جستجوی مقالات مرتبط با کلیدواژه « Root length » در نشریات گروه « زراعت »

Chickpea is the third most important grain legume and its seeds contain protein that is an important energy source for human. Drought diminishes crop yields and carries the potential to result in total crop failure. However, chickpeas are renowned for their superior drought tolerance compared to many other cool-season legumes. Given that water availability is the primary constraint on growth in arid conditions, optimal yields and crop production occur when plants efficiently absorb the limited soil moisture available. This feature will only be achieved through the compatibility mechanisms associated with the root system. Chickpea have a direct and deep root system that helps the plant absorb moisture from the lower layers of the soil. Therefore it has led to the prosperity of its cultivation in rainfed areas. Water absorption by the plant depends on the size of the root, its activity and distribution in the soil. Therefore, it seems that the understanding of plant root traits is necessary to further understand the mechanisms of drought resistance. In general, few studies have been done on the diversity of legume roots. Therefore, this research was carried out with the aim of investigating the diversity of root morphological traits of chickpea lines in order to use these traits to select drought-tolerant chickpea lines.
 

The plant materials of this experiment included 39 chickpea lines of Icarda origin, which were taken from the Kurdistan Research Center. The experiment was conducted as a completely randomized design with four replications in the research greenhouse of Ilam University. Seeds were implanted in PVC tubes with a diameter of 10 cm and a length of 60 cm. A drip irrigation system was designed in such a way that an emitter was located inside each tube. With this method, the test tubes were in favorable conditions. In the greenhouse the temperature was under control and had a temperature of 25 degrees Celsius and an average humidity of 70% and the plants used natural light without any additional light. After 35 days of seed germination traits were measured. For this purpose, first the aerial parts of the plant were separated by scissors. After separating the roots from the PVC tubes, they were placed in ethanol with a concentration of 98% and after being transferred to the laboratory, they were stored in the refrigerator, then the traits were measured. Variance analysis of traits and average comparison of data was done with Duncans multi-range test using SAS software version 9.1.
 

All the measured traits had a good variation range among the studied chickpea lines that these results are consistent with previous studies. None of the lines showed superiority for all root traits. Line FLIP07-20C having the longest root length, can benefit from the water available in a larger volume of the soil profile. In the examination of rooting depth in grain legumes, such as chickpeas, it was observed that root length remains relatively stable across a broad spectrum of soil moisture levels. Root length is considered a crucial parameter in plant growth, as researchers posit that the length of roots per unit of soil volume is the most effective characteristic for assessing water and nutrient absorption by plants. In our current investigation, a significant disparity was noted between the highest and lowest root volumes. Root volume stands out as one of the plant's key attributes for absorbing water and nutrients. In this research, line FLIP 82-150C had the highest and line FLIP97-706C had the lowest specific root length. The specific root length is one of the important traits in showing the efficiency of the root in absorbing water and resistance to drought. When faced with drought stress, the plant assigns more dry matter to the root system in order to increase the absorption ability of the roots; as a result, there are changes in the morphological characteristics of the roots, such as an increase in the specific length of the root. The highest root density was observed in line FLIP09-149C. root density is a trait that is affected by root weight and volume. In the condition of drought stress, the decrease in root volume caused an increase in root density and at the end of the growth period, the decrease in root dry weight was more than the decrease in its volume, which ultimately led to a decrease in root density. Studies have indicated that as humidity decreases and soil depth increases, there is a notable decrease in root density. Overall, the findings from this research offer foundational insights for advancing efforts to enhance root characteristics, thereby mitigating drought and enhancing the resilience of chickpea varieties to drought stress.
 

The results showed that Line FLIP07-20C had the highest root length, root length density and root water content compared to other lines, but none of the lines were superior in terms of all root traits. The obtained information about the characteristics of the roots of the studied lines can be used to improve drought-resistant chickpea lines.

Heavy metals such as chromium are considered important pollutants for the environment and agricultural products. Many of these metals are toxic even in very low concentrations and may disrupt the growth process of crops. This study aims at comparing the response of different sesame cultivars to irrigation with different levels of chromium contaminated water. The experiment is carried out as factorial in a randomized complete block design with three replications in Mayamey, Semnan Province, Iran. Experimental factors include irrigation with different levels of chromium-contaminated water in 5 levels (20%, 40%, 60%, 80%, and 100%) and three sesame cultivars (Dashtestan, Oltan and local). The results indicate that irrigation with chromium-contaminated water significantly reduce the plant height and root length (p < 0.01), but have no significant effect on leaflet number and shoot fresh weight. The highest decrease in plant height and root length are observed under irrigation with 100% chromium-contaminated water. There has been a significant difference between sesame cultivars in relation to the growth characteristics. So, the Oltan cultivar has had the highest plant height, leaflet number, root length, and water productivity index compared to other cultivars. According to the results, high levels of chromium in irrigation water significantly reduce the growth of different cultivars.

The first factor limiting plant yield in many crop ecosystems is drought stress, and plant productivity under these conditions depends on the distribution of dry matter between plant organs and the spatial distribution of roots in the soil. Knowledge of root length conditions and its distribution in soil profile, which is an indicator of the ability of plants to absorb water from deeper layers and better root permeability in the soil, as well as understanding the shape of the root system, is important (Wasson et al., 2012). In general, the size, morphology, and architecture of the root system determine the plant's ability to absorb water and nutrients, as well as the relative size and growth rate of the shoot (Vamerali et al., 2003). Root growth is determined by the genetic characteristics of the plant as well as the physical and chemical characteristics of the soil. Even in wet areas in response to drought stress, root growth is limited to the topsoil, and when the soil dries, its infiltration resistance increases rapidly, resulting in a combination of drought stresses. Soil and its infiltration resistance (He et al., 2017). Reduction of root dry weight in rice (Nasiri et al., 2015), fresh weight of root in rapeseed (Razaviezadeh and Amoubeigi, 2013) indicate the negative effect of drought stress on root characteristics in Different plants. Tillage is the only crop method by which humans can directly affect soil properties. Moisture storage and aeration to the roots, depending on the desired or unfavorable application of tillage, affects the growth and development of plant roots and ultimately its yield (Bronick and Lal, 2005).

This experiment was conducted in split -split plots based on randomized complete block design with three replications. Tillage systems as the main -plot in two factors was including no tillage and conventional tillage, Water stress as the subplot in three levels by 30, 60 and 90 Percent of moisture requirement and nitrogen urea as the sub-sub plot at three levels by 0, 50 and 100 percent of the recommended rate.

The combined variance analyses indicated that the maximum root length (4147 cm per plant), root volume (158.13 cm3 per plant), root area (3055.7 cm2 per plant), root length density (0.44 cm2. cm-3), root dry weight (24.32 gr pl-1) and plant fresh weight (6732.6 gr. m-2) was obtained from the interaction of conventional tillage in mild drought stress (90% of the plant's water requirement) in 100% of the plant's nitrogen fertilizer requirement. Also, the interaction effect of severe drought stress (30% of plant water requirement) in 100% of plant nitrogen fertilizer requirement led to a sharp decrease in studied traits in both studied tillage systems. Although the conventional tillage system in this study ultimately increased the root growth characteristics and fresh weight of the forage maize plant, but because no significant difference in wet forage yield was observed in both studied tillage systems, the system no tillage is recommended because it can improve the physical and chemical properties of the soil in the long turn.

In order to investigate the effect of salinity on some root characteristics and ion distribution, a research was carried out in a split factorial on three replications with two salinity levels (2 dS.m-1) and 16 dS.m1 (salinity) on six wheat cultivars (Atrak, Pishtaz, Chamran, Roshan, Qods, and Shiraz) and in two levels of harvest (two weeks and three weeks after planting) in greenhouse. The traits of root dry weight, shoot dry weight, shoot dry weight/root dry weight ratio, root length, total volume, sodium ion concentration, potassium ion concentration, potassium/sodium ratio in root and shoot, number of axial root, number of first and second- order lateral roots were measured. The results showed that salinity in the second and third week reduced the dry weight of root, shoot, length, root volume, axial, and first-order lateral root number in all cultivars. In the control treatment Chamran and Roshan had the highest ability to produce root and shoot dry weight respectively. Under salinity the highest root dry weight (14 and 18 mg/plant) and total root volume (78 and 93 mm3 /plant) were related to Roshan in both weeks. Qods had the lowest root dry weight with the highest drop (54% and 50%, respectively) in second and third week. The lowest total root volume in salinity of second and third week respectively was related to Qods and Shiraz (40 and 59 mm3 /plant).Qods with high root producing potential in control showed a significant decrease in the production of lateral roots and total root length in salinity. Also, Roshan cultivar, despite having the highest sodium concentration of shoots in salinity treatment, it was able to produce the highest amount of shoots due to maintaining potassium ions in roots and shoots. Based on the traits evaluated and the response of the studied cultivars to salinity, tolerance of the Roshan cultivar and susceptibility of Qods cultivar to salinity arecompatible with previous study at this stage of growth.

To evaluate the soil residue of imazthapyr effects on cotton and maize, an experiment was carried out based on completely randomized design at greenhouse of Agricultural Faculty of University of Gonbad Kavous. Different doses of imazthapyr (0, 4.5, 23, 45, 68, 91, 140, 180, 230, 340 and 450 μg.kg-1 soil) were applied on maize and cotton and finally the dry weight of root and shoot, shoot height, root length and leaf area of crops were measured. Three and four Log- logistic curves were fitted to the data. Results indicated that almost all data fitted better to the three parameter log- logistic curve. Results of separate fitting of the data showed that the residue of imazthapyr always reduced dry weight of crops. For 50 percent reduction of shoot dry weight of cotton and maize, 13.26 and 21.91 g.a.i.ha-1of imazthapyr were needed respectively. To reduce 50 percent of root dry weight of cotton and maize, 72.75 and 25.19 g.a.i. ha-1of imazyhapyr were needed. Generally, the results of data simultaneously fitting showed that maize root and shoot sensitivity to imazthapyr were always more than cotton. Shoot height, root length and leaf area were decreased as imazthapyr residue was increased.

Fitness costs of herbicide resistance may be more evident and increase under stress environmental conditions. To test this hypothesis, a herbicide-resistant (R) and a herbicide-susceptible (S) phenotype with controlled and homogenized genetic background were isolated within a non–target-site resistant (NTSR) black-grass population. Accumulated maximum germination (Gmax) and time to reach the Gmax (G50) of biotypes were examined under non- and abiotic-stress conditions (salinity at 16 dSm-1, drought at -0.8 Mpa). In addition, seedling pre-emergence growth of the biotypes were evaluated at non-stress condition. There was no difference in Gmax between the R and S biotypes, whereas the Gmax of R phenotype was 28% and 49% lower than that of the S phenotype under salinity- and drought-stress conditions, respectively. The R phenotype germinated around seven to 16 hours later than the S phenotype under all non- and abiotic-stress conditions, i.e. the R phenotype had higher G50 than the other phenotype. The experiments of seedling pre-emergence growth showed that the R and S biotypes had similar root and shoot length under non-stress condition. The results clearly showed that the germinability fitness costs of NTSR black-grass increase when the plants are grown under salinity- and drought- stress conditions.

temperature and light in a completely randomized design with 8 surface temperature (5,10,15,20,25,30,35,40 Degrees centigrade) in terms of continuous light and continuous darkness with 4 replicators at the research laboratory of Ramin Ahwaz Agricultural and Natural Resources University in 2017. The results showed that temperature and light treatments had significant effect on germination percentage, seedling vigor, root length and shoot length. Temperature of 35 ° C and constant light conditions showed the highest germination percentage. Cardinal temperatures for germination of base temperature, the optimum temperature and maximum temperature, respectively, 7/6, 34/6 and 40 ° C respectively. The highest seed vigor index was observed at 35 ° C and continuous light conditions.

Black cumin (Bunium persicum Bioss) is a small and perennial herbaceous plant. During the first year of the growth, this plant produces only cotyledon leaves and small root that becomes to underground tuber after growth. Lack of sufficient rainfall with irregular patterns over black cumin growing areas cause drought stress during different growth periods of plant, especially during the first and the second years of plant growth when tubers do not well formed. Therefore, this study was planned to evaluate moisture stress impacts on the growth of black cumin during the first year of its growth.

In order to investigate the effect of moisture stress on black cumin, an experiment was carried out in a factorial experiment based on completely randomized design with three replications at College of Agriculture, Ferdowsi University of Mashhad during 2014. The factors were included plant population in three levels (Kuhbanan, Sirjan and Kalat) and three levels of moisture stress [100, 75 and 50% of Field Capacity (FC)].
During mid-April, seed dormancy was broken by the GA and chilling. Germinated seed were planted in pots (diameter 10 cm, height 15 cm) at a depth of 1-2 cm. Pots was irrigated at FC level for up to two weeks after seedling establishment . After that pots weighted, and if the weight decreased from FC, added water to reach the desired pot weight. At the end of the growing period (seven weeks after drought stress in mid-June) all plants in each pot were harvested. Plant height, root length, shoot and root dry weight, tuber diameter and tubbering percentage were measured. Samples of shoot and root were placed in oven at 75°c for 24 hours and then their dry weight were measured by a digital scale with accuracy of 0.001 g.
Statistical analysis was performed by using the software MSTATC and the means were compared by using the LSD test.

The results showed that the differences between populations for all traits were significant, except for root length and shoot/root dry weight ratio,. The effects of moisture stress and population and their interactions were significant for all traits. Plants in all populations, at 50% FC were killed due to drought stress. Kalat population at 75% FC had the maximum length of roots and shoots. Also, at 75% FC Sirjan population had the most reduction in shoot dry weight. At 75% FC Kuhbanan and Sirjan populations had 15% reduction in height while this reduction in Kalat population was 24%. Root dry weight at 75% FC in all populations was less than 100% of FC. In all population the tuber was formed only at 100% FC and plants grown at 75% FC did not produce tubers.

Results demonstrated that reducing the soil moisture from 100% FC had negative impacts on the growth traits of black cumin. Since the black cumin is a perennial plant, it would be useful to study the effects of moisture stress during different years

Salinity is an environmental factor that affects all stages of plant development from germination to fruit and grain production more or less. Germination is one of the most critical stages in plant growth under salt stress conditions. In order to investigate the effect of salicylic acid on germination and growth characteristics of Fenugreek seedlings seedlings under salinity stress, an experiment was carried out in a factorial experiment in a completely randomized design with three replications in 2017 in Agriculture and Technology Laboratory, University of Mohaghegh Ardebili. Experimental factors included concentrations (0, 0.5 and 1 mM) of salicylic acid and salinity levels including zero (control), 50, 100 and 200 mM sodium chloride. The results showed that with increasing salinity percent and germination rate, seedling length, seedling dry weight and Fenugreek weight decreased. Germination percentage (50%), germination speed (35%), seedling length (40%) and seedling dry weight (45%) were obtained at 200 μm salinity (without salinity). Application of 1 mM salicylic acid could significantly improve the traits compared to the control. The results of this study showed that the use of salicylic acid could greatly endure fungal strain under stress conditions.

Extended abstract Quinoa, with the scientific name (Chenopodium quinoa Willd), belongs to the Spencer family. Seeds vigor can be improved with a variety of seed priming methods. In this method, the seeds are soaked in water or various osmotic solutions and then dried to the original moisture. After priming treatment, seeds are stored and cultivated as untreated seeds. Potassium nitrate is the most frequently used chemical for the purpose of increasing seed germination and is recommended by the Society of Official Seed Specialists and the International Association of Seed Testing for germination experiments of many species. In recent years, the use of nanoscale materials has been of great interest to researchers. Chitin, one of the most abundant polysaccharides in nature, is a polymer chain of N-acetyl glucosamine and is associated with other proteins and other organic compounds, and numerous industrial, pharmaceutical and agricultural applications have been reported for it. The present study was carried out to investigate the effects of chitosan nanoparticles and potassium nitrate on some morphological characteristics, germination characteristics, chlorophyll content and relative humidity of quinoa plant. In order to investigate the effect of pretreatment of quinoa seeds with chitosan nanoparticles and potassium nitrate solution on the early stages of germination, a factorial experiment was conducted in a completely randomized design with four replications in Seed Processing Laboratory, Faculty of Agricultural Sciences and Natural Resources, Shahed University, Tehran, Iran. Experimental treatments consisted of priming with chitosan nanoparticles in 4 levels (no primers, 0.01, 0.20 and 0.04% w / v) and potassium nitrate in 3 levels (no primers, 0.2 and 0.5% Weight percent) and hydroperime for 2 hours at 25° C. For each replicate of every treatment 100 seeds, using standard priming methods, were treated with the materials mentioned above and were dried in a petri dish on Watman paper No. 1 at 20 ± 1 ° C and relative humidity of 70% and 16 hours of daylight and 8 hours of darkness to make germination work. After that, germination percentage, root length, shoot length, germination coefficient, Allometric coefficient, relative water content, chlorophyll content a and b were measured, using standard methods. Seed treatment with 0.2% potassium nitrate solution increased germination by 9% and treatment with chitosan 0.01% increased germination by 14%, compared with the non-primer treatment. The priming treatment with a 0.5% solution of potassium nitrate and 0.01% chitosan increased germination by 36%, compared to the non-primer treatment. Potassium nitrate increased root length by 25% and shoot length by 10%. In addition, chitosan 0.01% increased the root length by 6%, and seeds with chitosan 0.02% and potassium nitrate 0.2% increased the root length by 32%. The effects of potassium nitrate, chitosan and their interaction on chlorophyll a and b were significant at 1% probability level. The highest levels of chlorophyll a were obtained in 0.02% chitosan and 0.2% potassium nitrate. This formulation increased the chlorophyll a content by 33%. The highest amount of chlorophyll b was obtained by applying 0.01% chitosan and 0.5% potassium nitrate. The results of this study showed that treatment with 0.01% w/v chitosan and 0.5% w/v potassium nitrate resulted in the highest germination percentage, chlorophyll content a and b, relative water content, and stem length. Treatment with 0.02% chitosan and 0.2% potassium nitrate resulted in the highest allometric coefficient and root length.


Highlights: Chitosan nano particle and potassium nitrate increase quinoa germination.
Chitosan nano particle and potassium nitrate increase the content of chlorophyll a and b

Water scarcity causes rice yield loss more than 30% under drought stress at field conditions. Hence, employing drought tolerant cultivars in this condition is an effective way to overcome such a challenge. Therefore, in current research, we have used three Iranian rice cultivars named Amol3, Sang-tarom and Neda, which is originated from a cross between Amol3 and Sang-tarom, in order to investigate responses of the selected rice cultivars to drought stress. In this study, several important physiological characteristics were evaluated under drought stress during a growth period. Therefore, present study was aimed to achieve some information about mechanisms and responses to drought stress and to use them in identifying tolerant cultivars in drought stress situation as well as employ them in rice breeding program.
The rice seedlings of three genotypes were tested at greenhouse under three levels of water treatments as: control (FTSW=1.0, Fraction of Transpirable Soil Water), mild drought stress (FTSW=0.5) and severe drought stress (FTSW=0.2) in four replications in 28±2ºC in day and 25± 2º in night and in 14 L/10 D light period in a factorial arrangement of treatments in randomized complete block design in PVC pipes with 1-meter-long and 10 cm in diameter. The root length, stomatal aperture size, ABA content in leaves and wet and dry weights of panicles were measured as essential features in these cultivars in both drought stress levels and in control treatment. For data analysis SPSS and SAS software was applied.
In this study, we found that in rice cultivar Neda, showed a significant reduction (P In Neda, no significant reduction was observed in stomatal aperture size while the maximum dry and fresh weights of panicles was found in Neda under mild drought stress condition, which could be a remarkable sign among the cultivars in long-term drought stress. A total of 30% reduction was observed for grain yield of Neda while the yield loss for Amol3 and san-tarom were 58% and 50%, respectively. Reduction in ABA level in leaf, root length stimulation and stomatal aperture size regulation could be assigned to the behaviors in highly tolerant cultivars under drought stress condition. Neda showed more similar responses to Amol3, one of its parent, than to Sang-tarom regarding increasing in root length and reduction in ABA level in leaf in response to drought stress. A good correlation between root length and reduction in ABA level or redistribution of ABA in root for better hydraulic conductivity and also preventing ethylene action in drought stress that needs to be more studied.

Salinity is one of the most important environmental stresses that affect the growth and yield of plants. To study the effect of salinity and salicylic acid on germination of cucumber (Cucumis sativus cv. Super Dominus) and watermelon (Citrullus lanatus cv. Crimson Sweet) seeds, two factorial experiments were conducted in a completely randomized design with three replications. Treatments consisted of four levels of salinity (0, 2, 4, 6 ds/m sodium chloride) and three levels of salicylic acid (0, 0.5, 1 mM). The results showed that salinity significantly reduced seed germination and seedling growth. The lowest values of germination rate in cucumber (18.79) and watermelon (10.33), germination percentage in cucumber (86.65 percent) and watermelon (69.63) and seed vigor index in cucumber (17.93) and watermelon (9.59) was observed in 6 ds/m level of salinity. Salicylic acid improved germination parameters in both plant. The highest seed germination (97.98 percent) was obtained in the 1 mM level of SA under control condition. According to the results, pretreatment of cucumber and watermelon seeds by 1 mM SA can be proposed to improve seed germination and growth rate of seedling under salinity.

To study the root structure and its morphological characteristics of winter and durum wheat cultivars, an experiment was carried out based on randomized completely design with four replications at faculty of Agriculture, Ilam University during 2013-2014. Experimental treatments consisted of six bread wheat cultivars (Sardari, Keras Sabalan, Nestor, Pistaz, Bahar and S83-3), four durum wheat cultivars (Karkheh, Dena, Sora and Saji). Traits under study were seminal roots, nodal roots, sub-nodal roots, number of total roots, seminal roots length, nodal and sub-nodal roots, total root lengths, root dry weight, root volume and root to shoot ratio. The results showed significant differences for root structure of bread wheat cultivars (Sardari, Keras Sabalan and Nestor). They had stronger root system than the other bread wheat cultivars.It was also found that Saji from durum and Sabalan cross from bread wheat cultivars had the highest number of total roots (seminal, nodal and sub-nodal roots), root length total (seminal, nodal and sub-nodal roots), root volume and root/shoot ratio as compared with the other cultivars under study. Orthogonal contrast for three groups of genotypes indicated that in terms of number and length of nodal roots, bread wheat cultivars showed higher values as compared to durum wheat cultivars.

In order to evaluate the effect of salt stress on seed germination, early growth and antioxidant enzymes activity of Chicory ecotypes (Cichorium intybus) a factorial experiment was conducted based on completely randomized design with four replications at College of Agriculture, Shiraz University in 2013. The treatments were included five salinity levels [tap water (0.62), 3, 6, 9, 12 dS m-1] of sodium chloride and chicory ecotypes (Black and White). The results showed that germination rate and germination percentage were decreased in both ecotypes with increment of salinity severity. In both ecotypes, the highest germination (100%) was observed in tap water and 3 dS m-1 and the lowest germination (37%) was obtained at 12 dS m-1. The lowest root (14.2 mm) and shoot length (12.45mm) was obtained at 12 dS m-1 respectively. The effect of salt stress on antioxidant enzyme activity was significant, so that those were enhanced with increment of salt stress; however, increasing in salinity level from 9 to 12 dS m-1 was associated with reduction in peroxidase activity in Black ecotype. The results of this study revealed that the White species was more affected by increasing in salt concentration, so it had more sensitivity salt stress. The salt tolerance also had a positive relationship with the antioxidant enzymes activities in Black ecotype, especially for catalase.

In order to evaluate the effects of wastewater irrigation on sugar content and morphological traits of sugar beet (Beta vulgaris L.), an experiment was conducted in split plot design based on randomized complete block design with three replications at Research Station in Shahrekord University in 2013. The treatments consisted of irrigation with urban wastewater at 2-4 and 8-12 leaf stages, and irrigation with normal water (control) in main plots, and four types of fertilizer including sheep manure, mushroom compost, chemical fertilizer, and no fertilizer (control) in sub-plot. Results showed that irrigation at 8-12 leaf stage significantly increased single root weight, shoot fresh weight, root length and diameter in comparison with control. However, copper and manganese concentration in shoot, sugar content, and white sugar content were not influenced significantly. Fertilizer treatments had significant influence on the aforesaid traits. The maximum single root weight, shoot fresh weight, and root length and diameter were observed in sheep manure treatment and irrigation at 8-12 leaf stage.

This research was conducted to evaluate the effect of mild and intense drought stresses on root traits and some anti-oxidative enzymes and to identify drought tolerant genotypes in tall fescue. Twenty-four genotypes were assessed under three levels of moisture regime (control, mild and intense drought stresses) according to a factorial experiment based on a completely randomized design with three replications. The genotypes were clonally propagated and planted in PVC tubes (60×16 cm). Results indicated that the effect of moisture regime, genotype and their interaction were significant for all of the measured traits. Under mild and intense drought stress, the root length, root dry weight and dry forage yield decreased compared with control. Intense drought stress increased the root/shoot ratio about 25 percent. The activities of catalase and ascorbate peroxidase decreased under intense drought stress compared with control and mild drought stress, while the activity of peroxidase increased in this level of stress. Results showed that some tall fescue genotypes under drought stress had high yield productivity, desirable root and anti-oxidative systems indicating that these genotypes had drought avoidance and drought tolerance mechanisms which can be used for future breeding programs.

Root depth and distribution have an important role in drought resistance and optimization of moisture content of soil. This research was carried out in order to consider of root response of triticale genotypes to water stress and recognition of root trait that can effective in resistance of water stress. This experiment was in a factorial experiment based on completely random design on the year 2009. The genotypes of triticale was included (i) ET-82-15 (ii) ET-82-8 (iii) ET-82-17 and commercial triticale genotype Juanillo-92. Two irrigation regimes included 100 and 50 % of field capacity، respectively. The result showed that water stress result in increased 9% of root depth in each plant. Differences between minimum root depth was observed in ET-82-15 rather than maximum root depth in Juanillo-92 was approximately 8. 2 centimeters. Late irrigation caused to diminish 25% of root length. Differences between maximum root length in ET-82-15 and minimum root length in ET-82-17 was not significant (p)