Thyme is an herb of the Lamiaceae family. The plant is very important in the world of medicinal properties. In order to study morphologic variation among a number of ecotypes of thyme, an experiment was performed based on a randomized complete block design with three replications and 24 treatments at Research Center of Agriculture and Natural Resources of Zanjan. Plant height, length, width, canopy, yield, branch length, leaf length, leaf width, days to first flowering, days to 50% flowering, days between first flowering and 50% flowering dates were recorded. Correlation between the studied agronomic traits was significant. Stepwise regression for plants yield showed that plant length and number of days between first flowering and 50% flowering had a positive effect on yield and plant height. Seed weight had a negative impact on yield. Cluster analysis based on the studied agronomic traits divided the ecotypes into three major clusters. Ecotypes number 1, 3, 5, 7, 9, 11, 15, 17, 20, and 24 located in cluster number 1. Ecotypes number 8, 14, 18 located in cluster number 2 and the rest of the ecotypes were classified in cluster 3.

Background: Thymus is a widely used medicinal plant in food and pharmaceutical industries. Among different species of Thymus, T. vulgaris is used more than other species in therapeutic dosage forms. Objective: This study was conducted to differentiate various Thymus species by TLC fingerprint. Methods: In order to identify and differentiate various species of Thymus, TLC fingerprints of essential oil, dichloromethane, ethylacetate and n-butanol extracts of four available species named  T. vulgaris, T. pubescens, T. citriodorus and T. daenensis were obtained and compared with each other. Results: The results showed that the TLC chromatograms of essential oil and n-butanol extract can not be used as differential identification for the above-mentioned species; while the ethylacetate and dichloromethane extracts are more reliable to be used for TLC fingerprints. TLC chromatogram of ethylacetate extract is specific for identification of T. pubescens and T. vulgaris while T. citriodorus and T. daenensis can be best identified by their TLC fingerprints obtained from dichloromethane extract.Conclusion: For best differentiation of various Thymus species, different extracts of the plants should be used.

Introduction and Objective: Thyme is one of the medicinal plants that is cultivated in some parts of the world and some of its species are native to Iran. The evaluation of the phytochemical diversity of the essential oil of these species is one of the important steps in the breeding of thyme, and such diversity in essential oil compositions is caused by the different effects of environmental and habitat factors. The present research was carried out in order to understand the phytochemical diversity of the essential oil of different populations of thyme. Materials and Methods: In this study, the percentage essential oli compounds in 15 populations (8 populations of T. kotschyanus species, 3 populations of T. migricus, 2 populations of T. fedtschenkoi and a population of T. fallax and T. pubescens) from natural habitats of northwest and west regions of Iran, were studied. In order to evaluate the essential oil percentage and components, flowers of the populations were harvested during flowering season. Identification of essential oil components was performed by gas mass spectrometer (GC/MS) gas chromatography. Results: A total of 27 compounds were observed in the essential oils of the studied populations, and there was considerable diversity among them. According to the results, Thymol, P-cymene, and Gamma-terpinene were the dominant components of the essential oil. The highest essential oli percentage was related to Thymol taht Bukan- Kouhbardzard (69.75%) and Barugh-Takaghaj (62.13%) had the highest amount. The superiority of West-Azarbaijan populations was significant in Thymol components. In addition, Carvacrol was high in Urmia-Qushchi (58.29%), Sardasht (44.77%), and Linalool was high in Saghez (53.21%) population. By principal component analysis (PCA) it was determined that the first three components explained 60% of the variations in the data. Also, the cluster analysis of the populations of West Azerbaijan province and Kurdistan province was divided into two separate groups. Thymol was negatively correlated with 1,8-cineole. Gamma-terpinene, which was one of the other dominant compounds of the essential oil, with 1,8-cineole and Beta. Ocimene compounds showed a negative correlation. The strongest positive correlation between 1,8-cineole with Beta. Ocimene, Caryophyllene oxide with Camphor, and Lavandulyl acetate with Camphene were observed. Alpha-thujen had the highest negative correlation with other essential oil compounds and Carvacrol did not have a high correlation with other compounds. Conclusion: Bukan and Barugh case of high amount of Thymol, and Sardasht, Urmia-Qushchi and Naghadeh populations because of their high levels of Thymol and Carvacrol, are superior and can be useful in pharmaceutical industry, products and breeding programs.

The possibility of using six thyme species (Thymus sepyllum, T. kotschyanus, T. vulgaris, T. daenensis, T. pubescence and T. fedtschenkoi) as a ground cover plant in landscape were evaluated in a two year period. Results showed that in aesthetics point of view during vegetative and reproductive stages, Thymus sepyllum, T. kotschyanus, and T. fedtschenkoi had the highest ranks, while T. pubescence and T. daenensis has got the lowest ranks. Because of early flowering under favorable weather conditions in spring T. kotschyanus had the longest flowering period in comparison to other late flowering species, i. e. T. sepyllum, and T. vulgaris. The highest area coverage, inflorescence number and flower number per inflorescence were also recorded in T. sepyllum and T. kotschyanus. In comparison to other species, T. sepyllum and T. vulgaris had the longest inflorescence, but flower size of these species was smaller than the others, whereas the largest inflorescence diameter and flower size were shown in T. daenensis and T. pubescence. In general, results showed that all studied species have valuable ornamental potential, but T. kotschyanus and T. sepyllum are the most suitable species as a ground cover plant in landscape.

Medicinal plants have been known to act as a harbor for endophytic fungi, owing to their being able to produce bioactive compounds similar to those of their host. Thymus is a member of the Lamiaceae family. It enjoys a long history of traditional and modern medicine as a disinfectant that possesses antimicrobial properties. The pharmaceutical properties of this plant can be attributed to its endophytes. In this research, 89 endophytic fungi of Thymus spp. were tested and examined to investigate their biocontrol effects against the plant pathogenic fungus Botrytis cinerea, the plant pathogenic bacteria Xanthomonas arboricola pv. juglandis and Streptomyces scabies and human pathogens Escherichia coli ATTCC 25922 and Staphylococcus aureus ATCC 33591. Thereafter, to control fungal and bacterial pathogens, the extracellular metabolites of the endophytic fungi were extracted and used in seven different concentrations. The effect of endophytic fungi on the growth of B. cinerea suggested that the M24 isolate (Fusarium subglutinans) was the one with the greatest percentage of inhibition. Out of the 89 isolates tested against bacteria, only one isolate affected X. arboricola, three of them affected E. coli, and eight isolates showed biocontrol effect on bacterium S. aureus. In the case of S. scabies, all Fusarium isolates prevented its growth. Among other isolates, only M32 and M33, which belong to mycelia sterilia, affected the growth of this bacterium. Endophytic extracellular metabolites had great potential to control plant pathogens as well.

Drought stress is one of the most important factors limiting the survival, growth and production of various crops and medicinal plants in the different habitats of Iran. This study was conducted to evaluate the effects of drought stress on seedling growth and physiological traits in four native thyme species as (Thymus kotschyanus, T. dianensis, T. lancifolius and T. pubescens). A factorial experiment was conducted using thyme species as main factor and three levels of water stresses namely well-watered (90% of field capacity), mild (70% FC) and severe drought stress (40% FC) as the second factor based on a Completely Randomized Design (CRD) with 3 replications in 2018, Khorramabad, Iran. Data collected for 14 morpho-physiological traits of the seedlings. The result of analysis of variance showed significant effects of species and water stress levels for all of the traits (p<0. 01). The species by water stress interaction effects were significant for all of the traits except, carbohydrates and peroxidase indicating that the thyme species had different responses to water stress. Results of means comparison between water stress levels showed that the values of root length, root dry weight, root volume and physiological traits, as: leaf electrolyte leakage, carbohydrates, proline content and catalase activity were increased by drought stress and the higher values were observed in 40% FC, indicating that by increasing drought stress both root growth parameters and many physiological traits were significantly increased in all of the species, but, the leaf relative water content (RWC) and leaf pigments decreased. Results of species by water stress showed that the higher values of root length were obtained in T. daenensis and T. lacnifolius in severe stress (40% FC), respectively. However, in the same species, the higher values of roots dry weights were obtained in the mild stress (70% FC), respectively. For physiological traits, the higher values of (RWC), leaf electrolyte leakage, carbohydrates content and leaf pigments were obtained in T. lancifolius, indicating that this species was more tolerated to drought stress than the other species. It was concluded that species of T. daenensis and T. lacnifolius had produced longer roots in the severe drought stress. However, T. daenensis, due to higher areal part production and essential oil yield in the field, was recommended for domestication and cultivation in dryland farming system and semi-stepic rangelands of Iran.

Thyme is one of the most widely used and valuable medicinal plants in the world. To study the genetic diversity, 22 populations of Iranian thyme from four species, T. deanensis, T. Pubescence, T. kotschyanus and T. lancifolius as well as a population of T. vulgaris evaluated by 12 ISSR primers. Ten ISSR primers produced detectable bands with 57 alleles. The highest amount of the PIC (Polymorphism Information Content) was detected in P9 primer with 0. 92 PIC. Primers with AC and AG motifs produced sharper bands. Cluster analysis based on molecular data grouped the populations in two separate classes. The range of genetic distance between populations varied from 0. 03 to 0. 4. Daran-Isfahan population and T. vulgaris revealed the highest (I=0. 43, h= 0. 29) and the lowest (I=0. 16, h= 0. 106) intra-population variation, respectively. The intra-and inter-population diversities contributed 23% and 77% to total Variation, respectively. T. deanensis and T. lancifolius indicated the highest polymorphism with 98. 25% and 77. 44%, respectively while the lowest polymorphism was detected in T. vulgaris (35. 9 %). The intra-and inter-species diversities contributed 10% and 90% to total variation, respectively. Results showed a great genetic variation in Iranian thyme species which could be considered in hybridization and breeding programs.

Introduction Only one-third of the total land area on earth is free of ice and 42% of land experiences temperatures below − 20° C. Plants may or may not establish in extreme cold or hot temperatures, prolonged dry or wet soil conditions. For this reason, there is a growing demand for native plants in the landscape. Factors influencing plant selection include assessments of hardiness and aesthetics, ease of propagation and culture, naturalization potential. There is a high genetic variation in the flora of Iran, about 1810 of 8000 recorded taxons in Iran are native. So there is a great potential for using native plant in regions with harsh climates. The genus Thymus L. belongs to the Lamiaceae family, consist of about 215 species of herbaceous perennials and small shrubs in the world. They originated from Mediterranean region. This genus is presented in Iranian flora by 14 species. Overall, cold acclimation results in protection and stabilization of the integrity of cellular membranes, enhancement of the antioxidative mechanisms, increased intercellular sugar levels as well as accumulation of other cryoprotectants including polyamines that protect the intracellular proteins by inducing the genes encoding molecular chaperones. So, the aim of this study was to assess the freezing stress tolerance of some thyme species as ground covering species in landscaping projects Material and Methods Seeds of Theme species were sown in containers filled with sand, manure, field soil mixture and maintained in glasshouse. Then, the plants transferred to outdoor condition until the late May. At 24 hours before the end of the acclimation period, the plants irrigated and transferred in their containers to a freezing chamber with 3° C for subjection to freezing temperatures (-10,-20 and-30oC). The temperature reduced at the rate of 2° C per h, and after 1 hour at exposure to the freezing temperature, the containers with plants immediately transferred to growth chamber at 4oC for 24 hours to reduce the speed of ice melting and then returned to the glass. Survival rates, proline accumulation, electrolyte leakage, antioxidant enzymes activity were used to evaluate the freezing tolerance of species. For field experiment germinated seeds in container maintained in greenhouse until the environmental conditions were not limiting factor. After that, seedling planted in outdoor condition and subjected to Ardabil city freezing weather in 2 years. In early spring survival rate recorded. Moreover physiological and biochemical and physical responses of species were evaluated in 3 different times (June, December, February). Results and Discussion Results showed that freezing stress adversely affects growth of theme species. There were 100% survival in all species under Ardebil outdoor condition (during two years), but under freezing chamber condition plant treated with-10oC and-30oC showed 100% and 0% survival, respectively. While in-20oC the highest survival rate were shown in T. vulgaris and T. sepyllum, but T. daenensis had the lowest. The lowest values of electrolyte leakage were related to T. sepyllum, T. kotschyanus, and T. vulgaris. The highest chlorophyll and proline content achieved in T. vulgaris and T. kotschyanus, respectively. Peroxidase antioxidant enzyme activity in T. kotschyanus and T. sepyllum were higher than other species. While there were no significant differences among the species in superoxide dismutase and ascorbate peroxidase enzyme activity. According to the results, it can be deduced that T. kotschyanus, T. vulgaris, and T. sepyllum are more frost tolerant than others. However, because of high survival percent in Ardabil climate and under-20oC, all species can be used as frost tolerant ground cover in landscapes. Conclusion According to the results all of the studied thyme species are frost tolerant but T. sepyllum, T. kotschyanus, and T. vulgaris have the ability to withstand the harsh weather condition without a considerable loss in their ornamental potential.

The essential oil of Thymus spp has valuable components such as thymol and carvacrol. The aerial parts of different thymus accessions, cultivated in Shahedied research station of medicinal plants, were collected at flowering stage and then dried in shadow and hydro-distilled for obtaining their essential oils. Analysis and identification of chemical composition of the oil were performed by GC and GC/MS. Among 74 cultivated accessions in 2011, the highest amount of oil yield was related to the accessions CFTNJI (4.17%), ZELP (4%), Q (3.72%), NJICFT (3.71%), XDRMKO (3.54%), respectively and the lowest was related to BHUZSE (0.66%). The highest amount of oil production per hectare was related to the accesstions XDRVGY (87.5 kg/ha), NJICFT (45.42 kg/ha), ZSECFT (40.86 kg/ha), BHUMKO (38.31 kg/ha), respectively and the lowest was related to CFTMKO (0.9 kg/ha). Para-cymene, 1,8-cineol, gamma terpinene, borneol, thymol, carvacrol, geraniol, limonene, acetate geranil, terpineol, linalool, caryophyllene, respectively with values of 28.41%, 31.66%, 20.44%, 29.35%, 71.1%, 81.45%, 76.99%, 43%, 28%, 38.6%, 55.56%, 81%, 20%, were related to the accessions VGYCFT, NJIBHU, MKOMKO, CFTCFT, ZSEQ, NJICFT, CFTQ, MKOQ, CFTZSE, NJIBHU, ZSEQ, NJICFT, CFTQ, MKOQ, CFTZSE, NJIBHU, ZSELP, VGYMKO. In (2012), the highest amount of oil yield was recorded for the accessions Q (4.07%), CFTVGY (3.7%), MKOVGY (3.63%), ZSEQ (3.45%), ZSELP (%3.43), respectively and the lowest was found in VGYMKO (62.0%). The highest amount of oil production per hectare was related to the accessions BHUVGY (74.9 kg/ha), XDRVGY (60.9 kg/ha), XDRLP (51.78 kg/ha), CFT (49.21 kg/ha), Q (46.11 kg/ha), respectively and the lowest was found in BHUZSE (2.36 kg/ha). Generally, in terms of oil yield, oil production and main composition of essential oil, three accessions including NJICFT (Thymus Transcaspicus) with 3.71% essential oil and 45.42 kg per hectare oil production and 81.5 % carvacrol, ZSEQ (T. daenensis) with 3.45% essential oil and 37.15 kg/h oil production and 73% thymol, and XDRVGY (T. vulgaris) with 2.75% essential oil and 78.5 kg/h oil production and 45.8% thymol were selected as superior accessions.