پژوهشنامه اصلاح گیاهان زراعی
پیاپی 39 (پاییز 1400)

In order to selection of soybean genotypes under different amounts of sulfur, 30 soybean genotypes were evaluated at three levels of sulfur (control, 5 and 10 g/Kg soils) concentration of sulfur was 98 % and it was added as 0, 0.1 and 0.2 % of evaluated soils. The experiment was lay out as a factorial arrengment in a randomized complete block design with three replications at Sari Agricultural Science and Natural Resources University in 2016. Evaluated traits included height of main branch, height of first sub branch, number of main branch pods, number of sub branch pods, 100 seed weight, total chlorophyll content, chlorophyll a content, chlorophyll b content, carotenoid content, sulfur content, Oil percentage, protein percentage and grain yield per plant. The results of analysis of variance of studied traits showed that sulfur application has a significant effect (P<0.01) on the studied traits. According to the results of means comparisons, the highest amounts of oil and protein percentage were obtained in Dayr and Williams genotypes at the third level of sulfur. The highest and lowest grain weights were observed in Hill and Vabash genotypes in the second level of sulfur, respectively. The results of the cluster analysis using Ward method, divided the soybean genotypes into two distinct groups. The genotypes were grouped using principal component analysis and biplot, too. According to the results of the cluster analysis, genotypes of the first group, which had high mean for the studied traits, were selected. Therefore, these genotypes can be used to select high-yielding genotypes and desirable agronomic traits that have the ability to absorb more sulfur in future breeding programs.

In order to identify susceptible and tolerant rice lines to drought stress in a recombinant rice population, a total of 40 F7 lines were obtained from a cross between a local cultivar, Gharib, and an improved cultivar, Sepidrood, were evaluated in two environments, control, and drought stress, in the year of 2017 at the Rice Research Institute of Iran. The results of the phenotypic evaluation of the studied lines showed that all genotypes, while having general hypersensitivity and decreasing growth under drought stress conditions, showed different responses to drought stress. The results of cluster analysis of morphological traits showed that L27, L38, L29, L40, and L39 lines were identified as the most tolerant genotypes with the lowest percentage of trait reduction, the highest grain yield, and earlier maturity. After them, the L9, L17, L21, L26, L30, L12, L19, L23, L25 lines, Sepidrood, Khazar and Hashemi showed the highest yield under drought stress conditions. The regression analysis showed that 13 of the 20 studied microsatellite markers including; RM11943, RM431, RM12091, RM416, RM236, RM16030, RM555, RM211, RM423, RM12146, RM520, RM12023, and RM233A, were associated with more than one morphological trait related to grain yield under drought stress Therefore, these markers can be used in different rice breeding programs to screen and select the drought-tolerant cultivars and lines in areas under this environmental stress.

This study was performed to investigate and determine the virulence /avirulence spectra of five genes of wheat yellow rust disease collected from Karaj (174E158A +), Zarghan (103E16A +, Yr27), Sari (6E150A +), Sarakhs (Y72727 + A, Moghan (247E235A +). International standard and differential genotypes were used to determine the races of wheat yellow rust disease. Then, the response of 297 different bread wheat genotypes to these races was evaluated in a completely randomized design with two replications under greenhouse conditions and at a temperature of 15 ° C. In the study of correlation between different breeds, it was found that Sari (6E150A +) and Karaj (174E158A +) have the highest correlation. Also, simple analysis of variance for three traits of infection type, pustule size and pustule density showed high genetic diversity between the studied genotypes. Combined analysis of variance showed a significant effect of genotype, race and genotype-race interaction for infection type trait. The effect of genotype and race were also significant for pustule size and pustule density. The results of correlation analysis of traits in different races showed a significant and positive correlation between them. Cluster analysis divided the genotypes into three groups: resistant, semi-resistant (semi-susceptible) and susceptible, which confirmed the results of resistance reactions of wheat genotypes to different varieties of yellow rust. Based on cluster analysis, genotypes 6, 36, 39 and 44 had the lowest infection type (higher resistance) than all five races of yellow rust. The results of cluster analysis also showed the presence of commercial cultivars PARSI, KARAJ2, CHAMRAN2, PANJAMO62, MAHDAVI, PISHGAM, INIA66 and RIJAW in the group of resistant wheat, which can be obtained by using tree analysis to give the parent resistance to this disease.

Salinity stress is one of the unfavorable environmental conditions leading to loss of yield in wheat. Therefore, the discovery of differentially activated transcripts and understanding of their role in the salinity-treated wheat are indispensable for improving salt resistance. To explore the salinity-responsive genes, we assayed transcripts from salt-stressed and control wheat by using cDNA-AFLP approach. Based our observations, 31 transcript-derived fragments (TDFs) were successfully sequenced. BLASTX search revealed that most of the TDFs were belonged to the genes responsible for metabolism and energy, cell defense, transcription control, transport, signal transduction, and protein degradation functional groups. Real-time polymerase chain reaction displayed that 18 TDFs up-regulated and four down-regulated under salinity. Overall, these findings can enhance our understanding on the molecular mechanisms of salt response in wheat. Besides, the identification of novel salinity-responsive genes can represent important information, which in turn, assists the improvement of wheat tolerance to this stress in the field.

In order to evaluate durum wheat lines in terms of frost stress tolerance, 45 promising durum wheat lines resulting from crosses between different parents were assessed using stress tolerance indices. This experiment consisting of greenhouse and laboratory tests was performed in the Faculty of Plant Breeding of MohagheghArdabili University in the 2017-18 crop year. In this experiment, wheat lines at seedling stage were studied. Durum wheat lines were planted in a factorial design based on randomized complete blocks with three replications. Plants up to 3 to 5 leaf stage were kept in greenhouse conditions. The pots were then taken to a cold room at 4°C to prepare for stress. Based on biological performance, tolerance indices (TOL), stress sensitivity (SI), average production (MP), stress tolerance index (STI) Geometric mean of production (GMP), Harmonic mean of production index (HARM), Yield reduction index (Yr) and Root and shoot tolerance index (TI) were calculated. The results of analysis of variance showed that the studied lines had significant differences in terms of MP, GMP and HARM traits and Yr and Ti indices were significant in stress. The interaction of the line in stress was insignificant for all indices. Due to the correlation between performance and indices, the most appropriate indices were MP, GMP, HARM and TOL. Comparison of mean lines and stresses were examined separately. The maximum correlation coefficient was related to the relationship (0.999) between STI index with SI, Yr with SI and Yr with STI. In general, GMP, MP and HARM indices are the most appropriate indices to evaluate the stress tolerance of lines at all levels. The study and TOL index were suitable for higher stress levels. Study of lines by indices using cluster analysis, detection function analysis and factor analysis showed similar results. The results of cluster analysis and factor analysis with the first three factors introduce lines 25, 26, 27, 28, 31, 36 and 39 as the most tolerant lines and lines 11, 13, 15, 17, 18 and 19 as the most sensitive. They were identified. In factor analysis, the first three factors explained 97.52% of the available variance and the indices of STI, SI, Yr, Ti aerial parts, MP, GMP and HARM They had the highest value and were the most effective indicators in the distribution of lines. According to the three-dimensional diagram of line distribution, the highest factor coefficients based on the first three factors were related to lines 5, 7, 25, 26, 27, 28, 31, 36 and 39.

The use of physiological traits is one of the best methods for the rapid production of new varieties, therefore, in order to evaluate photosynthetic factors and their relationship with total yield in red beans, an experiment was conducted in a randomized complete block design with three replications at Khairabad Research Station in Zanjan under normal irrigation conditions during two consecutive crop years (2018-2020). The studied genotypes showed significant differences in all traits (except photosynthetically active radiation). The studied genotypes showed significant differences in all traits (except photosynthetically active radiation). These results indicate that there is a high genetic diversity between genotypes in terms of photosynthesis-related traits and, consequently, yield capacity. Genotypes G1, G2, G4, G9 and G12 showed higher photosynthesis, stomatal conductance, water use efficiency and mesophilic conductivity than other genotypes. G6, G7 and G3 genotypes had less mesophilic conductivity, water use efficiency and photosynthesis than other genotypes. There is a significant negative correlation between photosynthesis and sub stomatal CO2 and a significant positive correlation with the stomatal conductance, mesophilic conductance, water use efficiency and yield; therefore, genotypes with more photosynthesis, in addition to high stomatal conductance, have higher mesophilic conductivity and, in other words, are more efficient in using carbon dioxide entering the stomatal. As a result, the concentration of sub stomatal CO2 is reduced, so there is a close relationship between photosynthesis, water use efficiency and mesophilic conductivity. Regression analysis showed that when total yield is considered as a function variable, the photosynthetic active radiation and photosynthesis justify grain yield. However, when the photosynthesis is a function variable, the traits of photosynthetic active radiation, sub stomatal CO2, leaf temperature, and transpiration rate justify changes in photosynthesis. Due to the diversity of photosynthetic indices in genotypes, this experiment can be performed in different stress conditions such as drought and salinity and the results can be used with normal conditions to select efficient genotypes in stress conditions.

In this study, the fruit heritability of 15 different accessions of Iranian tomato (Urmia, Gorgan, Kafshgiri, Sari, Rasht, Kurdistan, Kermanshah, Semnan, Shahroud, Zanjan, Varamin, Esfarayen, Neishabour, Sirjan, Hamedan) and fruit set through pollen grain source, were measured in in Kalaleh city of Golestan province in 2019. The experiment was conducted in a randomized complete block design with 15 populations in three replications (five plants per population). After pollination, the fruits were evaluated in the laboratory and their seeds were extracted and collected. Traits including number of fruits per plant, fruit weight, number of cells and number of seeds were evaluated. Phenotypic diversity, genotypic diversity, environmental diversity and general heritability of traits were calculated. The results showed that fruit weight, fruit length and number of locular cavity respectively with 200 g, 8.83 mm and 12 had the highest value in Varamin accession. In Kermanshah accession, the highest number of fruit seeds was recorded with 323 pieces per fruit. Kafshgiri accession, with a length of 3.33 mm and a fruit weight of 9.17 g, is one of the smallest fruits. Fruit weight, fruit length, number of locular cavity and number of seeds had high heritability from 88 to 92%. In all studied traits, the coefficient of genetic diversity was higher than the coefficient of phenotypic diversity, which showed less impact of environmental factors on these traits. The results also showed that the fruits obtained from the cross-pollination of different accessions (offspring from cross-pollination) had the lowest amount of fruit weight and number of seeds and the offspring from self-pollination had a higher amount. However, non-self pollen grains had no effect on fruit length and locular cavity. From the results of the present study, it can be inferred that the type of pollen grain can affect the quantitative characteristics of tomato seeds and fruits so that most traits in the cross-pollination had significantly lower values ​​than the self-pollination. In order to increase the production efficiency of tomato, pollination with self pollen grains should be considered.

Sesame is an oilseed crop with high resistance to dehydration. This plant with the minimum moisture requirements has a good performance compared to the other crops in the summer. Recognition of high-yielding genotypes under these conditions is one of the priorities of sesame breeding programs. In the current study, 10 promising sesame lines derived from segregating generations that were superiors in the preliminary evaluations were evaluated along with 6 local genotypes in the form of RCBD with 3 replications in the Sistan region during two cropping seasons. Different quantitative and phenological traits were evaluated during the growing periods. ANOVA results indicated significant differences among genotypes for their grain yield, biological yield, plant height and thousand seed weight. Using Duncan's mean comparison method, genotypes 3, 13, 5 and 7 were identified as superior genotypes. The correlation study of the studied traits showed a positive and significant relationship between grain yield and 1000-seed weight. Also, biplot diagram of genotypes distribution on the first two components showed that genotypes 3, 5 and 13 are different from other genotypes in the term of quantitative traits and were considered as the best ones. Cluster analysis for all traits using Ward method also distinguished genotypes 3 and 13 from other genotypes. Additionally, genotypes ranking based on the selection index of ideal genotype (SSIG) revealed genotypes 3 and 13 as high ranking genotypes. Therefore, using different multivariate analysis methods, genotypes 3, 13 and 5 are introduced as desirable yielded genotypes with high compatibility in the Sistan region.

To evaluate 38 maize hybrids, an experiment based on randomized complete block design with three replications at the Moghan Agriculture Research Station during the 2020 growing season. The results indicated that a significant difference had among maize hybrids for ear yield, plant height, ear height, leaf temperature, chlorophyll index, maximum fluorescence (Fm), variable fluorescence (Fv) and maximum quantum yield of PSII (Fv/Fm). K74/2-2-1-4-1-1-1 × K3640/3 hybrid (No. 9) with high ear yield and photosynthetic system introduced the best hybrid to comparing with other hybrids. The range of heritability was from 3% for minimum fluorescence (Fo) to 71 % for ear height. Path analysis revealed that minimum fluorescence (Fo) and leaf temperature had the highest and positive direct effects on ear yield. The cluster analysis, with ear yield, plant height, ear height, leaf temperature, chlorophyll index, and quantum yield, was classified 38 maize hybrids in three different groups, and the third group with 9 (K74/2-2-1-4-1-1-1 × K3640/3) was the most desirable.

Salinity stress is one of the most important abiotic stresses that restricts the growth of crops. In order to group the rice genotypes resulting from crossing of improved cultivars at salinity stress conditions, a factorial experiment was conducted in a randomized complete block design with three replications under greenhouse conditions at Sari agricultural sciences and Natural Resources University in 2018. The treatments in the experiment included salinity stress factor at three levels (control, 4 and 8 dS/m) and nine rice genotypes. The different genotypes were grouped based on stress tolerance indices. The results showed that salinity stress reduced grain yield in all genotypes. The highest reduction in grain yield was related to salinity of 8 dS/m in all genotypes. Cluster analysis showed that a good variation between the studied genotypes in terms of stress tolerance indices at the salinity of 4 and 8 dS/m. Based on the results of tolerance indices the Jelodar × Danesh genotype had the highest value in terms of tolerance indices in both salinity conditions of 4 and 8 dS/m and was recognized as a tolerant genotype. Also, the genotype Danesh × Parto, in salinity of 4 dS/m and Danesh genotype in salinity of 8 dS/m, were known as susceptible genotype.

Path analysis is one of the oldest methods of knowing the direct and indirect effects of traits on yield, but the widespread application of this approach is limited by the problem of multi-collinearity, that has been addressed in the present study. A total of 298 bread wheat genotypes were evaluated during the two cropping years in the lattice design and the path analysis of grain yield was studied by simple and ridge methods. The highest direct effect on grain yield in the first year were related to spike weight, number of seeds and 1000-seed weight, respectively, and in the second year were related to number of seeds, 1000-seed weight and spike weight, respectively. Spike weight and number of seeds in the first year had an indirect effect on yield through each other as well as through spike length and plant height. In the second year, the number of seeds and 1000-seed weight through the weight of spikes showed the most indirect effect. Day to booting and day to flowering traits in both years and spike weight in the second year had a high multi-collinearity that the use of constant k =0.10 in ridge causal analysis overcame this problem. Finally, in contrast to simple path analysis, ridge path analysis showed that the spike weight through the number of seeds had an indirect effect on grain yield in the second year. According to the results, it is recommended to consider the issue of multi-collinearity between traits in future path analysis studies.

In order to investigate grain yield and some of the agro- morphological traits genetical characterization in bread wheat, seven cultivars of wheat including Hamun, Alamut, C-84-12, Gaspard, Ghods, Moghan 1 and Afshar were evaluated in a one-way diallel cross experiment. Parents and hybrids resulting from their one-way dial cross (21 hybrids) during the 2018-2019 crop year were studied in a randomized complete block design with three replications. Analysis of variance related to genotype effect was significant for grain yield, 1000-kenal weight, plant height, peduncle length, spike length, awn length and stem diameter. The general combining ability of Gaspard cultivar was positive and significant for grain yield. Regarding grain yield, the specific combining ability of Hamun × C-84-12, Alamut × Moghan 1, Alamut × Afshar, C-84-12 × Moghan 1 and Gaspard × Ghods were positive and significant and the specific combining ability of Hamun × Afshar and Gaspard × C-84-12 hybrids were negative and significant. GGE biplot showed two heterotic groups, the first group including Hamun, Moghan 1 and Afshar cultivars and the second group including Alamut, C-84-12, Gaspard and Ghods cultivars. Due to the additive effects in the studied plant materials and the cumulative effect on the inheritance of genes to the next generation, it is possible that through selection in the first generations to be useful to increase yield.

In order to study some agronomic characteristics and identify the desirable genotypes using different statistical methods, 15 lentil genotypes received from ICARDA were evaluated in a randomized complete block design with three replicates under rainfed conditions at Sarab-Changai Research Station, Lorestan Agricultural and Natural Resources Research and Education Centre, Khorramabad, Iran during 2019-2020 cropping year. According to the results, analysis of variance indicated significant genotypic diversity between the studied genotypes in terms of most traits. The correlation between grain yield per plant and most of the traits, especially yield components, was positive and significant. Genotypes 13, 14, 7 and 1 were known as the best and genotypes 15, 12 and 4 were identified as the weakest genotypes based on the results of various statistical methods including mean comparisons, cluster analysis, “genotype × trait” biplot and SIIG index. The highest direct positive effect on “seed yield per plant” belonged to the “number of one-seeded pods per plant” (0.580) and “hundred seed weight” (0.437), respectively, and therefore these traits can be applied as selection criteria. Moreover, genotype 7 was the best genotype in terms of important agronomic traits and has the potential to be used in the future breeding and subsequent agronomic research programs.

Numerous environmental factors affect the growth and development of crop plants. Salinity affects crop production through mineral imbalance (toxicity or deficiency of elements), osmotic and oxidative stresses. In this study, using real-time PCR technology, changes expression levels of SOS2, MYB-related and HD-ZIP genes were evaluated under different salinity stress conditions (2, 5, 8, 11 and 14 dS/m) in two different oil seed sunflower lines (AS5305 and 9CSA3). Leaf sampling was performed at 8-leaf stage at four times; 6, 12, 24 and 48 hours after salinity stress application. SOS2 involve in signal transduction and MYB-related and HD-ZIP act as transcription factors under abiotic stresses. According to the results, the expression pattern of all three genes is different in the studied lines in response to salinity stress. Comparison of the two lines shows that the major increase in expression occurred in line AS5305, and where an increase in expression in line 9CSA3 is seen, in comparison, the rate of increase in corresponding times and salinity is higher in line AS5305 (tolerant line) than that in line 9CSA3 (sensitive line). The results indicate the positive role of these genes in the mechanism of sunflower resistance to salinity stress. On the other hand, in this study, by confirming the resistance of AS5305 line to salinity stress at the molecular level, it is possible to potentially use this line in the production of salinity-resistant hybrid cultivars in plant breeding programs.

Oilseed rape is one of the most important oilseeds in Iran. Due to limited genetic resources, the development of its cultivated area requires genetic diversity by hybridization in breeding programs and, finally, introducing potential lines to the agricultural community. Therefore, this study aimed to generate genetic diversity by hybridizing eight spring rapeseed genotypes using a complete diallel design and investigating the inheritance and genes action of some agronomic traits, yield, and its components in F1 progeny in a complete block design with three replications in 2018- 2019 and 2019-2020 crop years. Analysis of variance components showed that the mean squares of general combining ability were significant only for branching height, podding height, pods per lateral branches, and pods per plant. In contrast, mean squares of specific and reciprocal combining ability were significant for all traits. The highest and lowest values of sprecific heritability obtained for podding height (18%) and grain per pods (0.4%), respectively. The GCA/SCA ratio also indicated the importance of additive effects for branching height, podding height, pods per lateral branches and pods per plant. Parents SPN-182 and SPN-202 had a positive and significant general combining ability for lateral branches, pods per lateral branches, pods per plant, grain per pod and grain yield. SPN-207×SPN-182 and SPN-206×SPN-182 hybrids with the highest positive and significant specific combining ability are essential for grain yield traits to produce single cross hybrids.

Genetic diversity is the base for survival of plants in nature and for crop improvement. Diversity in plant genetic resources provides opportunity for plant breeders to identify new and improved cultivars with desirable characteristics. In order to study the variation of barley inberd lines using the selection index of ideal genotype (SIIG), 108 pure lines in the non-repeating Augment design with four controls in three blocks were evaluated in the farm of Darab Agricultural and Natural Resources Research Station in cropping year of 2017-18. The results of ANOVA showed a significant difference among studied lines for all traits (except for the days to flowering) which indicated the existence of variation among the lines. The results of REML analysis showed that, the lowest heritability of traits was related to 1000-kernel weight (0.001) and the highest heritability was related to days to maturity and days to flowering (0.79 and 0.77), respectively. The results of the SIIG index indicated that line 18 with the highest SIIG (0.767) was the best and line 75 with the lowest SIIG (0.149) was the weakest line in this study. In order to evaluate the efficiency of SIIG index in selecting the best lines for grain yield, 1000 kernal weight and plant height, the lines were grouped according to SIIG index in 6 categories. The results showed that as the amount of SIIG index decreased, grain yield, 1000 kernal weight and plant height were also decreased, but there was no significant change in the days to flowering and days to maturity. Also, the results of grouping of lines based on SIIG showed that the average grain yield of groups 1, 2 and 3 was higher than the average yield of the three controls: Nimroz, Auxin and WB-94-4. Also, there was relative conformity between the SIIG index and cluster analysis in this study. This research showed that the SIIG index was able to categorize the genotypes according to the three traits of grain yield, 1000 kernal weight and plant height, simultaneously.

Stachys lavandulifolia is one of the medicinal plants that is widely distributed in Iran and has many medicinal properties. Few studies have been conducted to study the diversity between different populations of mountain tea. For this purpose, a study was conducted on 26 populations of Stachys lavandulifolia in the region of northwestern of five provinces (East Azerbaijan, West Azerbaijan, Ardabil, Zanjan and Hamedan) based on a completely randomized design with three replications in 2019. The results of analysis of variance showed that the differences between different populations based on plant height, fresh and dry weight of the plant, length and diameter of flowers and fresh weight of flowers were significant at the level of one percent. The highest fresh weight of flowers was observed in P3 population at 1.32 g. In contrast, the lowest fresh weight of flowers belonged to P1 population (0.32 g). Based on the results of analysis of variance, it was observed that flower dry weight, leaf length and width and number of leaves at the level of one percent and fresh and dry weight of leaf at the level of five percent were significant. The results of mean comparison showed that the highest and lowest rates of flower dry weight were related to P3 and P1 populations of 0.64 and 0.13 g, respectively. The dendrogram obtained from cluster analysis showed that 26 populations of Stachys lavandulifolia were divided into five separate groups. The comparison of the mean between the groups obtained from cluster analysis showed that the highest amount of fresh flower weight belonged to the third group at 0.96 g. The results of principal component analysis showed that four components had an eigenvalue higher than one and in total accounted for 84.29% of the total variance. Principal Component analysis the morphological traits in most cases confirmed the results of cluster analysis. In the first component, plant height, fresh and dry weight of the plant, fresh and dry weight of flowers, leaf width, number of leaves and fresh and dry weight of leaves, and the second component related to flower length, third component, number of leaves and fourth component, diameter of flowers had the highest factor loadin.. Based on the results of correlation analysis, it was observed that there was a positive and significant correlation between leaf dry weight with plant dry weight (0.49), flower dry weight (0.47), leaf length (0.51) and leaf fresh weight (0.65). In general, the results showed that there is a very high diversity between populations and this diversity can be due to habitat conditions or genetics of the populations.

The genotype × environment interaction is a major challenge in the study of quantitative traits because it reduces yield stability in different environments and also it complicates the interpretation of genetic experiments and is difficult to makes predictions. In this regard, to analysis of genotype × environment interaction and determine the yield stability of sunflower genotypes, 11 new sunflower hybrids along with 4 cultivars were evaluated in a randomized complete block design with four replications in four experimental field stations (Karaj, Sari, Kermanshah and Dezful) during two cropping seasons. In order to analysis of genotype × environment interaction was used the multivariate method of additive main effects and multiplicative interaction (AMMI). The results of combined analysis of variance indicated that 57.68, 7.60 and 16.93 percent of total variation were related to the environment, genotype and genotype × environment interaction effects, respectively. Also, the results showed that the first five principal components of AMMI were significant and described 97.64% of the variance of genotype × environment interaction. Based on biplot graph of mean seed yield and the first interaction principle, the genotypes G3 and G5 were identified as a high yield and stable genotypes. Also, the Dezful and Kermanshah environments due to their high interaction were recognized as the most ideal environments for distinguishing and separating sunflower genotypes. The cluster analysis of the studied environments was divided into two groups. According to the results of cluster analysis, Karaj, Sari, Kermanshah and Dezful locations were located in a group that indicates these locations had the high predictability and repeatability power.

Water deficit is one of the main problems in reducing agricultural production. Due to arid and semi-arid climatic conditions, identifying genotypes tolerant to water deficit stress is of great importance in Iran. In this regard, this study was conducted at the University of Tabriz in 2019 by investigating the effect of water deficit stress on ten sugar beet genotypes in split plots based on randomized complete blocks design in three replications. The main factor consisted of two irrigation levels (optimal and water deficit), and the sub-factor included ten sugar beet genotypes. In this experiment, we planted sugar beet seeds in PVC tubes. The evaluated traits included malondialdehyde, hydrogen peroxide, proline content, chlorophyll a and b, carotenoids, and soluble sugars. Based on the analysis of variance, the effect of irrigation, genotype, and irrigation interaction × genotype for all traits was significant at the probability level of one percent. Water deficit stress reduced chlorophyll a, b, and carotenoid traits. Water deficit stress also increases the properties of malondialdehyde, hydrogen peroxide, proline content, and soluble sugars. The genotype of number five was identified as a tolerant genotype based on malondialdehyde, hydrogen peroxide, and proline content indices. Based on chlorophyll a, b, carotenoid, and soluble sugars indices, The genotype of number ten was identified as a genotype tolerant to water deficit stress. Due to the tolerance of genotype No. 10 to salinity stress, chlorophyll indices and soluble sugars can be used to select genotypes tolerant to water deficit stress.

Terminal heat stress has been recognized as the most widespread and detrimental type of heat stress in the world. In southern regions of Iran like Khuzestan, delay in planting date causes pollination and grain filling stages to be exposed to high temperatures, resulting in yield reduction. Developing heat tolerant cultivars is one of the ways to deal with heat stress. In this study, to identify resources of heat tolerance in wheat germplasm, a total of 203 bread wheat accessions with three control cultivars were planted in normal and delayed planting dates as an augmented experimental design in Ahwaz and the agronomic traits were evaluated. The results showed that almost all the evaluated traits were reduced in heat stress conditions compared to normal conditions. In both normal and heat stress conditions, some superior accessions were identified in terms of the studied traits compared to the control cultivars. In the biplot based on the principal components under heat stress conditions, 64 accessions along with control cultivars were located in the area of superior characteristics in terms of grain weight of five spikes, number of florets per spike, number of grains per spike, number of spikelets per spike, spike length and plant height. The studied accessions were divided into five groups by cluster analysis. The results showed a high diversity in the studied genetic material and the accessions superior to the control cultivars in terms of the studied traits were identified which can be used in future breeding programs.