جستجوی مقالات مرتبط با کلیدواژه « accession » در نشریات گروه « کشاورزی »

Soil salinity, as one of the most important environmental stresses, is a serious threat to agricultural production. Currently, more than 20% of the agricultural lands, which includes 954 million hectares of the world's lands, is affected by soil salinity. Salinity is expanding daily and it is predicted that by 2050, more than 50% of the world's arable lands will be saline. The decrease in yield due to salinity stress in wheat is considerable and worrying, so that a 50% decrease in yield of durum wheat due to salinity of rainfed lands, and an 88% decrease in yield of bread wheat under irrigation with high salinity and and a 70% decrease in yield of bread wheat in sodic soils has been reported. The high levels of salt in soils and irrigation waters are worrying factors for agriculture, therefore it is necessary to develop the effective strategies to improve yield through salinity stress tolerance. The present study was carried out due to the importance of genetic accessions as sources of tolerance to biotic and abiotic stresses including salinity, and the existence of considerable genetic diversity in wheat germplasm to salinity stress tolerance. The objective of this experiment is to investigate the diversity of genetic accessions of bread wheat collection of Iran's National Plant Gene Bank, to compare the accessions with the tolerant control varieties, and to identify the new genetic resources for salinity tolerance.

To identify the genetic resources of salinity tolerance in wheat germplasm, 512 accessions from the bread wheat collection of the National Plant Gene Bank of Iran along with salinity tolerant varieties, Kavir, Roshan and Mahoti as controls, were investigated in two different augmented designs under normal and salinity stress conditions. The normal experiment was carried out at the research field of Yazd Research Center and the salt experiment was done at saline lands of Ardekan Research Station. The studied traits included spike length, spike density, 100-grain weight, number of tillers, plant height, number of spikelets per spike, number of florets per spikelet, number of grains per spike, days to heading, days to maturity, grain filling period and grain weight of five spikes,  which were recorded according to the international description. To perform data statistical analyses, descriptive statistical indices were first calculated and then the studied accessions were grouped using K-means cluster analysis. Discriminant function analysis based on principal components was used to investigate the differentiation between the groups resulting from cluster analysis. Statistical analyzes were performed by SPSS and R softwares.
 
 
Research

The results showed that grain weight of five spikes (with a minimum of 4.15 and a maximum of 12.26 g in normal conditions and a minimum of 2.19 and a maximum of 9.78 g in stress conditions) and the number of spikes (with a minimum of 3 and a maximum of 8 in normal conditions and a minimum of 3 and a maximum of 7 in stress conditions) had the highest coefficients of variation, while days to heading (with a minimum-maximum of 130-163 days and 126-168 days in normal and salinity stress conditions, respectively) and days to maturity (with a minimum-maximum of 173-189 days and 168-196 days in normal and salinity stress conditions, respectively) had the lowest coefficient of variation under both normal and salinity stress conditions. A large number of superior accessions were identified for various traits compared to the control cultivars under both normal and salinity stress conditions. The results of stepwise regression indicated the importance of three characteristics, 100-grain weight, number of grains per spike and number of florets per spikelet, in describing the variation of grain weight of five spikes. The investigated accessions were divided into five groups using K-means cluster analysis and the control cultivars were separated into different groups so that Roshan and Mahooti along with 70 accessions were grouped in the first cluster and Kavir along with 53 accessions in the fifth cluster.

The results of this experiment showed the presence of significant and valuable genetic diversity in traits related to salt stress tolerance in the studied bread wheat germplasm. The effect of salinity stress on different traits of the studied accessions was different. Among the studied traits, 100-grain weight, number of grains per spike and number of florets per spike were more important, so they can be used in breeding programs. A large number of accessions were also superior to control cultivars for various traits. Cluster analysis grouped the control cultivars into distinct clusters, which indicates different aspects of salt stress tolerance in these cultivars. The superior accessions identified in this research can be used to improve salt stress tolerance in bread wheat breeding programs.

In order to evaluate root yield and morphological traits of 15 endemic and imported chicory Cichorium intybus L.) accessions and cultivars, an experiment was conducted in a randomized complete block design with five replications in Khoshkedaran Research Station of Mazandaran province, Iran, during 2016-2018 years. In this study, the number of leaves per plant, leaf length and width, plant height, fresh and dry root yield, and some qualitative traits such as root shape and diameter, hairy leaf and stems, bolting time, lignified top root, longevity, and reproductive cycle of chicory accessions were measured. In the first year, the root was not harvested and in the second year, at the end of the rosette stage (rootstock start), the roots were harvested and the relevant measurements were made. Data for each morphological and functional trait were analyzed separately. The results showed that the Selenite cultivar had the highest fresh (35.458 t/ha) and dry (9.574 t/ha) root yield and ranked in the first group of means. The results of principal component analysis (PCA) based on yield and morphological traits showed that the first two components accounted for 72% of the total variation. Based on the results of cluster analysis (Ward method),   the genotypes were classified into four groups. The highest genetic distance was obtained between cluster two (Behshahr accession) and cluster four (foreign cultivars). The results of cluster analysis and PCA were in agreement with each other. According to the results, It was concluded that Tonekabon accession from the first cluster can be cross with the high-yielding cultivar Selenite to breeding improve new varieties of endemic chicory.

Summer savory (Satureja hortensis L.), an aromatic plant from fam. Lamiaceae, is used in the food and pharmaceutical industries due to its compounds such as thymol and carvacrol as antioxidant and antimicrobial compounds. In this research, the diversity of morphological and phytochemical traits between the Iranian and foreign countries accessions of summer savory cultivated under field conditions were evaluated. The seeds of different accessions were planted in a randomized complete blocks design with three replications in Ardabil city in 2019. The studied traits included the number of internodes, shoots, and flowers per plant, days to seed germination, length/width ratio of leaves, crown diameter, dry weight of aerial parts, leaf fresh weight, peduncle length, 1000-seed weight, flower dry weight, days to seed ripening, and content of chlorophylls a and b, carotenoids, and flavonoids. The results of this study showed that the highest number of internodes (10.33) and shoots (24.43), and flower dry weight (3.33 mg) were observed in Khuzestan accession. The highest correlation was observed between the aerial parts dry weight and 1000-seed weight (r= 0.92). Cluster analysis divided the accessions into four major groups. The accessions West Azerbaijan, Qazvin, Tehran, Kurdistan, Lorestan, Razavi Khorasan, and Italy were placed in the first cluster, and Tajikistan, Hungary, Armenia, Romania1, Romania2, Khuzestan, Greece, Russia, Georgia, and North Khorasan in the second one. Also, the accessions Gilan and Yazd were put in the third group and Uzbekistan in the fourth one. Factor analysis indicated that the seven factors could explain 86.59% of the total variance. The results suggested that S. hortensis accessions of Iran and other countries had a high genetic diversity that can be used in the breeding programs. Overall, according to the results, the accessions Uzbekistan and Greece could be recommended in terms of dry matter yield and phytochemical characteristics, respectively.

Summer savory (Satureja hortensis L.) is a valuable medicinal plant with useful properties and applications, has been recently used in the pharmaceutical industry due to its high level of carvacrol, thymol and rosmarinic acid. In this research, different accessions of this plant were collected from other countries and different regions of Iran. An experiment was conducted in 2019 year based on randomized complete block design to evaluate the morphological, phytochemical and essential oil traits of these accessions in Ardabil climatic condition. Analysis of variance showed that there were significant differences for the most studied traits among 20 accessions. The important traits such as plant diameter (19.78-45.29 cm2), shoot dry weight (0.08-2.05 g/p), 100-seed weight (0.021 to 0.126 g/p), and essential oil yields (0.23 to 2.21 g/h) were varied among accessions. The Ahvaz and Greece accession were the best in term of vegetative and phytochemical traits respectively. Maximum correlation was shown between bract number and seed length per plant (0.96). Cluster analysis, classified the accessions into five major groups. Factor analysis indicated that the five factors explained 77.78 of the variation among the accessions. The results of path analysis showed that the leaf area, leaf length/width, number of flowers in inflorescence, phenolic content and shoot dry weight had effect in essential oil yield of accessions and phenolic content had the highest direct and positive effect (0.8). The results suggested that there was a considerable genetic variation among S. hortensis accessions.

One of approaches to reach sustainable agriculture is to exploit crop diversity, especially in legume species. Since Melilotus spp. (sweet clover) is a forage crop with a suitable yield especially in the marginal lands; therefore collection and characterization of this germplasm is the first effective step for its conservation and utilization in the country. Few accessions of Melilotus genetic resources had been collected in the National Plant Gene Bank of Iran, before this study.

Sweet clover genetic resources were collected all over the country using standard descriptors during two years. Twenty-six characteristics of collection sites were recorded and their descriptive statistics were estimated. The collected materials were planted in an experimental field to identify their life cycle. The seeds of collected germplasms were conserved in mid (2-4 °C)- and long (-20 °C)-terms conditions for further using.

A total of 258 accessions were collected. The geographical altitude of plant origin differed from -11 m in Babolsar to 3090 m in Noor Abad in Lorestan. The materials were mostly collected from non-saline habitats. However, eight accessions were collected from mid to high salinity locations. Taxonomically, M. albus, M. officinalis, and M. indicus were identified with a number of 21, 201 and 36 accessions, respectively. M. dentatus and M. sulcatus, which have been mentioned in the former researches in Iran, were not collected in the recent study.

The collected germplasms from marginal lands (saline, low drainage and low fertility lands) may be tolerant to such marginal lands, therefore they can be exploited for the future research. All M. indicus species were annual; whereas there were annual as well as facultative and obligate biennial accessions in the two other species. Lack of access to M. dentatus and M. sulcatus may be an alarm that they may be threatened species in the country. Collected materials in this study along with the former collection in the Iranian National Plant Gene Bank (80 accessions) have provided high potentials of Melilotus genetic resources for exploitation in the further. Highlights: 1- The three-fold increase in the Melilotus germplasms in the ex-situ conservation system. 2- Alarm for M. dentatus and M. sulcatus which may be threatened with extinction in the country.

To evaluate the effect of  deficit  irrigation stress at different growth stages of two Iranian melon accessions  on growth, yield and fruit quality, a split- split plot experiment was conducted based on randomized complete block design with three replications at University of Zanjan. Treatments were consisted of deficit irrigation in three levels (100, 80 and 60% ETc) as main plot, stage of water deficit application in two levels (flowering and 20 days after flowering (fruit development stage) as sub plot and melon accession in two levels (Khatooni and Ivanaki) as sub-sub plot. The results showed that deficit irrigation stress were conducted at two growth stages, reduced growths index and yield. The lowest leaf area, plant height, total plant yield (6.72 kg), marketable plant yield (5.47 kg), fruit flesh percentage (50.7%) and vitamin C (1.48 mg/100 ml were obtained under  60% ETc at flowering stage. The highest value of TSS was obtained in “Khatooni” (12.04%) and “Ivanaki” (11.42%)” by applying 80% ETc at flowering stage. The highest value of water use efficiency (WUE), was achieved in “Ivanaki” and “Khatooni under 80% ETc at flowering and” 20 days after flowering stage, respectively. The Ivanki accession showed higher tolerance to water deficit. According to the results, applying 80% ETc at the flowering stage improved the fruit TSS and resulted in 40% water usage, while reduced 6.61% of fruit yield.

To evaluate the percentage and degree of polymerization and yield of inulin, and also root fresh yield of 13 native accessions and two imported cultivars of chicory (Cichorium intybus L.), an experiment was conducted using randomized complete block design with three replications in Khoshkedaran Research Station of Mazandaran province, Iran, in three consecutive years (2016-2018). The roots were harvested at the end of the rosette stage in the second year of cultivation, then weighed and relevant calculations were performed. Samples were extracted by using aqueous extraction method, and their total sugar content and reducing sugar and the percentage and degree of polymerization of inulin were calculated. Means comparison showed that accessions "Rasht" and "Chamestan" and imported cultivar "Selenite" had the highest percentage of inulin (15.8, 13.9, and 14.3%, respectively) among the chicory genotypes. Findings showed that cultivar "Selenite" and accession "Tonekabon" were more superior to other genotypes in terms of fresh root yield and inulin and ranked first (35.458 t ha-1 fresh root and 2818.99 kg ha-1 inulin yield) and second (12.692 t ha-1 fresh root and 807.5 kg ha-1 inulin yield), respectively. In addition, "Selenite" and "Tonekabon" had good stability in terms of percentage and degree of inulin polymerization in two years of research and were found to be more suitable for the western region of Mazandaran province than other genotypes.

In this research a total of 49 accessions in oat collection of National Plant Gene Bank of Iran belonging to four species of Avena barbata, A. wiestii, A. fatua and A. sativa were studied. The experiment was performed in an observatory designin research field of Seed and Plant Improvement Institute located in Karaj, Iran. The agromorphological traits were measured according to IBPGR descriptor. Based on Shannon index, lemma color had the largest variety (1.42). In principal component analysis, the first seven components comprised 68.43% of total variation. Two accessions of 439 (A. barbata) and 449 (A. barbata) were the nearest and two accessions of 447 (A. wiestii) and 115059 (A. wiestii) and were the farthest based on genetic distance. The studied accessions were placed  in five groups by K means clustering method. Three discriminant functions were developed justifying total variance in data. The first and second discriminant functionsmaintained the most distinction between two species of A. barbata and A.sativa and between two species of A. fatua and A. wiestii, respectively. Total results indicated presence of suitable diversity in the studied population based on the measured traits which could be exploited in oat breeding in future. In addition, the discriminant functions developed in this research could be used in distinguishing the relating oat species.

One of the most important methods of conservation and survival of plants in nature is the cultivation and domestication of plant species to select the best population. According to the necessity of cultivating and domesticating medicinal plants, in this research, 22 accessions of Achillea wilhelmsii C. Koch were planted and evaluated in the Alborz Research Station, Research Institute of Forests and Rangelands. This research was performed in a randomized complete block design during 2013-2015. In order to study and compare the morphological characteristics of different accessions of this plant, the plant height, canopy cover, number of main stems, number of capitol per plant, number of florets in capitol, plant fresh and dry weight, and essential oil content were measured at 50% flowering. The extraction was carried out by water distillation method with Clevenger. Analysis of variance and mean comparison showed that the difference among the accessions was significant at 1% level. The results showed that Saqez 1 had the highest plant height, plant dry weight, number of capitol and florets and essential oil content. The correlation between the study characteristics was significant at 1% level; however, no significant correlation was found between essential oil content and other characteristics except for the number of capitol. Using the principal component analysis, the first five components explained 99% of the total variance of the variables. Canopy cover, plant height, number of stems, number of capitol, and plant fresh and dry weight, with a positive coefficient, had the most important role in explaining the first component and explained 75% of the variance of the variables. In the cluster analysis, the accessions were divided into three groups, and the Saqez1 accession was placed in a separate cluster as an indicator.

This experiment was conducted in order to evaluate resistance to drought stress of watermelon accessions, Isfahan, Sharif-Abad, Crimson sweat and Colocynth as index plant. Experiment performed in Randomized Completely Block Design as split plot with four irrigation regimes (100% as control, 75%, 50% and 25% of available water). Results showed that the longest shoot and high number of female flower was at 100% and 75% AW while the lowest level was observed at 25%AW.The highest water use efficiency obtained from Crimson sweat with 34/16 Kg/m3 at 75%AW. The maximum fruit yield (ton/hectare) was for Sharif-Abad in control treatment and minimum amount for crimson sweat at 25%AW without any fruit. Sharif-Abad and crimson sweat had highest contents of total phenolic compound with increasing stress level in comparison with other samples. As a whole, based on results, Sharif-Abad accession was more tolerant accession in stress conditions. In respect to Evaporation Transpiration and KC, crimson sweat allocated maximum and colocynth minimum amount. The use of local and tolerant watermelon in breeding program and irrigation management could help in overcoming water shortage.

To evaluate biomass and oil percentage at flowering stage in different accessions of medicinal plants Satureja spicigera (C. Koch) Boiss. (spic1, spic2, spic3)and S. sahendica Bornm. (sah1, sah2, sah3, sah4, sah5, sah6)under dry farming condition, an experiment was carried out based on three-replicated randomized complete block design in Damavand, Iran in 2014. Variance analysis showed significant differences (P

Colocynth is one ofdrought tolerant species, which is widely distributed in desert regions of Iran. The experiment was performed in research field of University College of Agriculture and Natural Resources, University of Tehran placed in Karaj, as a split plot based on randomized complete block design which irrigation levels were as main plot in two levels (100% and 60% field capacity) and accessions were as sub plot in seven levels (Kerman, Sistan and Baluchestan, Khuzestan, Yazd, Hormozgan, Bushehr and Isfahan).At the end of growth period, yield, yield components and indices of drought resistance were evaluated in two stress and non-stress conditions for screening of colocynth accesstions. The highest yield in stress and non-stress conditions belonged to Kerman (5.73 kg/plant) and Isfahan (2.54 kg/plant) accessions, respectively. Yield components of Isfahan accession showed the lowest variation percent in stress and non-stress drought conditions. Investigation of drought resistance indices and correlation between yield and these indices and principal components analysis showed that Isfahan accession was tolerant with sustainable yield, Yazd and Hormozgan accessions were semi tolerant with relative sustainable yield and Kerman accession had high yield in non- stress and stress drought conditions.Khuzestan and Bushehr accessions were low yield and high sensitivity to drought stress and Sistan and Baluchestan accessions were low yield and relative tolerant to drought stress. Generally Isfahan accession had high tolerant to drought stress and useful for commercial watermelon breeding programs.

Thymuskotschyanus Boiss. & Hohen. is a perennial medicinal shrub growing wild in some regions of Iran including Yazd province. This research was carried out in order to analyze oil quantity and quality of cultivated Thymuskotschyanus in the Medicinal Plants Farm, Yazd, Iran. The seeds of 19 accessions collected from natural habitats were sown in a greenhouse and the seedlings were planted in the farm. Shoots were harvested at 50% flowering stage in the second year and dried under shadow. Essential oil was extracted with water distillation method and oil components were identified after determining oil content. The highest amounts of oil content respectively were related to accessions TK7 (3.42%), TK12 (3.22%), TK17 (2.66%) and the lowest amount was observed in accession TK6 (0.79%). The highest amounts of oil production respectively were recorded in accessions TK5 (38.3kg/ha), TK7 (36.4kg/ha) and TK12
(36.1 kg/ha) and the lowest amount was related to TK1 (1.3 kg/ha). Cluster analysis based on eleven oil components classified the accessions into three groups. The first group, (TK2, TK6, TK13, TK18, TK16, TK19), was rich for thymol-p-cymene, the scond group (TK1, TK3, TK4, TK5, TK7, TK11, TK14, TK15, TK17) for carvacrol-thymol and the 3rd group (TK8, TK9, TK10, TK12) was rich for Geraniol-linalool. In general, accessions TK7, with 3.42% oil content, 36.4 kg/ha oil production and 63.8% carvacrol; TK14, with 2.2% oil content 35.5 kg/ha oil production and 47.2% carvacrol and thymol, TK5 with 2.4% oil content, 38.3 kg/ha oil production and 57% thymol and carvacrol are proposed as superior accessions.

Safflower is the most suitable crop plant for oil production in dry areas and regarding the fact of climate change, it has been come in consideration in recent years. A broad genetic base and rich germplasm is necessary for breeding of this crop. This research was performed in 2011 to investigate variability of safflower germplasm. A total of 345 accessions of safflower collection of National Plant Gene Bank of Iran were planted and evaluated in research field of Seed and Plant Improvement Institute in Karaj. Preliminary evaluation showed that many accessions consisted of several diverse morphotypes, hence, by isolating and morphotype determination, the number of accessions reached to 534, which were investigated in an observational design. The results indicated that corolla color and spine intensity of outer involucral bracts had considerable amount of Shannon index. The highest (85.62) and the lowest (7.24) coefficient of variation belonged to seed weight of single plant and days to flowering, respectively. The first three principal components justified 56.13% of variation, the first one emphasized on yield components and the second on vegetative traits. The accessions were located in five groups by K means clustering method. Distribution of country origin of the accessions was consistent with their geographical situation in some cases. Totally, results showed that the studied accessions have a considerable variation which could be exploited in breeding programs.

Landraces are a valuable source of genetic diversity for varietal improvement. Despite, Iran is the fifth squash and pumpkin producer, but no available information exists about the diversity of summer squash landraces. In order to evaluation of floral and fruit production characteristics among four Iranian summer squash and a check cultivar of F1 hybrid ‘Asma’, an experiment was conducted in a randomized complete block design (RCBD) with three replications. Each plot had four tagged sample plants of one accession. The results were demonstrated significantly substantial differences for number of node, node position to first female, number of female flower, female/male flower, number of harvested fruit from main stem, number of lateral branch/plant, number of harvested fruit from branches/plant and total harvested fruit/plant traits in studied accessions. Number of female flower ranged from a minimum of 8 to a maximum of 18. It was resulting to a broad variability in number of harvested fruit from main stem (5.2-12). There was a significant difference between Iranian landraces and check cultivar for floral and fruit production characteristics. Growth habit and number of female flower were two main factors that influenced fruit production/plant variability.

In order to investigate the quality and quantity of essential oil of Thymus species, an experiment was conducted under field condition at Research Institute of Forests and Rangelands. This project was related to national project, entitled extraction, qualitative and quantitative analyses of the essential oil of different Thymus species in some provinces of Iran. For This purpose, seeds of 75 accessions, collected from various provinces, were cultivated under greenhouse condition. Then, seedlings were transferred to the experimental field and cultivated under field condition. Flowering shoots were collected at 50% of flowering stage, dried in shadow and grinded. Essential oil extraction was carried out by hydro distillation method (Clevenger apparatus-Britain pharmacopeia) for three hours. Chemical compounds were identified with GC and GC-MS. According to the results, essential oil yield was between 0.04%-2%. The highest essential oil yield in relation to dry weight belongs to T. kotschyanus (2%), T. daenesis (1.92%) and T. vulgaris (1.69%) from west Azerbaijan province, Lorestan province and Markazi province, respectively. Linalool, geraniol, α-terpineol, Thymol, carvacrol, α-terpinyl acetate and geranyl acetate chemotypes were recognized among accessions. During two years, the highest Thymol (76.6%), carvacrol (82.9%) and geraniol (62.7%) were observed in T. daenesis from Markazi province, T. daenesis from Semnan province and T. lancifolius from Fars province.

Drought resistance of 24 accessions of Agropyron trichophorum was examined based on forage yield in a complete block design with three replications under normal and dry land farming system. Drought resistance indices of genotypes were measured for forage dry matter yield of two environment conditions including sensitivity to stress index (SSI), tolerance (TOL), mean productivity (MP), drought tolerant index (DTI), mean harmonic (MH) and geometrical mean of productivity (GMP). According to the results of variance analysis of drought resistance indices, significant variation was observed among accessions. Results of mean comparisons showed that genotypes 10 (Semirom), 23 (Mazandaran), 24 (Gorgan), 5 (Chaharmahal), 17 (Yasuj) and 9 (Eghlid) had higher values for forage dry matter yield in both environment conditions. With regard to the drought resistance indices, genotypes 10 (Semirom), 23 (Mazandaran) and 24 (Gorgan), showed the most resistance to drought stress. Obtained results were confirmed by results of cluster analysis and principle component analysis.