جستجوی مقالات مرتبط با کلیدواژه "stress tolerance index" در نشریات گروه "زراعت"

IntroductionWater deficit compared to other abiotic stresses is the most important factor limiting the growth and production in all crops, especially wheat. Investigating the response of crop plants under stress conditions is the best way to produce drought-tolerant cultivars and improve yield under stress conditions. The challenge of breeding for drought stress tolerance in all crop plants, is to achieve a rapid screening method of genotypes and genetic improvement of yield under these difficult environmental conditions. The objective of this experiment was to identify high-yielding and water deficit tolerant genotypes in an F4 generation population of bread wheat.Materials and methodsThe plant materials of this experiment were 90 genotypes of the F4 generation resulting from a cross between two bread wheat cultivars (Arta, a spring cultivar sensitive to salinity and drought stresses, and Arg, a tolerant cultivar to salinity and drought stresses). These genotypes along with the parents, were evaluated in split plots based on randomized complete block design with three replications under two conditions (normal irrigation and non-irrigation from the pollination stage) in the research farm of Faculty of Agriculture, Tabriz University, Tabriz, Iran, in 2014. Evaluating the genotypes were done by simultaneous application of stress tolerance index (STI) based on yield-related traits including grain yield (STI-Y), spike weight (STI-S), 1000-grain weight (STI-1000) and harvest index (STI-HI) and identifying the relationship between these indices using genotype × trait biplot analysis. The studied genotypes were ranked based on the relationships in the biplot, and the high yield and water deficit tolerant genotypes were identified.Research findingsThe results of biplot showed that the first two principal components explained 72% (46% and 26%, respectively) of total variance in the studied population. Acute and closed angle between the STI-Y, STI-S and STI-HI vectors indicated a positive correlation between these traits, while the open and obtuse angle between the STI-Y and STI-HI traits with STI-1000 showed a negative correlation between them. In contrast, an quadrant angle was observed between STI-S and STI-1000 vectors, indicating that these two traits were independent and uncorrelated. In total, according to the relationships in the biplot and based on the combination of STI-Y and STI-1000 vectors, genotypes No. 84, 45, 89 and 15 were identified and introduced as the highest grain yield and most water deficit tolerant genotypes.ConclusionThe results of this experiment led to identification of superior and promising genotypes with higher yield potential and more tolerance to water deficit stress. Genotypes No. 84, 45, 89 and 15, which were superior to the stress-tolerant parent, after the purification steps, can be introduced as suitable genotypes for cultivation under water stress conditions as well as in normal environments. These genotypes can be used as drought tolerant parental lines in future breeding programs.

Crop yield products reduction due to abiotic stress is estimated at 51 to 82%. Most plants are exposed to environmental stresses, and water deficit is one of the most important non-abiotic stresses in limiting and producing crops around the world, especially in arid and semi-arid regions. Plants have developed various strategies to cope with water deficit stress, including morpho-physiological and biochemical.Wheat is one of the most important crops in the world, which in 2020 had the highest area under cultivation at the rate of 221.33 million hectares (with a total production of 766.03 million tons) worldwide. In the same year in Iran, the area under wheat cultivation was 6.70 million hectares and its production was 16.75 million tons.

The research was performed in research farm of Rainfed Agricultural Research Station Gachsaran, Iran, over 2020-2021 cropping years. In this study, 100 lines obtained from the landrace bread wheat of different origins from several continents and several countries were studied. The experiment was performed in a simple lattice design 10×10 with two replications and separately in two environmental conditions of stress and non-stress. The operation planting is done in January after conventional tillage implementation of the area by hand. The source of moisture supply for both rain fed (water deficit stress) and irrigation (no stress) test conditions was rainfall and sprinkler irrigation before the phonological stage of flowering (pollination (Zadocs scale 61)). Irrigation interruption was applied at the beginning of flowering in a stress environment (water deficit stress conditions) which continued until harvest, but the environment without stress in two times when wheat plants to early reproductive stage, flowering stages, and the beginning of grain filling (Grain paste stage (Zadocs scale 61-83)) Irrigation was performed. In this study, 16 morphological traits and grain yield were measured under both stress and non-stress conditions, including flag leaf length and width (cm), flag leaf pod length (cm), and flag leaf area (cm2), number of nodes and leaves per stem, internodes number, peduncle length (cm), plant height (cm), tiller number, fertile and infertile tillers of number, length of awn (cm), spike length (cm) and spike yield (g).

The results of the analysis of variance showed high and significant variability in both non-stress and deficit water stress. TRI 3492 was the most tolerant of geographical origin in Nepal and TRI 4549 had the lowest STI relative to deficit water stress of geographical origin in China. The highest and lowest heritability in stress conditions were related to plant height (98.02%) and the number of intermediate nodes (25.00%), respectively. The greatest decrease in heritability (66%) due to stress conditions was the leaf sheath length of the flag leaf. Among the traits studied in this study, flag leaf area with 31.41%, flag leaf length with 25.25% and grain yield with 23.53% had the highest percentage of stress reduction. The results of cluster analysis of the studied genotypes in both environmental conditions are in six separate and different groups so that the greatest difference in genetic distance and grain yield in both environmental conditions was observed between the first and sixth clusters.

Using the genotypes of first cluster (TRI 403, TRI 4013, TRI 3981, TRI 10340, TRI 5262, TRI 4549, TRI 2513, TRI 2656, TRI 3477, TRI 3242, TRI 3526, TRI 3513, TRI 4116 and TRI 4113) with 6TH cluster (TRI 10296, TRI657, TRI755, TRI752, TRI757, TRI 11020, TRI691, TRI 6129 and TRI754) Can be used in crossbreeding programs as well as genetic studies (such as recombinant populations and association mapping) and to increase the rate of heterosis used in water-deficit stress conditions.

Salt stress affects 20% of global cultivable land and is increasing continuously owing to the change in climate and anthropogenic activities. Globally, wheat is cultivated on non-saline and saline soils, covering an area of approximately 214.79 million hectares (Becker-Reshef et al., 2020). Salinity stress negatively affects the growth and development of wheat leading to diminished grain yield and quality. For this reason, it is important to develop effective strategies to improve yield through salt tolerance. The breeding of salinity-tolerant cultivars through selection and breeding techniques is one of the effective methods in the production and exploitation of saline soil and water.

In order to study the effects of salinity stress on grain yield, phenological and morphological traits and salinity tolerance indices among bread wheat elite lines, two separate experiments in a randomized complete block design with three replications were conducted in two saline and normal environments during two cropping years of 2019-2021. 20 wheat cultivars and elite lines cultivated at the South Khorasan Agricultural and Natural Resources Research and Education Centre. After determining the grain yield in both conditions, MP, GMP, TOL, HARM, STI and SSI indices were calculated and using SAS software, their correlation with grain yield was investigated and using STATISTICA software, the three-dimensional distribution of each cultivar and line was plotted. Combined analysis of variance was performed to determine the main and interaction effects in the two years of the experiment and the means were compared by Duncan's multiple range test at the level of 5% probability. Bartlett's uniformity test was performed before the combined analysis of variance. Analysis of variance and mean comparison was performed using SAS-9.0 software and cluster analysis was performed by Ward method through StatGraphics program.

The reaction of wheat lines were different in two environments and salinity stress reduced grain yield. The experimental results showed that different wheat lines react differently to salinity stress. Salinity stress decreased grain yield and morphological traits in all lines compared to normal conditions. Salinity stress shortens intermediates and reduces plant height and consequently leaf and shoot dry weight by reducing cell proliferation and reducing dry matter accumulation (Dura et al., 2011).The difference between cultivars and lines in terms of all phenological, morphological and grain yield in two years of the experiment was significant, which indicates the existence of appropriate diversity in the wheat elite lines. The existence of this genetic diversity can be very useful for selecting high-yielding wheat cultivars in salinity conditions. In the first year of implementation, Narin, line No. 3 and Barzegar with an average of 6494, 6227 and 6072 kg/ha, respectively, in normal conditions and Barzegar, line No. 18 and Narin with an average of 6361, 6166 and 5805 kg/ha respectively, had the highest grain yield under salinity stress. In the second year of the experiment, line number 16, 10 and 4 with an average of 5388, 5305 and 5155 kg/ha in normal condition and Narin, Barzegar and line No. 3 with an average of 4930, 4611 and 4180 kg/ha respectively, had the highest grain yield under salinity stress. Naturally, wheat lines grain yield under salinity stress was lower than their yield under normal conditions. Under these conditions, the plant leaf area of is greatly reduced, which reduces the photosynthetic capacity of the plant, and as a result, the amount of dry matter produced and ultimately the grain yield of the plant is reduced (Munns et al., 2002).

For selecting wheat cultivars and lines in the areas that are most exposed to salinity stress, YI, HM, GMP, STI, MP, RSI and YSI indices and in areas not exposed to salinity stress, MP and STI indices are suggested. Barzegar and Narin check cultivars and line number 10 were determined as the most tolerant and lines No. 14, 13 and 20 as the most sensitive lines to salinity stress by different indices. Cluster analysis of lines based on STI index led to the placement of Barzegar and Narin cultivars and lines No. 3, 4 and 18 in the first cluster in which the mentioned lines have fewer days to heading and in contrast more days to maturity, grain filling period, thousand-grain weights and higher grain yield.

Durum wheat is considered as the 10th most important crop in the world. Drought stress is among the principal constraints to global wheat production. Improvement of new varieties having good adaptation to stressful conditions is an important goal of wheat breeding programs. In this regard, the exploitation of genetic diversity retained in landraces and wild relativesis is very important. The aim of this research was to evaluate durum wheat landraces collected from different contries for drought tolerance.

In this study 196 durum wheat landraces belong to 18 countries were evaluated for drought tolerance using several yield-based drought indices. The trials were conducted in the experimental field of dryland agricultural research institute (Sararood branch) based on alpha lattice design with two replications under rainfed and supplemental irrigation conditions during 2020-2021 cropping season.

Analysis of variance revealed significant environment, genotype, and genotype × environment interaction effects for grain yield. Based on genotype-by-index (GI) biplot analysis the drought selection indices were classified into four groups. The first group included drought response index (DRI), yield stability index (YSI), yield index (YI) and yield under rainfed condition. The second group composed of stress tolerance index (STI) and geometric mean productivity (GMP) which were able to select genotypes producing higher yield in both conditions. The third group included mean productivity (MP) and yield under irrigated condition. Fourth group composed of stress susceptible index (SSI), tolerance index (TOL), Schneider’s Stress Severity Index (SSSI) and yield reduction percentage (RI) which were able to separate genotypes having higher yield in non-stress and low yield in stress condition. Cluster analysis identified three distinct groups having different yield performance and drought tolerance.

Generally, based on the results of this research, selection for higher values of DRI, STI and GMP and lower values of SSI, TOL and RI at the same time can be considered as a appropriate strategy for identification of drought tolerant landraces. The members of first group which mostly composed from landraces belong to Iran, Japan, Turkey and Afghanistan could be considered as high-yielding drought tolerant.

To evaluate safflower genotypes under saline conditions and select tolerant genotype(s), 18 safflower genotypes obtained from Dryland Agricultural Research Institute, Iran, were planted at three salinity levels (2, 6, and 12 dS m-1) as main plot and genotypes randomized in subplots using split plots arrangements in randomized complete block design with three replications in Sadough salinity research station, Yazd, Iran, in 2016-17 and 2017-18 growing seasons. Gentypes were selected based on their performance at different salinity levels as well as using stress tolerance indices. The mean reduction in seed yield in the first and second growing season at 12 dS m-1 salinity level relative to control was 36% and 51%, respectively. The STI, MP, GMP, HM, Yis, Yip and MSTI1 indices were highly correlated with seed yield in three environments. Using principal component analysis the first component designated stress tolerance and the second component was salinity stress susceptibility. The results of cluster analysis using stress tolerance indices that had high correlations with seed yield showed that genotypes 4, 26, 34 and 35 were superior to control (cv. Faraman) and grouped in one group, however, genotype 6 performed the same as control. Selected genotypes had higher seed yield in three salinity conditions. In conclusion, LRV-57-57, 26-S6-58-11, Local Kurdistan, Isfahan 4 and PI-537682 with average seed yield of 172, 120, 152, 155 and 141 g m-2, at 12 dS m-1 salinity level, respectively, were selected as salinity tolerant genotypes.

Drought stress has reduced the yield and cultivated area of faba bean in many regions of Iran. So,in order to identify the best drought stress tolerance indices and select drought tolerant genotypes,24 genotypes of faba bean from ICARDA (International Center for Agricultural Research in DryAreas) drought resistance nursery and control cultivar (Barekat) were planted in two separateexperiments at Gorgan and Gonbad agricultural and natural resources research stations (GolestanAgricultural and Natural Resources Research and Education Center). Faba bean genotypes wereevaluated in a simple lattice design with two replications in 2015-2016. To determine droughttolerant genotypes, it is necessary to grow them under both stress and non-stress condition. To thisend, various stress tolerance indices such as tolerance (TOL), Stress Sensitivity Index (SSI), MeanProductivity (MP), Stress Tolerance Idex (STI), Geometric Man Poductivity (GMP), Yield Index(YI), Modified Stress Tolerance Index (K1STI) were calculated based on the genotypes in stressedyield in stress and non-stressed conditions. Multiple variance analysis of data showed that therewas a significant difference between the genotypes. In medium stress conditions (SI = 0.46), therewas a correlation between bean pod yield in stress and non-stress conditions, which indicates theability to generalize the yield results in non-stress to moderate drought stress conditions. MP,GMP, STI, HM, YI and K1STI indices can be used to identify tolerant genotypes due to theirpositive and significant correlation with yield in both stress and non-stress conditions. Therefore,1, 3, 12, 19, 20, 21, 22, 23 and 24 genotypes were selected for further investigations in thecrossbreeding program of drought resistance.

The phenomenon of reduced potato yield have increased in recent years under adverse conditions, such as water stress. The effects of water stress on yield and yield component of three potato cultivars have been evaluated in this study during 2019 growing season. This investigation has been arranged as split-plot experiment, based on a randomized complete block design with three replications at Rozveh Agricultural Research Station (Chadegan, Isfahan, Iran). The main-plots are assigned to irrigation levels (75% and 100% field capacity) and sub-plots to potato cultivars (Marfona, Agria, and Atousa). To ensure the initial establishment of the plant and prevent severe crop failure, one additional irrigation has been performed at the establishment stage, with two supplementary irrigations performed at the tuber initiation stage for all plots. There has been a significant interaction between irrigation level and cultivars for tuber yields (α<%1) as well as other traits (α<%5). In water stress conditions, yield and water use efficiency of Atousa, new cultivar, are more than the other cultivars. Marketable yield of Atousa cultivar is about 40% higher than Marfona and Agria cultivars. The new cultivar produces 6.53 kg of tubers per cubic meter of water, while water use efficiency for Marfona and Agria is only 4.82 and 5.02 kg m-3, respectively. In conclusion, it is suggested that Atusa cultivar in both water stress and in normal conditions is more suitable for cultivation in the study area than in Marfona and Agria cultivars.

Potato (Solanum tuberosum L.) as a drought sensitive crop is one of the main sources of human nutrition in different countries and it is cultivated almost all over the world. It is predicted that among the 25 studied countries, the decline in potato yield in Iran between 2040 and 2069 will be 13.3% for drought-adapted cultivars and 48.3% for non-drought-adapted cultivars. Annually 164.4 thousand hectares of agricultural lands in Iran are allocated to potato cultivation with a yield of 32.4 t ha-1. Nowadays, plant biology is experiencing great advances in studies related to the complex behavior of higher plants, and stress memory is one of these progresses. Stress memory involves the accumulation of signaling proteins or transcription factors and epigenetic mechanisms in plants that leads to an improvement in the stress response when plants are exposed to a subsequent stress event. “Stress memory” in plants is also an essential feature of “intelligent” behavior and can be investigated at different levels.

In order to investigate the effect of drought stress on yield and yield components of four potato cultivars, a study was conducted in 2020 in Rozveh Agricultural Research Station, Chadegan city. Half of the required seed tubers were obtained from the previous year's experiment. The treatments were laid out in a split plot arrangement in a randomized complete block design with three replications. Main plots included two irrigation treatments (100% and 75% of the field capacity) and sub-plots included four potato cultivars (Agria, Marfona, Atousa, and Anousha). Each plot consisted of four rows with four m length and 75 cm × 25 cm of plant density. At harvest time, two meters of the middle rows of each plot were used to estimate yield and yield components. Stress tolerance index and water use efficiency were investigated in this study. SAS software (version 9.1) was used to analyze the data and Duncan's multi-domain comparison method (5%) was used to compare the means.

The effect of irrigation treatment on total yield, marketable and non-marketable yield, and on water use efficiency was statistically significant at the level of 1% and 5%, respectively. The effects of interaction between irrigation treatment and cultivar on total yield was significant at 5% probability level, and on non-marketable yield, marketable yield, and water use efficiency were significant at 1% probability level. The total yield in 8 experimental treatments under full irrigation conditions ranged from 30 to 39 t ha-1. In full irrigation conditions, Agria was the only cultivar that produced a significantly higher yield than other cultivars. Among the non-resistant cultivars, Atousa and Anousha cultivars experienced a greater yield decline of 40% and 39%, respectively, than Agria and Marfona cultivars. In drought stress conditions, two resistant cultivars, Atousa and Anousha, had the highest yield compared to other cultivars and the lowest yield compared to adequate water supply conditions (only 8.5% yield loss). Drought-resistant Atousa and Anousha cultivars with water use efficiency of 7.1 and 7.6 kg m-3, respectively, compared to the non-stress condition (6.1 and 6.2 kg m-3, respectively) had significant superiority.

The results indicated that not only drought tolerance is different in different potato cultivars but also stress memory is different in different cultivars. The use of tubers that have been exposed to drought stress (drought tolerant) during previous growth stages can affect plant behavior in the current growth. According to the results, it seems that in some cultivars, "stress memory" can be used to moderate the effects of stress in subsequent cultures.

The present study was carried out to identify sunflower tolerant genotypes at Research Station of Dryland Agricultural Research Institute (Sararood) in Kermanshah. The experiment was carried out in the form of a lattice square design. In this study, 64 sunflower genotypes with 8x8 arrangements were compared in two conditions of non-stress and applying water stress (irrigation cut off at flowering stage). The results showed that between genotypes as well as water stress treatment levels, there was no significant difference in number of heads per area. For head diameter in water stress conditions, in 27 genotypes head diameter was more than 11.4 cm and in 16 genotypes, head diameter did not reach even 10 cm. In non-stress conditions, Sil-96 genotype was shown the highest number of seeds per head by producing more than 842 seeds per head. However, 12 other genotypes were placed in a statistical group with this genotype. By applying water stress in 11 genotypes (including the Sil-96), the number of seeds per head was more than 630 and in 16 genotypes, the number of seeds per head was less than 400. In terms of weight of 1000 seeds, there was no significant difference between sunflower genotypes in both conditions of non-stress and water stress application. But by comparing two conditions of stress and non-stress, it was found that water stress caused a significant reduction in the weight of 1000 seeds in amount of 8.62%. Sil-96 genotype showed the highest seed yield in both stress and non-stress conditions. Although in each of the conditions of the water treatment, were placed into a statistical group with four other genotypes. Also, Sil-96 genotype had the highest stress tolerance index. Therefore, it seems that this genotype is recommended for cultivation in both stress and non-stress conditions.

Plants encounter biological and non-biological stress at different stages of their development. In this regard, drought stress is the most important non-seismic factor that, with global warming and the increased likelihood of drought, it is anticipated that by 2050, the performance of agricultural products in 50 percent of the world's agricultural land would be at serious risk. This will lead to a significant reduction in the production of food products. The dry and semi-arid climate of the country has become inevitable the cultivation and production of crops under the conditions of environmental stresses (drought, salinity and heat).Crops are show different reactions against these stresses. The occurrence of any of the stresses, or a combination of them, leads to a reduction in production. Sugar beet is one of the plants that tolerates these stresses. The aim of this research was to evaluate the tolerance of sugar beet test cross hybrids under non-stress and water deficit stress conditions in Khorasan Razavi province in order to select promising and drought tolerant hybrids.

This experiment was conducted to evaluate the drought tolerance of sugar beet test cross hybrids (57 hybrids) with seven controls including IR7, Mandarin, Jolgeh, Paya, Fotora, SC (7112*SB36) and origin population) in Khorasan Razavi Agricultural and Natural Resources Research and Education Center in two separate experiments under field conditions with unbalanced lattice design (8*8) with four replications in 2016. Irrigation was done routinely up to the thinning. Subsequent irrigations were done after 90 mm and 200 mm evaporation from the class A evaporation pan in non-stress and water deficit stress conditions, respectively. In this research, traits such as root yield, sugar content, sugar yield, Na, K, N, alkalinity, molasses sugar, white sugar content, white sugar yield and extraction coefficient of sugar were measured. Analysis of variance, estimation of correlations and step wise regression were performed with SAS 9.1 software and also path analysis was done using Amos v19 software.

Combined analysis of variance showed that there was a significant difference (p≤0.01) among studied genotypes and different irrigation regimes for all traits. The highest white sugar yield in non-stress and water deficit stress conditions were observed in (7112 * SB36) * S1 – 73 (13.34 ton / ha) and Mandarin (9.37 ton / ha), respectively. Correlation analysis revealed that the relationship between white sugar yield with root yield, sugar content, sugar yield, white sugar content and extraction coefficient of sugar was significantly positive in two conditions, while its correlation with Na, K, alkalinity and molasses sugar was significantly negative. According to the results of the stepwise regression analysis, more than 99 percent of white sugar yield variation was explained by sugar yield, extraction coefficient of sugar, root yield and sugar content in non-stress and drought stress conditions.

In general, the results showed that the genotypes 61 (Mandarin), 60 (IR7), 63 (Fotora), 51 (7112 * SB36) * S1 – 73), 40 (7112 * SB36) * S1 - 66) and 56 (7112 * SB36) * S1 - 72), which were superior in terms of stress tolerance index (STI) and also in terms of yield traits in stress condition, were introduced as the most drought tolerant genotypes.

Water deficiency causes crop yield loss, especially in flowering and pollination stage. This investigation was conducted out as a field experiment in Agriculture Faculty of University of Mohaghegh Ardabili in 2018, to evaluate drought tolerance of ecotypes at flowering stage. All plots were arranged in split plots based on a randomized complete block design with three replications. The main factor of experiment included two irrigation levels (full irrigation and irrigation until flowering stage) and sub-factor consisted of 10 different ecotypes of black cumin. Analysis of variance showed that the effect of drought stress on all studied traits except flowering date was significant. Drought stress significantly reduced the mean of all traits except flowering date and oil percentage. Comparison of mean data showed that the highest grain yield and oil content were observed in Semirom and Kazemain ecotypes, respectively. Also, the highest 1000-grain weight was obtained and in Ardestan and Khomeini Shahr ecotypes at full irrigation. Based on the results of cluster analysis under drought stress condition, the studied ecotypes were divided into three groups. Ecotypes of third group including Khomeini Shahr, Semirom, Isfahan, Ardestan and Shahreza had higher yield and yield components than ecotypes in other groups. Therefore, these ecotypes were identified as high yielding and drought tolerant. Also, three-dimensional plots based on stress tolerance index (STI), yield stability index (YSI), yield under full irrigation (Yp) and end-season drought stress (Ys) showed that the ecotypes of Khomeini Shahr, Semirom, Isfahan, Shahreza and Ardestan are considered as superior ecotypes in both conditions.

Coriander is an annual herb of the umbel family and is belonged from North Africa to south-western of Asia. Coriander is one of the important medicinal plant that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely employed as a condiment, especially for flavoring of sauces, meat products and bakery and confectionery items. Also, coriander fruits are as a source of essential oils and fatty oil. Water deficit stress is one of the most important factors limiting the growth and survival of plants in arid and semi-arid regions of the world. Water is a major component of the fresh produce and significantly effects on weight and quality of plants. Also, water deficit may cause significant changes in the yield and composition of essential oils in aromatic and medicine plants. So that, was reported that water deficit increased essential oil percentage in coriander but decreased essential oil yield. Iran with an average annual rainfall of 240 mm is included among arid and semi-arid regions of the world. Of the million hectares of cultivated region, only five millions are under irrigation because of intense water limitations. However, Iran is one of the world’s commercial coriander producers. Coriander has been cultivated for many years in different parts of Iran. Therefore, development of drought-tolerant cultivars with high essential oil yield is important in coriander. This research was conducted in order to evaluate the effect of drought stress on morphological, physiological and phytochemical characteristics of endemic coriander genotypes. F2 generations derived from half-diallel crosses of six endemic coriander genotypes including Isfahan, Hamedan, Bushehr, Mazandaran, Markazi and Alborz, together with their parents were evaluated in randomized complete block design with three replications in each experiment during growing season of 2016 in the research field of Tarbiat Modares University. Plants were treated with different levels of water treatment: well watered (WW), moderate water stress (MWS) and severe water stress (SWS). Data were collected on plant height, leaf number, branch number per plant, umbel number per plant, fertile umbel number per plant, fruit number per plant, thousand fruit weight, fruit yield, biological yield, essential oil content, SPAD chlorophyll content, relative water content and electrolyte leakage. The results of ANOVA and comparison of means indicated that the effect of drought stress was significant for all the studied characteristics. The results showed that by increasing drought stress the most studied traits decreased but the essential oil content significantly increased. The highest essential oil content was observed in moderate stress. Studies have, however, indicated that water stress have a number of positive effects on the biosynthesis of secondary metabolites such as essential oil content. Because in case of stress, more metabolites are produce in the plants and substances prevent from oxidization in the cells, but essential oil yield reduce under drought stress. This may because of the relationship between the amount of the essential oil and fruit yield that by progress in drought stress, increase in essential oil but decrease in fruit yield therefore essential oil yield is reduced. Also in the study was used of stress tolerance index (STI) as the best indicators for evaluating of tolerant to drought stress of coriander genotypes. The Mazandaran genotype and crosses derived from this genptype (Alborz Mazandaran, Markazi Mazandaran, Isfahan Mazandaran, Mazandaran Hamadan and Mazandaran Bushehr) were identified as drought tolerant genotypes. Generally, the results indicated that drought stress decreased all studied traits. Whereas essential oil content was increased under drought stress conditions. Also, The Mazandaran genotype and crosses derived from this genptype (Alborz Mazandaran, Markazi Mazandaran, Isfahan Mazandaran, Mazandaran Hamadan and Mazandaran Bushehr) as drought tolerant genotypes can be considered as donor parent which contains drought tolerance genes and could be used to improve coriander high essential oil yield in drought condition.
Acknowledgements: The authors thank from the Gene bank of the Seed and Plant Improvement Institute of Karaj, Iran for making available plant materials.

In arid and semi-arid regions of the world including Iran, soil salinity is one of the major abiotic stresses. One of the ways to achieve high performance in these areas is using salt tolerant varieties. Also, study on relationships between yield and its components will improve the efficiency of a breeding program with appropriate selection criteria. In this study, 110 bread wheat genotypes were evaluated in two conditions (non-stress and saline stress) at the research field of the National Salinity Research Center (NSRC). The salinity of water used in irrigation in saline and non-stress conditions was 10 and 2 dS.m-1 respectively. In this study was used of stress tolerance index (STI) as the best indicators for evaluating of tolerant to salinity stress of bread wheat genotypes. Based on stress tolerance index (STI)and seed yield in non-stress and saline stress conditions, the linesSalt18, Salt19, Salt20, Salt21, Salt22, Salt23, Salt24, Salt25, Salt26, Salt27, Salt28, Salt29, Salt30, and varieties Arg, Bam, Rushan, Sorkhtokhm, BumiYazd, Kavir, Moghan 1, Sardari, Sharyar, Shirazhad had a high yield in the non-stress and saline stress conditions and these genotypes were selected as the most tolerant genotypes to salinity.The highest grain yield under non-stress and saline stress conditions was produced by Salt29 line (178.13 gr) and Salt24 line (164.33 gr), respectively which had more grain yield than control cultivars (Arg, Bam, Rushan, Sorkhtokhm, Bumi Yazd and Karchia). Also, based on the results of sequential path analysis, kernel weight per spike and number of fertile tillers in non-stress conditions and spike weight, number of fertile tillers, days to headingand peduncle weightin saline stress conditions were selected as first order variables.Therefore, it seems that these traits could be used as a suitable criterion in wheat breeding programs for increased seed yield in both non-stress and salinity stress conditions.

In order to evaluate the effect of potassium sulfate nutrition on chlorophyll contentand drought tolerance indexon Mungbean genotypes in the north of Khuzestan Province, this study was conducted in split plot factorial in a randomized complete block design with three replications in 1390 and 1391 at the agricultural Research center south of west Country (Safiabad). The main plot was irrigation after 120, 180 and 240 mm evaporation from pan evaporation (respectively marked I120, I180 and I240),and the subplots were potassium fertilizers with 0, 37.5 and 75 kg K2O per hectarfrom potassium sulfate(respectively marked F0,F1 and F2) and genotypes (Parto, Hindi and VC6173, Cn95 and KPS1lines ) in a factorial arrangement.The results showed that grain yield in I180 and I240 treatments, reduced 21.8 and 30.4 percent respectively in comparison with control treatment(I120).the highest and lowest tolerance to drought stress were allocated to Hindi (0.83) and KPS1 (0.47) respectively. Potassium application at the rate of 75 kg/ha in I240 treatment, increased drought tolerance in all genotypes except KPS1. chlorophyllcontent was influenced irrigation regimes, irrigation and genotype, irrigation-fertilizer as well as the interaction of three factors at the of 1% and fertilizer and genotypes at the level of 5%.The overall results showed that Hindi due to high drought tolerance and VC6173 due to shoot standing and high drought tolerance were superior to other varities.

Cold is one of the most important abiotic stresses, limiting growth and yield of rapeseed in cold prone areas in Iran. In order to study the cold tolerance of selected popular rapeseed genotypes in Iran and its relationship with SSR markers, this research was conducted in two separate experiments. In the first experiment 24 genotypes of rapeseed were exposed to 25˚C (as control) and 5˚C (as cold stress) treatments at seedling stage. Ten days after implementing cold treatment (about 30 days after sowing), an array of morphological and physiological characteristics were measured. A wide genetic variation was observed among genotypes for the measured traits. The maximum of the genetic diversities of morphological characters in cold and non-stress conditions  (60.77 and 62.22, respectively) was observed for the root dry weight. Cluster analysis classified genotypes into four groups based on the measured characters and CR3198 was the genotype identified as cold tolerant at seedling stage. This genotype indicated the greatest root length (18.25 cm), root dry weight (0.3 g), SPAD value (39.71) and Fv/Fm (0.79) and the smallest electrolyte leakage (13.02) under cold stress (5˚C) treatment. Cold tolerant genotypes were characterized by a high seedling vigor. In the second experiment relationships between ten pairs of SSR markers and cold-related traits were investigated. Results of binary logistic regression showed that some SSR markers were associated with shoot and root dry weight and cold stress tolerance index. Three SSR markers including Na10-B08, Na12-E09 and Ra2-E11 were found to be related to cold stress tolerance index of rapeseed at seedling stage. In general, results of this investigation can be used for improving cold tolerance of rapeseed seedlings in breeding programs.

IntroductionLegumes such as Pinto Bean (Phaseolus vulgaris L.), in addition to the value of food and proteins production, they are able to fix biological nitrogen and therefore, are desirable for planting in sustainable agricultural systems in order to strengthen and preserve soil fertility. Low input farming systems (LIFS), which are a part of sustainable agricultural systems was defined as a way to optimize the use of ecological inputs and to minimize the use of inputs such as chemical fertilizers and pesticides in every time and every place to reduce the cost of production, reduce pollution of groundwater and surface water, reduce of pesticide residues in food, reduce total risk in agriculture and an increase in short and long term profitability of agriculture. Evaluation and identification of the suitable cropping plant cultivars for planting in low-input agricultural systems has begun three decades ago, in the world. The aim of this study was to identify of pinto bean genotypes suitable for cultivation in low input crop management system and use them in breeding programs and the cultivar release process of this crop.
Material & MethodsIn order to evaluate Pinto bean genotypes (Phaseolus vulgaris L.) in terms of response to low input crop management, 559 Pinto bean genotypes were evaluated using augmented design in both conventional, and low-input crop management conditions. According to grain yield of genotypes in the two conditions, MP, GMP, TOL, STI and SSI were calculated and then, the correlation between the index and the main component analysis was performed. All Statistical analysis, correlation estimates, factor analysis and graphs performed using SPSS software.
Results & DiscussionAccording to correlation between grain yield in optimal and low input conditions (r=0.34**, n=559), it was found that genotype selection based on grain yield in both conditions can identify genotypes with high yield and stable production. The correlation between grain yield in conventional condition and MP, GMP, STI, SSI and TOL was positive and significant. In addition, the grain yield in low input condition had a positive significant correlation with GMP, MP and STI. Negative significant correlation was shown between grain yield in low input condition and SSI and TOL. According to cluster analysis, the bean genotypes were placed in 5 cluster that genotypes in cluster 2, in term of GMP and STI were 76% and 181% higher than overall average and in term of SSI and TOL were 60% and 48.5% lower than overall average, respectively. Therefore, they were selected as the best genotypes for cultivation in low input conditions. Based on the main component analysis on five indexes and YP and YS in evaluated genotypes, it was observed that two main component explained 97.8 percent of the total variation. The first and two principle components explained 61.8% and 35.9% of total variation, respectively. The highest positive factor in the linear combination of the first component was related to Yp, YS, MP, GMP and STI. Therefore, this component was called as yield component and tolerance to low input conditions. Because of high levels of these indicators are favorable, due to the positive and high values of these component, to select genotypes were acted that have a higher grain yield in both conventional and low input conditions. The highest positive factor in the linear combination of second component was related to SSI, TOL and a little Yp and the highest negative factor was related to Ys. So this component was called as sensitive to low input conditions. The genotypes that had lower values of second component had the least sensitive to low input conditions. According to biplot of two main components, genotypes were classified into four groups. Genotypes that were in the A zone, in terms of the tolerance index to low input conditions (MP, GMP and STI) have higher values than average and in terms of the sensitivity index to low input conditions (SSI) have lower values than average so they were most suitable genotypes.
ConclusionAccording to grain yield and tolerance indexes to low in put condition, the group 1 genotypes (Ks-21184, Ks-92021, Ks-21119, Ks-21280, Ks-21461, Ks-21362, Ks-92198, Ks-21671, Ks-21673 and Ks-21236) as the best genotypes for cultivation in low input farming systems (LIFS) were identified and selected.

Increasing consumer demand for medicinal plants needs to develop agro-management and planning correctly. Black cumin is one of the important and valuable medicinal plants and, due to its frequent application in the pharmaceutical industry, is cultivated in different parts of Iran but, limiting environmental factors have a negative impact on its growth and production. Drought is one of the main inhibitors for crop production in Iran and many arid and semi-arid regions. Production and potential yield of black cumin also can affect by drought stress. There are not many reports available about drought tolerance of black cumin. Therefore, this research focused on response of 10 black cumin genotypes to water-stress condition.
In order to study the effects of drought stress on morpho-physiological traits including oil and grain yield of black cumin an investigation was carried out in Abadeh (city of Fars province) in 2014. The experimental design was split plot based on complete randomized block design with three replications. Water-stress and well-water conditions as main factor and 10 black cumin genotypes were used as sub-factor. Application of drought stress was seedling to ripening stages. Plant height, number of lateral branches, number of follicles per plant, number of seeds per follicle, number of seeds per plant, 1000 grain weight, grain yield, oil content, oil yield, proline content, total soluble sugars and potassium content of black cumin genotypes were measured in both stress and non-stress conditions. Descriptive statistic parameters for all the above measured traits and stress tolerance index (STI) for oil and grain yield were calculated. Data subjected to analysis of variance and means comparison using SAS and Excel soft wares.
Analysis of variance showed that the effect of drought stress for all the measured traits, genotype effect for the most of traits except for the number of follicles per plant, grain yield, oil content percentage, proline and total soluble sugars contents, and interaction between drought and genotype for all traits except for grain yield, oil yield, and proline content were significant. Arak genotype had the highest values for plant height, seed number per follicle, number of seeds per plant and potassium content in water-stress condition. Classification of genotypes using three-dimensional plots of stress tolerance index, stress and non-stress oil and grain yields showed that Arak and Indian were tolerant genotypes for grain and oil yields respectively. Stress intensity results indicated that proline content and number of lateral branches (SI=0.59) more affected by drought stress.
Morpho-physiological traits of black cumin affected by drought stress. There is enough genetic diversity for drought tolerance among black cumin genotypes. So, based on these results improvement of drought tolerance of black cumin is possible. These results can be used in breeding programs to improving drought tolerance of black cumin.

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.

In order to evaluate water stress tolerance-related traits and their relationships in barley genotypes, as well as identification of drought tolerant genotypes, a field experiment was carried out during 2012-13 and 2013-14 growing seasons in College of Agriculture, Shiraz University, Iran. Seventy four foreign barley genotypes and two Iranian varieties (Reyhan and Nosrat) were evaluated under normal irrigation and water stress (water withheld at flowering stage) conditions according to a split plot experiment based on a randomized complete block design. Correlation analysis indicated that stress tolerance index (STI) was the best criterion for selecting barley drought-tolerant genotypes and significant correlations between number of fertile spikes, spike length, biomass, and seed yield and stress tolerance index were observed. Based on STI, the genotypes number 17, 23, 24, 41, 47, 58, 65, 71 and 72 were proved to be the most tolerant and high-yielding genotypes under both normal and water stress conditions.