پژوهشنامه اصلاح گیاهان زراعی
پیاپی 37 (بهار 1400)

One of the most important medicinal plants of Iran, Poneh belongs to the mint family. Due to the numerous and very useful medicinal properties of oregano, this plant has attracted many studies. In this study 11 different ecotypes of Mentha longifolia belonging to 11 different regions of Iran including West Azarbaijan, Yazd, Gilan, Chaharmahal Bakhtiari, Khuzestan, Lorestan, Kerman, Hormozgan, Khorasan, Qazvin and Ardabil were studied. In order to investigation genetics variety between pennyroyal ecotypes in Mohaghegh Ardebili University, an experiment was implemented in framework of complete random block in 11 ecotypes (treatments) and 3 repeats. DNA was extracted and evaluated using 23 different ISSR primers to evaluate the genetic diversity among ecotypes. The results indicated sufficient polymorphism among these ecotypes. A total of 60 clear and scalable bands were produced, 60 of which are polymorphic. In p9 and p8 markers based on Shannon’s genetics variety, Ni‘s gene variety and multiple-shaped content had the most highest and lowest values between cases respectively. Also two mentioned markers had most highest and lowest values for effective alleles number. According to Shannon’s and Ni’s markers, Kerman and Yazd population had most highest and lowest values for mentioned two features. Also, based on Ni’s genetic distance; genetics distance between ecotypes is variable from 0.285 in Kerman and Qazvin to 0.672 in Hormozghan and Kerman and 0.625 in Yazd and Qazvin.  Grouping is done based on ISSR markers similarity matrix and ecotypes were classified in 3 cases. In PCA, 2 primitive components describe more than 56% of variance. Existence of genetics variety between pennyroyal ecotypes for goals selection possibility.

Cadmium is an important pollutant of heavy metals, which is very toxic to plants and animals. Rice is the most popular food among Iranians and the presence of heavy metals in trace level in rice has received special attention because they are directly related to health. In order to evaluate the tolerance of rice genotypes to cadmium, 40 rice genotypes under hydroponic conditions were used for seedling tolerance and absorption of cadmium in different levels of stress (control, 100, 200 and 300 μm cadmium) and in a split plot experiment in a completely randomized design template was examined. The results showed a significant difference between genotypes. In terms of cadmium adsorption, genotypes of Mirtarom, Sangtarom, F12L49-3، 229R and KOSHIHIKARI had the lowest cadmium adsorption. Principal components analysis based on the traits evaluated for cadmium show 70.160, 70.357, 72.641 and 66.305 percent of the changes by the first and second components, respectively, at the control levels of 100, 200 and 300 micromolar of cadmium. Cluster analysis based on the studied traits at control, 100, 200 and 300 micromolar of cadmium classified the genotypes in two, five, three and two clusters, respectively. In sum, genotypes of Sangtarom, Mirtarom, F12L49-3, 229R and KOSHIHIKARI as genotypes tolerant to cadmium and genotypes of M30, ARIAS HALUS and Kinan Dang Patong as genotypes classified as Noncompliant were determined according to biplot analysis and cluster analysis. The generations obtained from crossing between tolerant and susceptible cultivars could be used as segregating population in genetic and molecular studies.

Drought stress limits zinc absorption by cereal plant because of reduction of root growth and development as well as declining zinc movement in soil. On the other hand, tolerance to drought needs enough available zinc for plant to well regulate expression of genes that are responsible for cell protection against drought stress. Moreover, zinc deficient plants unable to detoxify reactive oxygen species (ROS) under drought stress conditions. Hence, zinc deficiency along with drought lessen grain yield and its nutritional quality, which cause hidden hunger in billions people worldwide. Although, zinc fertilizers can solve the problem, but it is not a sustainable solution in drylands because of soil surface dryness, zinc fixation in clay soils, and fertilizer unavailability. Along with zinc fertilizers, cultivation of zinc efficient varieties will be a complementary and viable solution in drylands. Hence, breeding zinc efficient cereals is a sustainable and necessary method to improve grain yield and nutritional quality of people food in 2025. Zinc deficiency in crops is the most widespread micronutrient deficiency, with about 50% of the cereal-growing area worldwide containing low levels of plant-available Zn. Zinc deficiency in soils reduces yield and nutritional quality of cereal (e.g. wheat) and afflicts 1 billion people especially in many developing countries like Iran. Sustainable solutions can only be developed through agricultural system approaches such as plant breeding. Micronutrient enrichment traits are available within wheat genomes that could allow for substantial increases in Fe, Zn and without negatively impacting protein and yield. There is considerable genotypic variation both within and between cereals for micronutrient efficiency. A number of studies have demonstrated differential Zn efficiency in barley, suggesting that genotypic variation could be exploited in breeding programs to produce genotypes with higher Zn efficiency. Various mechanisms may explain Zn efficiency in crops, including increased Zn uptake, increased Zn availability in the rhizosphere due to release of root exudates, and more efficient internal Zn use. In wheat and barley, Zn-uptake capacity of roots is one of the mechanisms of Zn efficiency. Drought stress and zinc (Zn) deficiency are serious abiotic stress factors limiting crop production in drylands of Iran, but the interaction between Zn deficiency and drought stress has not been studied extensively. Zinc nutritional status of plants may affect the drought sensitivity of plants in different ways. Zinc-deficient plants use water less efficiently and are less able to respond to increasing soil water deficits by osmotic adjustment than plants that are supplied with adequate levels of Zn. Moreover, drought stress kills plants by inducing production of reactive oxygen species (ROS). An adequate Zn nutrition can be involved in detoxification of ROS, and it is also important for reducing the production of free radicals. Therefore, likely that drought stress-related yield loss is additionally accentuated when plants would simultaneously suffer from Zn-deficiency stress. On the other hand, the review of literature indicates that application of Zn fertilizers has a potential to increase availability of Zn to plants, which will result in enhanced drought tolerance.

Ajowan (Trachyspermum copticum L.) is one of the most important herbs of the Apiaceae family in semi-arid tropical regions of Iran, which is considerable in the production of essential oils with valuable secondary metabolites, especially thymol. In order to determine the secondary metabolites profile of ajowan under drought stress, a split plots experiment was conducted in two irrigation conditions (normal and drought stress) as main factor and 36 ecotypes of ajowan belong to 9 different provinces of Iran as sub plots were planted based on a randomized complete block design with 3 replications during 2015 and 2016 in Agricultural Jahad Research Station of Kerman. Based on the results of combine analysis, water stress has significant effect on the components of essential oil. Gas chromatography–mass spectrometry (GC–MS) analysis revealed the presence of 13 compounds with the major constituents including thymol, p-cymene and γ-terpinene constituents in all ecotypes in both irrigation conditions. Based on bi-plot, two groups of high thymol and high p-cymene were identified. In this experiment, increasing the irrigation interval effected as an advantageous strategy to improve pharmacological component in some ecotypes. In conclusion, Zabol ecotype was superior to others, in terms of its relatively good performance of thymol, special in drought stress and it is recommended as suitable ecotype for cultivating in dryland and also where drought stress usually happens at the end of cropping season. Also, two ecotypes included Zabol and Mohammadieh were identified as extreme ecotypes in response to drought stress in reproductive stage, these ecotypes could be recommended for breeding programs to obtain drought tolerant thymol-chemotype cultivars ajowan.

Drought is one of the most important stresses that inhibit growth of plants and due to mainly disturbance of the balance between the production of reactive oxygen species and antioxidant defense, causes oxidative stress and different biochemical and physiological responses in plants. So, the evaluation of plants for drought tolerance to cultivate in dry regions is very important.In this way, the present study aimed to investigate and compare two native barley cultivars of Sistan region (Nimroz and Nomar) based on measurement of some defense mechanisms and physiological properties including Antioxidant enzymes activity (Catalase (CAT), Ascorbate Peroxidase (APX), Polyphenol oxidase (PPO)) photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoids), protein content, relative leaf water content (RWC) and some Osmotic regulators (proline and carbohydrate) were under drought stress. This experiment was performed as a factorial in a completely randomized design with three replications, conducted at the Institute for Biotechnological Research in the University of Zabol. Experimental treatments included drought stress (50%, 75% and 100% of the field capacity (control)) and two cultivars native to Sistan region (Nimroz and Nomar). Analysis of variance showed that the effect of cultivar, drought stress and interaction of cultivar and drought stress were significant at 1% probability levels, on all studied traits. Results indicated that with increasing drought stress levels compared to normal levels, the amount of photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoids), protein content and relative leaf water content (RWC) decreased. However, proline and carbohydrate concentration, carotenoid content, the activity of antioxidant enzymes CAT, PPO and APX were increased. Based on the results of the interaction, it was identified that Nimroz cultivar had a better reaction than Nomar cultivar in terms of protein, relative leaf water content, carotenoids, osmotic regulators and antioxidant enzymes (catalase and ascorbate peroxidase) during drought stress. While the Nomar cultivar was the highest average in terms of chlorophyll a, chlorophyll b, total chlorophyll, protein and enzyme polyphenol oxidase compared to the Nimroz cultivar during drought stress.

Triticum turgidum var. tetraploid durum and has 28 chromosomes and one of the worldchr('39')s most important crops in semi-arid regions of the world are grown. Introduced genotypes with greater yield, drought tolerance and high stability are one of the necessities of cultivation of durum wheat. Genotype interaction in the environment is one of the important issues in breeding programs and if there is an interaction, the stability and compatibility of genotypes in different environments should be evaluated to produce a safe product. In the present study, in order to investigate the stability of 10 durum wheat genotypes, an experiment was conducted in the form of a randomized complete block design with 3 replications in both rained and end irrigation conditions during the cropping years 2019-2018 and 2020-2019, in Koohdasht, Lorestan province. The results of analysis of variance of grain yield of genotypes for the experiment during two years in two environments showed that there was a significant variation (p <0.01) for yield between genotypes, the effect of the year was not significant and the effect of the two environments was significant at 1%. Also, the interaction of genotype × environment was significant at 1% level. Based on the average yield, Omrbi3, Hana, Behrang and Aria had the most stability, but in contrast to Dm-73-13, Dehdasht, Maragheh 1 and Maragheh 2 showed the least stability. Stability of genotypes was investigated by parametric and non-parametric methods based on grain yield. The results showed that none of the parameters had a positive and significant correlation with yield, so the genotypes with the highest yield based on these parameters did not have high stability. Based on parametric methods, Aria and Shebrang genotypes had the highest stability and moderate yield. In nonparametric methods, it was observed that Aria, Hannah and Omrbi3 genotypes, which had high potential for yield based on RS and kr, also showed high stability.
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Comparative identification of relations among yield components under stress and normal situation can provide novel breeding strategies to plant breeders. Sesame is an oil crop with high quantity and quality of edible oil, suitable for human food. In this study, effects of limiting in avalibility of water to 15 sesame genotypes from germplasm collection of Oil Seed Crop Res. Dep on yields components was investigated. Regression analysis of seed yield on various phonologic and yield components revealed significant effects of fertile axillary branch and number of seed per capsule under normal condition and merely fertile axillary branch under water limiting situation. Comparative factor analysis between normal and water limiting conditions revealed shifting in the priority of photosynthate allocating to various organs and sinks upon water limitation. Nevertheless, axillary branches constitute the first and primary target for allocating assimilates under both normal and water limiting conditions. Under water limiting condition, plant focuses itchr('39')s most strong and primary control system on number of axillary branches, followed by two successive less important and less strong control systems, which affect on seed weight, a parameter that determines plant maintenance in the nature and guarantee survival of the next generations. Focusing on the biologic behavior and relations among the behaviorchr('39')s components on one hand, and shifting from biometrical point of view to biometrical-physiological concepts will increase efficiency of stress breeding programs.

In order to grouping 19 populations fennel from the agronomic and morphological traits, an experiment was conducted in randomized complete block design with three replications under limited and favorable condition of irrigation at the Agricultural Research Station, University of Tabriz. Combined analysis of variance showed that the effects of different irrigation conditions, population and population × environment interaction was significant for most of the studied traits; That was representing a significant difference between the fennel studied populations and also showed populations different reactions under different of irrigation condition. Also, under limited condition of irrigation, the number of umbel per plant, the number of seed per umbel, 1000-seed weight, grain yield, essential oil yield for all studied populations were significantly reduced. However, all studied populations were associated with a significant increase in essential oil under limited condition of irrigation. Correlation of grain yield with essential oil yield (0/949), the number of umbel per plant (0/696), the number of seed per umbel (0/469), plant height (0/641), tillers(0/617) and biomass(0/891) was significant positively under water deficit stress condition. This indicates the traits had the greatest effect on grain yield under water deficit stress condition. In favorable conditions of irrigation, the studied populations were divided into three groups for all traits. Bonab and Birjand populations were in the best group the evaluated traits including grain and essential oil yields. In terms of water stress, the studied populations were divided into three groups for all traits. The best groups the all evaluated traits included Garineh, German (11486), German (1182), Hamadan and Bonab populations. Grouping populations based on drought tolerance indices showed that Bonab, Birjand, German (11486) and Hamadan populations are superior from the drought tolerance than other evaluated populations.

This study aimed to evaluate the effect of different types and concentrations of plant growth regulators in MS medium on callus formation and regeneration of different explants of medicinal plant Galega officinalis. To callus induction, leaf, root, hypocotyl, and stem nodes explants were cultured on MS medium containing different concentrations of 2,4-D (0.5, 1, 3, and 5 mg/l) in combination with BAP (0, 0.5, 1 and 3 mg/l) or Kin (0, 0.5, 1, and 3 mg/l). It was observed that 2,4-D in combination with Kin was very effective and in most of the used concentrations, it resulted in 100% callus induction. Among them the 5:0.5 mg/l concentration of 2,4-D:Kin in the nodal stem explant showed the highest callus growth with an average of 1450 mg fresh callus weight. In order to direct regeneration, leaf, cotyledon, and stem nodes were cultured in MS medium containing different concentrations of BAP and Kin in combination with NAA, while regeneration was observed only in the stem nodes. The highest regeneration rate was related to 0.25:0.1 mg/l in both BAP: NAA and Kin:NAA with an average of 93.33%. The highest amount of induced shoots (with an average of 2.86 shoots in each explant) and the highest shoot length (5.6 cm) were observed at 2:0.5 and 2:0.1 mg/l of BAP:NAA, respectively. The shoots obtained from the regeneration experiment were transferred to MS medium containing different levels of NAA and IAA for rooting. The results of mean comparisons showed that 0.25 or 0.5 mg/l of NAA or IAA resulted in the highest percentage of rooting with an average of about 90%. The highest number of roots was related to explants cultured in 0.25 mg/l of both NAA and IAA growth regulators (with an average of 4 roots per explant) and also, the highest root length was observed in explants cultured in 0.25 mg/l of IAA (with an average of 6.5 cm). At all, in this study, the most appropriate combination of plant growth regulators and explant for callus induction and direct regeneration of G. officinalis was introduced, which can be useful in future biotechnological studies of this medicinal plant.

Forty selected soybean (Glycine max L. Merr) in the form of a randomized complete block design with three replications under normal irrigation and stress conditions in two separate locations, in the research farm of Karaj Seedling and Seed Breeding Research Institute in 2015-2015 crop year Was examined.Based on performance under non-stress (Yp) and stress (Ys) conditions, quantitative indices of drought tolerance, tolerance index (TOL), geometric mean (GMP), stress tolerance (STI), stress sensitivity (SSI), dry sensitivity (SDI), stress sensitivity percentage (SSPI), harmonic mean (HARM), stability Yield (YSI), relative dryness (RDI), were calculated. The results of analysis of variance showed a significant difference in genotypes in terms of yield per hectare under normal conditions at 5% probability level and a significant difference at 1% probability level of genotypes under water stress conditions. The results of mean comparison showed that the highest mean yield in irrigated and rainfed conditions belonged to 19 and 34 genotypes, respectively. The lowest values ​​of tolerance index, stress sensitivity, stress sensitivity percentage, drought sensitivity, belong to cultivars 7, 10, 7, 10, respectively, and the highest values ​​of geometric mean index, stress tolerance, performance stability, relative drought, harmonic mean, Belonged to the numbers 1,7,7,7,1, respectively. Correlation analysis of yield and drought tolerance indices in stress and non-stress environment showed that STI and GMP indices are the most suitable indices for selection top genotypes. Factor analysis also showed that the first two factors explain 98% (the first factor of 58.9% and the second factor of 39.3%) of the studied changes in stress and non-stress conditions. Based on biplot analysis based on the first and second main components, genotypes 1 and 34 are located in the region with high production potential and low sensitivity to stress, and biplot analysis justifies the selection of stress tolerant genotype based on GMP.STI ​​index.

The most important goal in all crop breeding programs is to increase yield, and yield improvement requires the use of efficient statistical methods to identify superior genotypes. In determining the superiority of genotype, in addition to high yield, yield stability in different environments must also be considered.Biplot analyses are good tools for selecting superior genotypes and to increase efficiency in selection. In this study, GGE biplot method was used to evaluate the stability of grain yield of 205 lines and lentil cultivar in augmented design during three cropping years in the Faculty of Agriculture of Zanjan University under rainfed conditions. The results of combined analysis of control cultivars showed that the effect of year and year × cultivars interaction were significant for grain yield. Thus, the lines were examined using GGE biplot graphic method. The results showed that the first component and second component explained 68.3 and 28.5 percent (in total 96.8 percent) of total variation respectively, which indicates the high validity of the bipod in the explain. The results also showed that lines 170 and 164 were the best lines in the first year and lines 157 and 183 were the best lines in the third year. Line 167, in addition to having high yield, had lower stable yield. This line was placed in the center of the circle as the ideal line and the lines 164, 170, 147, 122 and 7 were placed in the next ranks. Lines 147, 128, 7, 160, 51, 148, 156 and 160, in addition to having higher yield than the average, had a short distance from the stability axis and had low unstable yield. Lines 8, 57, 157, 86, 186, 83, 140, 164 and 170, despite having high performance, had high unstable yield. Biplat polygonal analysis led to the identification of two mega-environments, among which the first year had the most discriminating ability among the years. Existence of 90º angle between the first and second year showed no correlation between these two years and their conditions were different and greater than 90º angle of the second year with these years showed its negative correlation with the first and second year.

In order to investigate the effect of genotype, environment and the interaction of genotype × environment, for seed yield, 18 lentil genotypes in a randomized complete block design with three replications in four environments (Khorramabad, Gachsaran, Ilam and Gonbad) during three years (2014-2017) Were evaluated. Based on combined analysis of variance, the main effects of location, genotype and genotype × location and genotype × location × year interactions were significant. The results of combined analysis of variance for different environments showed that environment, genotype and genotype × environment interaction for Showed seed yield. According to the results of AMMI analysis of variance, the environment was the main source of change, which accounted for 83.6% of the total squares. The results of AMMI analysis of variance also showed that the four-component interaction effect on seed yield was significant. The first two main components of the AMMI model accounted for 52.56% of the total yield variance. The results of AMMI stability values (ASV) showed that for seed yield, the genotypes including G8, G7, G9, G18, G6, G16 and G17 had the lowest values and therefore the highest general stability to all experimental environments. Genotype G5 with ASV value of 33.7 was highest private stability to the second environment (E2). Among the genotypes with the lowest ASV, only G6 and G16 genotypes had higher average seed yield than the average of all genotypes. Based on the values of the first two principal components, AMMI (ASV) stability value and genotype stability index (GSI), the genotypes G6, G1 and G13 were identified as the most stable genotypes, and the closest genotypes to the ideal genotype.

An experiment was conducted in split plot based on randomized complete block design with three replicates in the greenhouse of Zar Gostar Arta Agricultural Company for 2 years in order to determine the tolerance of hybrids from combination of potato cultivars to different dehydration conditions in Ardebil province. The main factor included three levels of irrigation (100, 85 and 70% of plant water requirement) and the sub factor included 12 potato cultivars. The results showed that there was a significant difference between irrigation levels, genotypes and the interaction of irrigation levels on genotype in terms of tuber yield at 1 and 5% probability levels. In this study, under normal irrigation conditions, R12 (Luca × Esprit) had the highest average of tuber yield by (53.6 ton/ha) and S34 (Esprit × Agria) and had the lowest average of tuber yield by 28.9 ton / ha. S14 (Luca × Esprit) had the highest average of tuber yield by 40.3 and 35.5 (ton/ha) respectively, in the stress condition of 85 and 70% of usable water and S34 (Esprit × Agria) had the lowest average of tuber yield by 40.3 and 35.5 (ton/ha) respectively, under irrigation levels of 85 and 70% of usable water. There was a significant and positive correlation between tuber yield under normal irrigation condition (100% usable water) and mild and severe water dehydration stress (85 and 70% usable water) with MP, GMP, TOL and STI indicator. However, there was a negative and significant correlation between tuber yield and indicator of sensitivity to stress (SSI) under mild and severe stress conditions (85 and 70% of usable water). There was a positive and significant correlation between SSI index and TOL at 5% probability level. Factor coefficients in the studied traits for the studied treatments between quantitative and qualitative traits of hybrids obtained from potato cultivars composition showed that four factors explained 86.508% of total changes under normal stress conditions (85% of usable water) and S24 (Banba × Agria)، S14 (Luca × Esprit)، R24 (Banba × Agria)and S23 (Banba × Esprit) were more valuable than other hybrids in terms of effective traits on yield factor and structural factor.

Drought is the most important limiting factor for durum wheat production in the Mediterranean and other regions. Iran is located in arid and semi-arid parts of the word. In order to identify the most effective stress tolerance indices and the most tolerant durum wheat genotypes, this study was conducted as two separate experiments (one under normal irrigation conditions and the other cut off  irrigation after 50% spike) on 20 promising durum wheat lines in a randomized complete block design at three replications. The research was implemented at Neishabour Agricultural Research Station for two cropping seasons. Stress tolerance indices were calculated using the two-year average yield, which were MP, GMP, STI, SSI, TOL, YI, YSI, RDI, DI, MRP and REI. Biplot correlation equations could explain relation between grain yield and calculated indices where GMP, MP and STI were the best ones under both conditions. Lines 7 and 8 were identified as superior genotypes based on GGEBiplot polygon. Keeping in view both yield and stability adopting GGEBiplot, line 7 was favorable. Also Line 7 was ideal genotype in relevant biplot. Generally, results showed that GGEBiplot was suitable methods for identifying superior genotypes based on biplot indices considering both yield and stability.

Study on relationships between yield and other agronomic traits will improve the efficiency of a breeding program with appropriate selection criteria. In this regard, 24 new sunflower hybrids along with Golsa cultivar were evaluated in a simple lattice design with two replications in agriculture research station of Gorgan during 2020 cropping season. The results indicated that the highest coefficient correlation was obtained between head diameter and thousand seed weight with seed yield. Sequential stepwise multiple regression analysis was performed to organize the predictor variables into first, second and third order paths based on their respective contributions to the total variation of yield and minimum collinearity. Based on the variance inflation factor and magnitude of direct effects, seed number per plant, thousand seed weight and stem diameter were considered as first order variables and accounted for 70 percent of total variation of seed yield. The t-test of significance, using standard error values, obtained through bootstrap resampling, indicating that all direct effects were significant. Generally, the results indicated three traits of seed number per plant, thousand seed weight and stem diameter could be considered as selection criterion in selecting for increased yield in sunflower. Also, the results indicated that among studied genotypes, genotypes No. 2, 4, 5, 10, 11, 19 and 22 were recognized as superior genotypes regarding seed yield and traits related to yield.

To evaluate the effect of salinity stress activity of superoxide dismutase, photosynthetic proteins involved and sodium and potassium contents on maize line seedlings, a factorial experiment based on completely randomized design with four replicates was performed under greenhouse conditions. Two maize inbred lines as B73 and MO17, and two salinity levels including 0 and 200 mM NaCl were considered as the first and second factors, respectively. The results indicated that salinity stress had a significant effect on the dry weight and Na+ and K+ contents in maize line seedlings. Electrophoresis analysis of superoxide dismutase enzyme revealed three different isoforms. Salinity stress increased the activity of superoxide dismutase isoforms. The results obtained from 2-D electrophoresis of maize lines showed 10 and 2 repeatable protein spots in photosynthetic system in B73 and MO17 maize lines, respectively. Salinity stress increased the expression of 12 protein spots involved in photosynthesis of maize lines. As results indicated that MO17 line more salt-sensitive than B73 line. The results show that maize lines as B73 and MO17 can control the adverse effects of salinity stress by increasing the activity of superoxide dismutase isoforms and enhancing the expression of proteins involved in photosynthesis and regulating the Na+ and K+.

In order to identification of effective traits on root yield and also determination of cause-and-effect relationships between in 20 different sugar beet cultivars, an experiment was carried out in West Azarbaijan Agricultural and Natural Resources Research and Education Center, Miandoab Research Station based on RCB design with four replications in 2017 crop season. The assayed traits included root yield, sugar yield, white sugar yield, sugar content, white sugar content, extraction coefficient of sugar, root α-amino nitrogen, sodium and potassium, alkalinity coefficient and molasses sugar. The results of analysis of variance showed that difference between studied cultivars for amino nitrogen (α-N) all traits was significant at the 0.05 probability level and for other traits was significant at the 0.01 probability level. Phenotypic and genotypic coefficients of variation for most traits were high, indicating relatively high variability in studied cultivars for evaluated traits. Correlation coefficients between traits showed that there is the most negative and significant correlation between root yield trait with sugar content (-0.62), white sugar content (-0.53), alkalinity coefficient (-0.52), potassium (-0.49), sodium (-0.45) and also molasses sugar content (-049) traits, and the most positive and significant correlation with sugar yield (0.95), white sugar yield (0.90) and extraction coefficient of sugar (0.58) traits, respectively. In multiple regression analysis by stepwise method, sugar content and white sugar content, amino nitrogen and alkalinity coefficient traits were entered into model, respectively, that explained 82 percent of root yield variations. Based on correlation, stepwise regression and path analysis results, among the studied traits, amino nitrogen (0.35) and white sugar content
(-0.31) traits with most direct effect were effective on root yield and will be useful in identifying genotypes.

In order to estimate genetical parameters, general and specific combining ability of bread wheat to determine proper parents for crossing and producing new cultivars, six promised lines planted in randomized complete block design with three replications, in 2017-18 cropping and varieties including, Falat, Mehergan, Ehsan, Sistan, Bam and N-80-19 were planted in Eraghi Mohalle (Gorgan) station in 2016-17 cropping season. A full diallel mating among six parents for generating F1 progenies were done. Sixparental genotypes and 30 F1 progenies were season. The results revealed that cultivar Ehsan was the best general combiner for hundred grain weight. Cultivar Ehsan and Line N-80-19 had the highest general combining ability for grain yield and biomass, respectively. Therefore, it is recommended that these genotypes can be applied in hybridization to increase grain yield and biomass. Additive variance of traits including plant height, peduncle length, grain weight in spike and hundred grain weight was more than dominance variance. Furthermore, Ehsan cultivar had the highest general combining ability (GCA) for grain yield and biomass and hybrids raised from 2×3 (Ehsan×Mehrgan) cross had the highest specific combining ability (SCA) for grain yield and biomass.

In order to determine the most suitable quantitative drought tolerance indices and drought tolerant moldavian balm (Dracocephalum moldavica L.) ecotypes, two experiments (under normal and drought stress conditions) were carried out using randomized complete block design with four replications. In this research, drought tolerance indices such as tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress tolerance index (STI), yield index (YI) and yield stability index (YSI) were calculated using shoot dry weight under non-stress (Yp) and drought stress (Ys) conditions. The results of combined analysis of variance revealed that ecotype, stress and stress × ecotype were significant (p<0.01) in shoot dry weight. Analysis of variance indicated that there were significant differences (p<0.01) between the ecotypes for Yp, Ys, and MP, GMP, HM, STI and YI indices. There were positive significant correlations between MP, GMP, HM, STI and YI with Yp and Ys and so MP, GMP, HM, STI and YI were recognized the most suitable indices for screening the ecotypes. Distribution of ecotypes in biplot graph represented the genetic diversity among ecotypes for selecting them based on drought tolerance and comparison of different moldavian balm ecotypes using multivariate biplot graph indicated that Faridan, Garmsar, Khomeinishahr and Urmia ecotypes are considered as superior ecotypes in both conditions because of locating of these ecotypes next to the vectors of suitable drought tolerance indices. Cluster analysis showed that Faridan, Garmsar, Khomeinishahr and Urmia ecotypes could be suggested as drought tolerant ecotypes.

To evaluate the adaptability and stability of root yield and white sugar yield in sugar beet genotypes, 47 sugar beet genotypes were evaluated in a randomized complete block design with six replications in four regions of Hamedan, Kermanshah, Shiraz, and Mashhad at 2019 crop year. In order to analyze the pattern of genotype by environment interaction, additive main effects and multiplicative interactions (AMMI) model and GGE biplot graphical method was used. The results of additive main effects (analysis of variance) and multiplicative interactions (principal component analysis) showed that the effect of genotype, environment, and genotype in environment interaction on root yield and white sugar yield were significant (p-value < 1%). The results showed that the first two components explained 89.10 and 95.48% of the variance of the interaction for root yield and white sugar yield, respectively. The biplot diagram of the first main interaction component and mean of root yield and white sugar yield for genotypes and environments showed that genotypes 28, 26, and 43 with higher than average total yields and lowest values for the first interaction component Known as stable genotypes, Based on the results of the two-dimensional diagram related to the first two main components of the interaction of genotype in the environment, Genotype No. 24 had the highest specific adaptability for Hamedan, Shiraz and Mashhad locations in term of root yield and white sugar yield. While genotype 46 in terms of root yield and genotype 36 in terms of white sugar yield showed good specific adaptability to the Kermanshah environment. Also, genotype No. 37 in terms of root yield and genotype 44 in terms of white sugar yield had higher general compatibility than other genotypes. Compared to foreign control cultivars, hybrids 28, 26, and 43 had suitable root yield, white sugar yield, and stability, and their selection is recommended for future breeding programs.