جستجوی مقالات مرتبط با کلیدواژه « Morphological » در نشریات گروه « زراعت »

Fusarium rot disease is one of the most important fungal diseases of saffron corms worldwide, which can lead to a decrease in product yield and the quality of daughter corms produced. The objective of this study was to isolate and identify agents responsible for Fusarium corm rot in saffron, as well as to assess their pathogenicity. In order to determine the Fusarium species from saffron corms with rotting symptoms were sampled from the different fields in provinces of Hamadan, Golestan, Kerman, Kurdistan, Semnan, Kermanshah, Ardabil, East Azerbaijan, North Khorasan, Razavi Khorasan, Isfahan, and South Khorasan. After isolation and purification, fungal isolates were identified and confirmed based on morphological characteristics and species-specific primers. Also, the pathogenicity of the isolates was artificially tested in the greenhouse on saffron corms according to Koch’s principles. The results indicated that approximately 38.6% of the saffron corms were infected with fusarium rot disease in the 1 to 5% range. 33 isolates were identified based on morphological and molecular characteristics belonging to F. oxysporum (26 isolates, 78.8%) and F. solani sensu lato (7 isolates, 21.2%). The pathogenicity tests revealed that all Fusarium isolates were pathogenic, displaying varying levels of disease index.The result of the host range test of F. oxysporum on different plants revealed that all isolates caused wilting and yellowing of aerial organs, necrosis and rotting of underground organs on Gladiolus (Gladiolus communis L.), Irises (Iris germanica L.) and Crocus (Crocus vernus L.) and was called as F. oxysporum f. sp. gladioli. This is the first report on identification of F. oxysporum f. sp. gladioli from saffron fields in Malayer, Bijar, Kangavar, Parsabad, Marand, Natanz, Najafabad and f F. solani sensu lato from saffron fields in Azadshahr, Shirvan, Esfarayen, Kashmar, Najafabad, Boshruyeh on saffron corms. The findings of this research provide new insights into the health status of saffron corm against fusarium rot disease, which can be used for the revision of the national standard for saffron corms and determining suitable areas for certified corm production of saffron.

In order to investigate the effect of planting date on agronomic and physiolocal characteristics of maize hybrids in different groups in Jiroft region of Kerman province, an experiment as a split plot in the randomized complete block design with three replications in the city of Jiroft in the crop year 2017-2018 was conducted. Experimental factors were included planting date as the main factor at three levels of July 27, August 3 and August 10 and different hybrids as a secondary factor at 10 levels of early, late and medium maturing hybrids (701, 703, 705, 706, 707, 201, 260, 400, 370 and 704 as controls). There was a significant difference between the studied hybrids in terms of agronomic and physiological characteristics. The highest number of rows per ear was obtained in hybrid 706 and the highest number of seeds per row was obtained in hybrid 707. Delaying in planting was associated by of increasing stem diameter and biological yield and decreasing of plant height, ear length, number of rows per ear, seed yield, harvest index, GDD to physiological maturity and spad. By Delaing in planting, seed protein percent and proline accumulation increased. The most seed yield was obtained on July 17 in hybrid 260 (18.24 t.ha-1), August 3 in hybrid 210 (17.46 t.ha-1) and August 10 in hybrids 370 and 201 (17.4 and 17.28 t.ha-1). It seems that the delayed planting date due to exposure to unfavorable temperatures during tillering, pollination and granulation, as well as the reduction of the growing period was decreased yield and yield components.

Rapeseed is one of the most important oilseeds in the world. Rapeseed with the scientific name of Brassica napus L. is ranked third in the world in terms of grain production after soybean and in terms of oil production after soybean and oil palm. Plants are always exposed to a wide range of environmental stresses, both biological and non-biological, that strongly affect their growth and production. Cold stress and frost are one of the environmental factors that affect crop production and other important agronomic traits in many plant species. Frost in the early stages of germination causes the destruction of the whole plant. The amount of frost damage depends on many important factors such as the duration and severity of frost stress, different stages of plant growth period and the amount of air humidity. Rapeseed is sensitive to frost stress and shows a yield reduction of up to 70%.Identifying cultivars that tolerate low temperatures can help researchers improve new cultivars and increase the flexibility of choosing the right planting date for farmers. Various studies have been performed to evaluate canola genotypes against cold stress in terms of morphological or physiological traits, but few studies have been conducted to study the combined traits. This study was designed to identify frost stress resistant genotypes, evaluate the effects of frost stress on yield and yield components as well as physiological traits to identify and modify the traits affected by the stress.

In this experiment, 24 autumn Rapeseed genotypes were obtained from the oilseeds section of Karaj Seed and Plant Breeding Research Institute. Selected genotypes included a number of promising lines and free pollen and rapeseed hybrid cultivars, including: SLM046, Opera, L963, Okapi, L62, Nima, KH4, Talayeh, L957, Ahmadi, KR18, L1009, Zarfam, Nafis, HW101, Licord, KS7, L14, SW101, L1008, L83, L120, Natali and Hydromel. Experiment with two different planting dates as normal sowing on 10/6/1397 and delayed sowing on 6/25/1397 in the form of split plot design based on randomized complete blocks with three replications in 1397-98 crop year It was implemented in the agricultural lands of Tikmeh Dash city of East Azerbaijan province. Morphological traits including number of pods per plant, number of seeds per pod, 1000-seed weight, yield per hectare and physiological traits including leaf chlorophill, proline, malondialdehyde, soluble sugars, electrolyte leakage percentage and superoxide dismutase were measured.

The effects of frost stress were significant for three traits: number of pods per plant, 1000-seed weight and yield at 1% probability level, and this indicates that delay in planting all cultivars tested caused a decrease in yield and its components. The mean squares of genotypes were significant for two traits: number of seeds per pod and yield at 1% probability level. Mean stress squares were significant in terms of chlorophill b, proline, soluble sugars, electrolyte leakage, malondialdehyde and superoxide dismutase at the level of 1% probability. There was also a significant difference between the genotypes in terms of the above traits as well as chlorophill a and total chlorophill at the level of one percent probability. The results of comparing the mean of genotypes together for stress-free and frost stress conditions showed that KS7 line with 1699.9 kg ha-1 had the highest average yield and the lowest was related to L62 line with 107 kg ha-1. According to this study, the decrease in yield is due to the decrease in the number of pods per plant as components of grain yield. Both under stress and non-stress conditions, the total yield showed a positive and significant correlation with the number of pods per plant and the number of seeds per pod. In non-stress conditions, no correlation was observed between yield and physiological traits, while in frost stress conditions, there was a positive and significant correlation between yield with proline, soluble sugars, malondialdehyde and superoxide dismutase, so this can be Introduced traits as positive traits for selecting frost-resistant cultivars. Based on the results of factor analysis, 4 factors were identified for each of the conditions without stress and frost stress, which in the non-stress state was 77.52% of the total variance and in the frost stress state was 81.06% of the total variance.

According to the results of the correlation between the studied traits, it was found that in non-stress conditions, the number of pods per plant and the number of seeds per pod can be used to improve grain yield. In terms of frost stress, in addition to the number of pods per plant and the number of seeds per pod, the amount of proline, soluble sugars, malondialdehyde and superoxide dismutase had the greatest contribution in justifying the diversity of studied genotypes. Due to the low heritability of the yield, it is usually difficult to improve. As a result, other aspects of frost stress resistance, such as physiological parameters, should be considered. In general, physiological traits provide more complete information and are a good alternative to functional traits.

In order to investigate the effect of salicylic acid and jasmonic acid foliar application onsome morphological traits of artichoke (Cynara scolymus L.) under salt stress conditions,an experiment was conducted in 2014 at Islamic Azad University, Yadgar-e-ImamKhomeini (RA) Shahre Rey Branch. The experiment was done as factorial based oncompletely randomized design with four repetitions, the experimental factors include:salinity stress in four levels: 0, 25, 60 and 95 mM, salicylic acid foliar spraying in twolevels non-use (control) and 0.7 mM consumption and spraying of jasmonic acid wasconsidered in two levels: no consumption (control) and 100 µM. The results of varianceanalysis showed that the simple effects of salinity stress, application of salicylic acid andjasmonic acid were significant on all investigated traits, and among these traits, rootlength, number of leaves and root dry weight were influenced by the triple interactioneffects of experimental factor. The simple mean comparison results indicated that undersalt stress conditions with 95 mM sodium chloride, the lowest plant height (41.93 cm),root length (9.79 cm), number of leaves (4.62) , the leaf area of a single plant (140.73),the fresh weight of aerial parts (12.93 grams), the dry weight of aerial parts (2.46 g) androot dry weight (1.42 g) were obtained. The highest amount of shoot dry weight )7.42 g(observed in non salinity stress and spraying with 100 µM jasmonic acid and themaximum amount of root dry weight )3.03 g( were gained in non salinity stress, using 0.7mM of salicylic acid and 100 μM of jasmonic acid conditions. Therefore, it can be statedthat the use of salicylic acid and jasmonic acid as anti-stress agents improved all themorphological characteristics of the artichoke medicinal plant.

This study was conducted to evaluate the effect of sulfur on morphological traits of promising L17 line of canola at Mazandaran Agricultural and Natural Resources Research and Education Center-Baye Kola Research Station based on randomized complete block design with three replications in 1397-1398. In this research, the different traits such as plant height, number of pods in main shoot, total number of pods, number of seed in pod, combinatory height, pod height, oil content, protein content, oil yield and protein yield were measured. The obtained results from analysis of variance showed that the effect of all sulfur treatments on the traits studied were significant at level of 1%. The resultant outcomes of mean comparison exhibited that the sulfur treatments of 200 and 300 kg/ha had the highest effect on the above mentioned traits. In addition, the correlation results indicated that seed yield had the most and positive correlation with 1000 weight seed (0.831), total pod (0.672) and number of pod in main shoot (0.649), respectively. Thus, it is possible to use these traits as selection criteria for further crops improvement of promising L17 line of canola.

Background and Objectives:

 Iran owns a good resources of apple genotypes which are mostly located in north of Iran beside Caspian sea. These genotypes have different phenotype. As initial step some of these samples were collected and different traits were measured and ranked. To look at rate of anthocyanin and Phytochemical and physical and chemical traits this experiment was designed and performed. Variation in size and skin and pulp color and phytochemical traits this experiment was designed. Differences in different characters can lead breeders for using the genotype within a breeding program. The presence of genetic diversity leads to more adaptation of Plants to different environments and selects superior genotypes. Since diversity in neoplasm is important in breeding programs. This study was conducted to evaluate different apple varieties using morphological and phytochemical characteristics using multivariate statistical methods. For this purpose, a study was conducted in 2016 in a completely randomized design with 12 varieties of native and imported apple in three replications.

Materials and Methods :

The fruits were collected from Kamal Shahr Horticulture station of Karaj, affiliated to the Seed and Plant Improvement Institute. A total of 11 traits including weight, volume, density, firmness, acidity, total soluble solids and other characteristics were evaluated. The obtained data were subjected to analysis of variance using SAS (9.1) software and Duncan's test were calculated for the mean comparisons.

Results :

Analysis of variance showed that there is a meaningful difference between genotypes for all studied traits. According to the results, fruit weight varied from 161.9 grams in Fuji cultivar to 4.25 gr for Gol-ghermez cultivar. Acidity varied from 0.88% for Gol-sefid to 0.16% for Shahrood 10 genotype. The percentage of TSS varied from 19.5% for Red delicious cultivar to 11.5% for GH2 genotype and Golab-Kohanz cultivars. The highest positive correlation (0.95) was observed between fruit weight and Fruit volume. Based on the results of PCA, the cultivars were divided into three distinct groups, which were similar to cluster analysis results.

Discussions :

The results revealed native Iranian apple varieties and genotypes are rich in genetic diversity and can play an important role in future apple breeding programs. The results revealed native Iranian apple varieties and genotypes are rich in genetic diversity and can play an important role in future apple breeding programs.The results revealed native Iranian apple varieties and genotypes are rich in genetic diversity and can play an important role in future apple breeding programs.

The aim of this study is to identify  Fusarium species associated with root and corm of saffron and evaluate extracellular enzyme activity secreted by them. In order to study the species of Fusarium, a total of 53 root and corm samples were randomly collected from saffron fields of the South Khorasan province during 2017 growing season. After washing the samples with sterile water and disinfected the surface with 1% sodium hypochlorite, small pieces of root and corm were cultured on general and specific culture media. Purification of fungal colonies was performed using single spore and hyphal tip methods on 2% water agar medium. Identification of fungi based on the microscopic and morphological characteristics was performed with valid identification keys. The F. oxysporum, F. graminearum, F. culmorum and F. proliferatum species were identified based on morphological characters. The results obtained from molecular analysis using species-specific primers confirm morphological identification. The results reveal that 22.6% of saffron samples are contaminated by Fusarium species. F. oxysporum is the predominant species with the highest isolation frequency in samples of 9.4% followed by F. culmorum (5.7%), F. proliferatum (3.8%) and F. graminearum (3.8%) based on morphological and molecular observations,

Determining the relationship between morphological, physiological and biochemical (qualitative) characteristics is necessary to increase the production and quality of horticultural products, such as strawberries. Over time, a variety of statistical approaches have been emerged in order to evaluate the relationships of variables, and old-fashioned statistical solutions have gradually replaced with new ones with more scientific and reliable results. Meanwhile, the new PLS-PM approach, due to its new methodology and more reliable and attractive results, has more applications than classical sttatistical methods.

Some morphological traits, flower, fruit, qualitative (biochemical) and yield in eight genotypes of strawberry were studied in a randomized complete block design with three replications for four years. Different statistical methodologies were utilized i.e. estimating correlation coefficients, stepwise regression, simple path analysis, and to gain a more accurate relationships, data analysis algorithm performed with advanced PLS-PM approach (including Cronbach's alpha, factor load coefficients, path coefficients and coefficient of determination, the goodness of fit and cross-loadings).

The results showed that despite genetic variation among cultivars, there was a significant correlation between fruit yield with fruit traits, number of leaves, flourescence characteristics and number of crowns per plant, and fruit size and anthocyanin level. The number of flourescence, size, volume and number of fruits, date of formation of runners and flowering period accounted for 88.3% of the variation of yield and its most important components. Number and size of fruit had the most direct effect on the increase of fruit yield. Flowering had the most effect on fruit yield and then morphological traits had the most effect on biochemical and inflorescence traits. The size and volume of fruit was affected by morphological traits more than others.

In this study, various statistical approaaches have been used for understanding the relationship between evaluated traitsin of strawberries, where none of them was as suitable as the recent but unfamiliar PLS-PM approach, indicating the important effect of flowering characteristics on increasing the fruit yield of strawbwrry. Applying the new PLS-PM method in comparison with the old statistical methods, and by categorizing the traits, it was concluded that due to their different nature, in relation to the increase in the yield of fruit yield, flowering traits were more effective compared to the other traits, and the morphological traits including: height of inflorescence, number of leaves, ear length, crown length, start date, number of runners and leaf area are also influential traits that can be used to manage strawberry breeding programs and economic production.

Nigella sativa is an herbaceous and annual plant in the family of Ranunculaceae, which cultivated in different parts of Europe and Asia, including in Iran (various regions, especially Arak and Isfahan). The plant has small leaves and white flowers with blue margin. Salinity stress is one of the major environmental stresses due to low osmotic potential of soil solution (osmotic stress), ionic toxicity (ionic stress) and nutritional disorder, or a combination of these factors in the plant as one of the most important factors limiting growth and development of plants. In order to study the morpho-physiological and biochemical responses of Nigella sativa plant to salicylic acid under salinity stress conditions a split plot experiment with two factors carried out based on completey randomized design with 3 replicates in the greenhouse of the Medicinal plants research center of Shahed University in 1396. The salinity factor with 4 levels (0, 3, 6, 9 dS/m) in main plots and salicylic acid levels in 4 levels (0, 25, 5 0 and 0.75 mM) were investigated in sub plots. Salicylic acid levels were sprayed on plants one week before applying salinity stress (about 4 to 6 leaves) and three weeks after salinity stress conditions. After 21 days of treatment, the effect of salinity stress on growth traits (shoot length, number of branches, number of leaves, root length, fresh and dry weight of shoot, fresh and dry weight of root), physiological traits (chlorophyll a, chlorophyll b and carotenoid, proline, malondialdehyde and catalase and superoxide dismutase were investigated. The results showed that different salinity concentrations had significant effects on morphological and physiological traits. By increasing salinity levels, the growth indices such as number of branches, number of leaves and chlorophyll b and the amount of superoxide dismutase and malondialdehyde decreased, while by increasing the salinity levels the content of proline and catalase in leaf increased. The results showed that applying salicylic acid under salinity stress reduced the growth indices and photosynthetic pigments. The highest number of branches, number of leaves and chlorophyll b was obtained at 3 dS/m salinity and 0.5 mM salicylic acid. Also, by increasing salicylic acid level, the activity of the proline content and leaf cattalase increased, but with increasing the salicylic acid levels, the amount of malondialdehyde and superoxide dismutase enzymes decreased. Based on the results, it can be concluded that the Nigella sativa is a semi-sensitive saline plant. The overall results showed that salicylic acid increased the plant tolerance to salinity stress. However, for a better conclusion on the effect of salicylic acid, the use of this compound is needed in a wider range. For example, in most of the studied physiological and biochemical traits, no significant difference was found between the effects of various salicylic acid concentrations. While positive effect of salicylic acid cannot be ignored in improving the damage caused by stress. In general, the use of salicylic acid resulted improving in biochemical parameters and increased plant tolerance to salinity stress. Therefore, it can be concluded that applying the salicylic acid can be a suitable procedure to reduce the harmful effects of salt stress in Nigella sativa.

Almond has a high sensitivity to salt stress. Selection of a tolerant rootstock/scion is one of the ways to reduce the negative effects of salinity stress. In this experiment, the effects of salinity stress on some morphological, physiological and nutritional traits of some almond rootstocks was investigated in a factorial experiment based on completely randomized design with two factors (8 levels of rootstock/scion compositions and five levels of salinity) in three replications at Horticultural Research Institute in 2017. The results showed that by increasing salinity from zero to 8 ds/m, the highest and lowest amount of reduction in root dry weight was observed in ‘Shahrood 12’/Tetra (37.8%) and GN15 (14.5%), respectively. The lowest and highest dry weight loss in the main branch was observed in the bitter almond seedling (38.2%) and ‘Shahrood 12’/ GN15 (47.9%), respectively. The highest amount of necrosis was observed in bitter almond seedling (28.98%) and the lowest value was in ‘Shahrood 12’/GF677 (9.9%). The lowest and highest changes in electrolyte leakage occurred at the rootstock of GF677 (30.74%) and GN15 (42.93%). The lowest and the highest changes in sodium were observed in the ‘Shahrood 12’/GF677 (51.2%) and in the bitter almond seedling (82%), respectively. The results also showed that by increasing salinity stress, the amount of root and leaf nutrient elements increased initially and then decreased with increasing salinity levels. Based on the results, ‘Shahrood 12’/GF677 is the most tolerable combination and the ‘Shahrood12’ grafted on bitter almond seedling is the most sensitive to salt stress.

In order to investigate the contamination of cotton seeds with Fusarium fungi, samples of different classes of 10 cotton cultivars were obtained from Southern Khorasan, Razavi, Golestan and Fars provinces. Various sections of a seed such as full seed, coat, kernel (endosperm and embryo), endosperm and embryo were cultured on the nutrient medium of potato dextrose agar and water agar. Of the 23 cotton seed samples, 76 isolates of Fusarium was obtained. The contamination in fuzzy and delinted seeds were 98.7 and 1.3 percent respectively. The hightest percentage of purified Fusarium was from kernel. Identification based on morphological traits showed that the isolates with the frequency of 39, 23, 10, 2, 1 and 1 isolates belonging to the species Fusarium equiseti, F. proliferatum, F. semitectum, F. compactum, F. nygamai and F. solani. Species of F. compactum and F. nygamai are reported for the first time from Iran. The application of Polymerase chain reaction and the use of specific primers of F. equiseti and F. proliferatum dominant species have led to the production of proprietary DNA bands using the DNA of the relevant fungal species, as well as the seed DNA that naturally contaminated these species. In this way, the results of identification of these two species based on morphological traits were confirmed by the molecular method. This study revealed that Fusarium traces are detected in infected seeds using the PCR reaction.

Exact classification of parental lines between hetrotic groups is necessary for improvement of hybrid rice breeding programs because it can help breeders in parental selection and prediction of F1 hybrids yield. In this research, genetic distance of 18 parental and 40 male sterile lines were evaluated based on morphological, floral and palynological traits. Cluster analysis indicated that Neda male sterile lines were placed in first sub-group and also Nemat male sterile lines were in second sub-group of the first group. Dasht A (Dasht × IR68899A), Khazar A, Hasani A, Gerde A, Sang Tarom A, Shastak Mohammadi A and their maintainer lines were in one separate group. Therefore, these lines had high purity after seventh backcross. The results of this research can be used for selection of suitable CMS lines used in breeding projects of hybrid rice to find high performance progenies.

Water shortage in root environment is the main factor limiting crop growth and productivity in dry regions. There are many reports on the role of methanol spraying for increasing drought tolerance in C3 plants. For this reason, a factorial experiment was conducted using completely randomized block design with 3 replications at Khatam Alanbia University of Behbahan. Methanol applied with five levels; (control, 5, 15, 25 and 35% v/v) and water deficit stress with three levels: irrigation at 100% of field capacity, moderate water stress, irrigation at 75% of field capacity and severe water stress, irrigation at 25% of field capacity. Foliar application of methanol was applied 3 times during the growing season (at seedling, flowering and podding stages) with 10-days intervals. Results showed that the interactions of methanol × drought on the root dry weight, root diameter, root length (p<0.05) and root area (p<0.01) were significant. In normal irrigation conditions, methanol spraying 5, 15 and 25% increased significantly root dry weight as compared to control. Also, the interactions of methanol ×drought on protein and proline were significant (p<0.01). Methanol spraying incresed significantly root proline and protein contents. Interactions of methanol and drought on sodium and potasium consentration, (p<0.05) and calcium (p<0.01) was significant. Interactions of methanol ×drought on root activities of superoxide dismutase and peroxidase were significant (p<0.05). Also, the effect of drought stress on catalase enzyme activity was significant (p<0.01). Methanol spraying decreased root activities of superoxide dismutase and peroxidase, significantly.

IntroductionLow temperature stress is one of the important abiotic limiting factors for plants growth, production and distribution. Low temperature also reducing plants biological activity and their economical yield. In spite farmers are regulated planting data of sugar beet to reduce plants damage from cold and frozen stresses in moderate and cold regions but, there are several reports which show root and sugar yield reducing due to cold stress especially at the early growth stages. This study aimed to investigate the effect of low temperatures on the morpo-physiological traits of sugar beet varieties at seedling stage, and to introduce cold tolerant genotypes and effective cold tolerance related characters of sugar beet plants.
Material and methodIn order to study of cold tolerance of number of sugar beet cultivars, an experiment was conducted at Agriculture Faculty of University Yasouj in 2013-2014. Seedling of ten sugar beet cultivars {(Karaji, SBSI- 005, Shirin, Rastad, Zarghan, Persia (Iranian cultivars) and Anaconda, Dorothy, Merak, Antic (exotic cultivars)} at stage of 2 to 3 leaves (25 days after planting) exposed to four levels of temperature including: 0, 5, 10 and 25º C (as a control). The experiment for each temperature level was completely randomized design with three replications. In order to application of cold stress the pots were placed in a growth chamber at the above mentioned temperatures. Physiological and morphological traits of seedling plants including: shoot height, shoot and root dry weight, electrolyte leakage, proline content, SPAD number, total soluble sugars content and chlorophyll fluorescence were measured. Stress tolerance index (STI) calculated based on shoot and root dry matter. Combined analysis of variance was done and means of main (temperature and cultivar) and interaction effects were compared using LSD and LSmeans methods, respectively. Descriptive statistics, genetic and phenotypic coefficients of variation and broad sense heritability were calculated. Stress intensity for all the above mentioned traits was calculated and the most affected traits by cold stress determined based on its value. Data were subjected to factor analysis using principal component method and the most important factors were interpreted. Four factor scores were calculated and cultivar classification was done using three-dimensional scatter plot based on scores of the first three factors.
Results and discussionResults of combined analysis showed that the effects of temperature, cultivar and their interaction were significant for the all measured traits. There was high diversity among the studied sugar beet cultivars for cold stress tolerance. Based on the results, cultivars showed different responses to temperature levels. The means of shoot (68%) and root (77%) dry matter reduced in stress condition (0˚C) than control condition (25˚C) but, the means of electrolyte leakage, proline content, total soluble sugars content increased 25, 90.5 and 71% respectively, in cold stress condition (0˚C) than control condition (25˚C). The highest genotypic correlation was observed between shoot height and total soluble sugars (-0.67) in non-stress (25˚C) and between root fresh weight and shoot dry weight (-0.43) in cold stress (0˚C) conditions. Leaf proline content had the highest (0.9) stress intensity indicating that it was most affected by cold stress. Shoot height had the highest (75.09%) broad sense heritability so; this trait can be transmitted to next generation. Factor analysis identified 4 factors in the cold stress (0˚C) condition that justified 71.7 percent of total variation. The first three factors were related to cold stress tolerance. Genotypes grouping using three-dimensional plot based on the first three factor scores, introduced Merak and Antic cultivars as cold tolerant, Drothy and Anaconda cultivars as semi-cold tolerant and other cultivars as cold sensitive.
ConclusionIn general, results of this investigation showed that there is enough genetic diversity of cold tolerance in sugar beet cultivars at seedling growing stage. In this study proline content, Fv/Fm ratio and root dry matter played key role in genotypes grouping based on their response to cold stress. The tolerant cultivars had high amounts of these traits than other cultivars. The results of this investigation can be used in sugar beet breeding programs to improve cold tolerance at seedling growth stage.

This experiment was conducted to determine morphological and physiological responses of perennial ryegrass (Lolium perenne L.) at the germination and early seedling growth stage to drought stress and sodium nitroprusside (nitric oxide donor) application in horticultural science department at the University of Zanjan in 2015. Turfgrass seeds were soaked for six hours in 0 (distilled water), 200, 400 and 600 micromolar of sodium nitroprusside solutions, and for drought stress treatments, germination and early seedling growth was done over the water potential range of 0 (distilled water), -1, -4 and -8 bar by polyethylene glycol. Generally, decline in water potential reduced seed germination percentage, root and shoot length, leaves chlorophyll and carotenoids content, whereas electrolyte leakage and proline content increased with decreasing of water potential. Sodium nitroprusside application at 400 and 600 µM ameliorate adverse effects of drought stress in all factors. However, in all water potentials, 600 µM treatment had no significant difference with control plants in electrolyte leakage, whereas 400 µM treatment reduced electrolyte leakage. Leaves proline content increased with decreasing water potential. Besides, treated plants with sodium nitroproside had more proline than untreated plants.
In conclusion, among different investigated sodium nitroprpside concentrations, treated plants with 400 µM sodium nitroproside showed the best results.

Mechanical stresses such as wind stress can have an important role in adaptation and ecophysiology of plants. Generally, reducing plant height, leaf area reduction, increased stem diameter; fresh and dry weight loss is the most common reactions of plants against mechanical stresses of wind. Wind blowing could increase respiration, transpiration and reduce the water content, so changes the chemical composition of the cell wall and changes in hormone production of plants. Moreover, by increasing the intensity of the wind stress may be plants face faced with lodging. Lodging impede the flow of water and nutrients needed by plants and prevents the flow of assimilated substrate in photosynthesis to the developing roots or seeds, as a result, kernel filling is impaired. As well as, lodging increases relative humidity in a plant community that lead to mold growth and spread of disease. Many areas of Iran facing with intense winds at the wheat reproduction stage, and due to the erectness of its culm, lodging could be happened. There is enough variation in tolerance of wheat cultivars against wind, therefore the effects of mechanical stress caused by the wind blowing in two wheat cultivars; Rowshan (tall and old) and Sirvan (new and semi-dwarf) were evaluated.
According to the above cases In order to evaluate the effects of mechanical stress caused by the wind blowing in the wheat, a three-factor factorial experiment in a completely randomized design with three replications was conducted in the experimental greenhouse of Ferdowsi University of Mashhad in 2014. The factors included the wind speed (5,10 and15meters per second) indifferent wind blowing duration (15, 30and45minutes) and two varieties of wheat; Roshan (tall and old) and Sirvan (new and semi-dwarf). For applying the treatments, pots were placed in a special chamber for mechanical wind stress in the same greenhouse.
Results showed that the amount of plant height, plant leaf number, height of first node after treatment applying, plant dry weight, were decreased with the increase of wind speed and wind duration in both the Sirvan and Roshan cultivars, the decrease was less in the Sirvan compared to the Roshan. In both cultivars the greatest amount of above mentioned traits were observed in control treatment without wind. According to the experimental observations, it can be argued that the lodging caused by the wind leads to damage in the plant. It seems that regarding more resistance of the Sirvan against lodging, the cultivar was less affected by damage caused by the wind.
In general, Sirvan compared with Roshan, was less affected by wind stress and decreasing trend of the studied traits on Sirvan was less severe. Sirvan is a semi-dwarf cultivar that is resistant to lodging, that's why it seems that the cultivar was less impressed by increasing the speed and duration of the wind blowing.

The present study was carried out in order to examine the effects of different cultivation dates on the properties of panicle and the yield of rice cultivars using a split plot design in the form of a randomized complete block basis with three replications in the crop year of 2010-11. The main factor was cultivation date at three stages (26 May, 10 and 26 July) and the sub-factors were Red Anbouri (long and short) and Champa. The results of the variance analysis indicated that the effect of cultivation date and the cultivar on the yield of the rough rice was significant at a level of 1%. First cultivation date resulted in maximum total dry material with an average of 13810 Kg.ha-1, maximum flag leaf width with an average of 1.14 cm, height with an average of 120.89 cm, and number of plants with an average of 504 plants per square meter. The second cultivation date caused the maximum flag leaf length with an average of 33 cm, day up to 50% of flowering with an average of 108 days. The third cultivation date led to the maximum yield of rough rice with an average of 4269.33 Kg.ha-1, harvest index with an average of 40.01%, the number of florets and seeds with averages of respectively 187.67 and 161.44 per cluster, the dry weight of flag leaf with an average of 0.14 gr and day until full maturity with an average of 144 days. As a result, the third cultivation date due to avoid susceptible panicle emergence to heat stress, is the best time of rice cultivation to achieve the highest agrain yield in Kuhzestan.

Study and evaluation of genetic diversity in European pear (Pyrus communis L.) is an important task in the pear breeding programs. This research was carried out in order to evaluate morphological, physiological and pomological variations within the some of the pre-selected European pear seedling genotypes in comparison with `Shahmiveh’ as a reference cultivar. The obtained results showed significant differences within the studied pear seedling genotypes in terms of the mentioned traits. Principal coordinate analysis (PCA) indicated that the studied characters could be placed in four components, explained about 94.02% of the total variability. According to the cluster analysis, the studied genotypes were divided into three groups. A95 was found to be in the same grouping with ‘Shahmiveh’ as one of the important commercial European pear cultivars in Iran. The same grouping of A95 with `Shahmiveh’ suggests that this genotype (A95) is superior in terms of suitable vegetative growth and higher fruit quality, among the studied genotypes and in comparison to the reference cultivar. Genotype A95 indicated a better ranking, than `Shahmiveh’ as a reference cultivar, in terms of fruit taste, attractive fruit with red halo color on the skin and suitable vigor with higher productivity, leading to the conclusion that it is as a promising European pear genotype. Further research will continue in the framework of new cultivar release within the pear breeding program at TMU, Iran.