. Therefore, an experiment was undertaken to determine the effects of three intra-row spacing (15, 30 and 45 cm) and four harvesting times (vegetative, beginning of blooming, full blooming and fruit set) on plant growth and herbage biomass of thyme in 2007 in the research farm of Shoubak University College in the southern part of Jordan. The experiment was a split plot in randomized complete block design with four replicates. Apart from the experiment in 2007, measurements taken on the 15th of November in 2008 were treated as an independent experiment irrespective of harvesting stage. The effects of spacing were not significant for all the parameters measured in 2007. Intra-row spacing in 2008 had significant effects (P < 0.05) on plant height, canopy diameter, herbage fresh and dry weight and number of leaves on long shoots. Its effect on dry weight of shoots, fresh and dry weight of long shoots, number of long shoots, root depth, leaf area and specific leaf area was very significant (P < 0.01). Results of this study indicated that thyme plants grown using 15 cm planting space and harvested at the fruit set stage in 2007 had the highest fresh and dry weight of shoots. The highest dry weight of shoots, herbage fresh and dry weight was also obtained in 2008 in 15 cm spacing. Closer spacing resulted in significantly taller plants that exhibited higher shoot:root ratio and, therefore, plants grown using 15 cm intra-row spacing had a better use of light and accumulated more biomass compared to plants in wider spacing. The differentiation between long shoots and short shoots throughout plant development in 2007 suggests a specialization in carbon gain along different times in the growing season. Swings observed for shoot:root ratio, leaf area and specific leaf area were related to thyme growth. The decrease in specific leaf area between vegetative and full bloom stage indicated that leaves became thicker as part of an adaptive mechanism to the surrounding environment. Information obtained from growth parameters, leaf area and specific leaf area in particular, could be related to essential oil production in leaves of thyme plants.     

Crop loss of pepper plants artificially infected with Xanthomonas campestris pv. vesicatoria in relation to symptom expression

Crop losses in peppers artificially infected with Xanthomonas campestris pv. vesicatoria (XCV) were determined during 3 years of field experiments in three areas of Israel. Direct losses of 23–44% in fruit yield were recorded when severe leaf infection occurred or was induced at an early stage of plant growth. Yield losses and disease index were markedly lower in plants inoculated at later stages and near maturation. Indirect losses in severely infected fields were mainly due to shedding of leaves and exposure of fruits to sun. In this case, up to 95% of the fruits lost their commercial value. In artificially infected symptomless plants with massive endogenous populations of XCV in the leaves, a loss of 24% in yield was measured, compared with plants free from an endogenous pathogen population.     

不同生境的绞股蓝营养器官解剖特征及品质分析

应用显微技术对同一品种不同生境下生长的绞股蓝(Gynostemma pentaphylla)的根、茎、叶、叶柄等营养器官的解剖特征进行比较研究.结果表明:不同生境使绞股蓝营养器官的形态结构和数量特征发生了不同程度的变化,尤其是叶的解剖特征差异更为明显,叶片厚度、栅栏组织厚度、栅/海的比值、主脉直径、主脉维管束的发达程度均为阳生>中生>阴生,而绞股蓝叶面积的大小则是阴生>中生>阳生.此外,3种生境对绞股蓝产量和品质也产生不同程度的影响,阴生绞股蓝较中生和阳生栽培的产量高,品质好,人参皂苷含量高,说明阴生环境有利于植株生长,可生产出高产优质的产品,从而提高经济效益.     

种植密度对旱地玉米植株性状及耗水特性的影响

以紧凑型玉米品种先玉335为试材,在半干旱区研究种植密度对旱地玉米植株性状、产量性状、耗水量和水分利用效率的影响。结果表明,2010年（平水年）玉米拔节期株高在密度间没有差异,抽雄期株高随密度增加显著降低;2011年（丰水年）拔节期和抽雄期株高均随密度增加有明显增加趋势;穗位高随密度增加呈直线增加。平水年产量随密度增加先增加后显著减少,呈抛物线型,收获指数随密度增加呈明显直线下降趋势;丰水年产量随密度增加而增加,当密度增加至7.5万株/hm²时,产量不再显著增加,收获指数随密度增加变化不大。不同密度生育期总耗水量相差不大,平水年密度间总耗水量极差值为4.1 mm;丰水年总耗水量随密度增加呈增加趋势,极差值仅为17.8 mm,播种-拔节期耗水量随密度增加呈明显增加趋势,其变异系数在整个生育期中最大。平水年玉米水分利用效率随密度增加先增加后降低,当种植密度为7.5万株/hm²时达到最大值;丰水年适宜密度为7.5万株/hm²,其水分利用效率为26.7 kg/（hm²·mm）。     

Production of potato minitubers by repeated harvesting: Effects of crop husbandry on yield parameters

Summary Minitubers can be produced in large quantities by repeated harvesting of tubers from in vitro propagated plantlets at 4, 7 and 10 weeks after transplanting to the glasshouse at high plant densities. Yield parameters of minitubers can be manipulated by crop husbandry. By supplying nutrients or using a square plant arrangement, minituber yield increased. Effects on numbers of tubers were cultivar-dependent. Changing plant density from 50 to 800 plants per m² or the minimal diameter of harvested tubers from 5 to 12 mm did not significantly affect tuber yield per m². Higher plant densities resulted in more tubers per m² but fewer tubers per plant. Removing smaller tubers greatly increased the number of small tubers, but did not affect yield and number of tubers in larger grades. Crop husbandry techniques affected minituber yield mainly through their effects on leaf area duration, and the number of minitubers through their effects on growth of tubers to a harvestable size.     

Alleviation of waterlogging damage in winter rape by application of uniconazole: Effects on morphological characteristics,hormones and photosynthesis

Oilseed rape seedlings (Brassica napus L.) treated with uniconazole were transplanted at the five-leaf stage into specially designed experimental containers, and then exposed to waterlogging for 3 weeks. Pre-treatment of rape seedlings with uniconazole significantly increased seedling height, shoot width, number of green leaves and leaf area per plant, and consequently the shoot, root, and total dry weight after waterlogging. Following waterlogging stress, the uniconazole treated plants had a significantly improved growth including plant height, length and width of leaves, number of green leaves, leaf area per plant, and canopy width at the stem elongation stage, and plant height, stem width, and root, shoot and total dry weight at the flowering stage. At harvest, uniconazole treatment increased the number of primary and secondary branches, seeds per pod, and number of effective pods in branches and in terminal raceme after waterlogging treatment. The uniconazole-induced increase in the number of pods per plant and number of seeds per pod were the two yield components responsible for the significantly greater seed and oil yields obtained from the uniconazole plus waterlogging treated plants, over either the control or waterlogged plants. Uniconazole also reduced waterlogging-induced rise in the erucic acid content of the seeds. The modification of GA₃, zeatin, ABA and ethylene levels due to pre-treatment of rape seedlings with uniconazole might have helped to delay the chlorosis and senescence induced by waterlogging. Uniconazole treatment also increased the leaf photosynthetic rates of waterlogged plants, in part, due to the changes in leaf conductance and hormone levels which ultimately affected various physiological processes.     

Shade is conducive to coffee rust as compared to full sun exposure under standardized fruit load conditions

Shade effects on coffee rust are controversial, possibly because shade helps to prevent high fruit loads, which decreases leaf receptivity to the pathogen but, at the same time, might provide a better microclimate for germination and colonization. These two probable antagonistic pathways are combined under natural conditions. In order to clarify their individual effects, we dissociated the two factors by manually homogenising fruit loads under two light exposure situations, under shade and in full sunlight. The trial was set up in Turrialba, Costa Rica at 600 m of elevation, in a coffee plot initially under shade provided by the tree legume Erythrina poeppigiana. The plot was subdivided into two subplots: one was maintained under shade, whereas shade was eliminated in the second subplot. In each subplot, we removed fruiting nodes from 40 coffee plants in order to obtain the following four levels: none, 150, 250, and 500 fruiting nodes per coffee plant. Coffee rust incidence and severity, along with plant growth and defoliation, were assessed on these coffee plants over a period of two years. Air and leaf temperatures, leaf wetness and relative humidity were also monitored. As expected, the intensity of the coffee rust epidemic increased in line with fruit load. We quantified a 28.9% increase in coffee rust incidence and a 129.2% increase in severity on plants with 500 fruiting nodes as compared to plants with no fruits. With the homogenised fruit load, the intensity of the coffee rust epidemic was greater in the shaded subplot, with a 21.5% increase in incidence and a 22.4% increase in severity. Two mechanisms were suggested. Firstly, we highlighted a dilution effect due to host growth which was 25.2% and 37.5% greater in full sunlight when considering new leaves or new leaf area respectively. Secondly, the microclimate was more conducive to coffee rust under shade, with lower intra-day temperature variations, due to lower maxima, and a higher leaf wetness frequency. We concluded that shade has antagonistic effects on coffee rust. Coffee rust is reduced by shade because shade reduces the fruit load. However, with an equivalent number of fruiting nodes, coffee rust incidence and, to a lesser extent, severity were greater under shade. The service provided by shade in controlling coffee rust is necessarily associated with a disservice that consists in reducing yield in the short term.     

Growth, photosynthesis and root reserpine concentrations of two Rauvolfia species in response to a light gradient

Growth and secondary metabolites responses to light environment can be useful measurements to determine favourable habitat conditions for the cultivation and conservation of medicinal plants. We analyzed the growth, photosynthesis and root reserpine concentrations in seedlings of Rauvolfia vomitoria Afzel and Rauvolfia verticillatae (Lour.) Baill, two important medicinal plants yielding anti-hypertension alkaloids, at four different light levels (20%, 52%, 75% and 100% of full sunlight) in a shade house. Across all light intensities, seedlings of R. vomitoria grew faster with higher relative growth rate (RGR) than R. verticillatae, attributed to its higher photosynthetic capacities (light-saturated photosynthetic rate, A_max) and leaf area ratio (LAR). Typical shade-sun morphological responses to increasing light levels included decreased specific leaf area and LAR, whereas RGR and A_max was highest at median light levels for both species. R. vomitoria allocated higher leaf mass fraction and fine-root mass fraction, similar coarse root mass fraction, but lower stem biomass fraction than R. verticillatae. For fine roots, R. vomitoria had greater specific root length and small diameter than R. verticillatae, indicating its higher resource (water and nutrition) capture abilities. Both species had higher nitrogen concentration and lower reserpine concentration in fine roots than those of coarse roots. Neither reserpine concentration nor nitrogen was affected by light intensities. The reserpine concentration in coarse roots of R. vomitoria increased, whereas that of R. verticillatae decreased with increasing irradiance. Although not significantly, reserpine concentrations in coarse roots were positively correlated with A_max and RGR for both species across all light intensities. Shade or photosynthesis inhibition apparently did not increase alkaloid synthesis, which contrasted with the carbon/nutrient balance theory of plant defense. These results suggested that R. vomitoria and R. verticillatae could attain high biomass and yield of reserpine in high-light habitats (with max. in 75% sunlight), and intermediate-light habitats (with max. in 25–52% sunlight), respectively.     

Optimization of harvest regime and post-harvest handling in geranium production to maximize essential oil yield in Rwanda

In Rwanda, the production of geranium (Pelargonium sp.) essential oil is becoming an important commercial crop for income generation. The understanding of postharvest handling of the crop prior to distillation is a key strategy to maximize oil yields. Two experiments were conducted in commercial fields of rose geranium, Pelargonium graveolens, in Kiyombe (Rwanda) to investigate the effects of (i) the length of dry-down or partial wilt and (ii) the time of day on the quantity and quality of essential oil yield and composition. In the first study, the plant material was harvested at 12:00 noon, and while drying also under the same shade conditions the material was sub-sampled immediately and again at 3 h intervals up through 46-h after harvesting. In the second study, the geranium plants were manually harvested at 10:00 AM, 12:00 noon, 2:00 PM, and 4:00 PM and dried under shade for 17 h prior to steam distillation. The geranium plants harvested in the early afternoon (2:00 PM) had the highest essential oil concentration (0.22%). The chemical profile of the essential oil showed that Kiyombe geranium oil exhibited a suitable chemical composition (citronellol 26.4%, linalool 2.3% and geraniol 13.9%), acceptable for international markets.