فهرست مطالب ساسان گلچشمه

The study of genetic diversity with the help of molecular markers is the main precondition and an important step in the improvement of vegetable plants, including tomato and is the basis for the effective use of heterosis and the protection of genetic pools. Several studies have been conducted using molecular markers between different tomato lines, but there is little studies in Iran. Based on this, the present study intends to estimate the genetic distance between a numbers of tomato lines using ISSR molecular markers.

In the present study, 12 tomato lines were investigated using microsatellite primers (ISSR) at Sari University of Agricultural Sciences and Natural Resources. Polymerase chain reaction (PCR) was performed by ISSR primers and PCR products fractioned on 1.5% using agarose gel electrophoresis then the bands were analysed.

The primers used showed acceptable polymorphism (85.28) and suitable score able banding patterns. The highest and lowest polymorphism information content (PIC) with values of 0.40 and 0.22 were related to ISSR2 and ISSR10 primers, respectively. The ISSR2 primer was more efficient than other primers in identifying and classifying the studied lines. The degree of genetic similarity varied from 0.23 to 0.95 between the studied lines and lines Fanal and Harlekyn had the most similarity and lines CP with Bibor and after that SP with Bibor showed greatest genetic distances. Results of cluster analysis and evaluation of quantitative characterestics of studied lines showed that genotypes 4, 5, 6 and 8 placed in first group had better yield and earliness comparing other genotypes.   

Lines CP, SP and Bibor had a great genetic distance from each other and hybridization between CP and SP with Bibor as well as utilizing of selected genotypes in first group is recommended for next breeding programs in tomato. The ISSR2 primer has useful information in distinguishing the studied lines than other primers and its useful in breeding programs of tomato.

Tomato is a self-pollinated crop and has a high potential for heterosis production. Tomato has a wide range of diversity in terms of vegetative and fruit traits. Therefore, learning information about the genetics of the tomato plant and the inheritance of its various traits to the next generation will help plant breeders to use appropriate breeding methods to improve them. One of the methods that is used to know the genetic structure of plants, identify parental lines and determine their combining ability is line × tester analysis. Line × tester analysis provides information about general and specific combining of parents and can be useful in estimating different types of gene effects such as additive and non-additive effects. In most of the developed countries, many researches have been done in relation to hybrid production and combining ability among tomato lines, and sometimes the inferred results are different from each other. In Iran, few studies have been done about crossing cultivars and their hybrids, and most of the seeds used by farmers are imported from other countries. Therefore, this study intends to evaluate genetic variance components, general and specific combining ability of some quantitative traits in a number of tomato lines and testers and their hybrids by using line × tester analysis.
 
This research was conducted in Sari Agricultural Sciences and Natural Resources University, Mazandaran Province, Iran in 2022. Two modified cultivars SC and V as lines and three modified cultivars L, R and MZ as testers were crossed with each other to create F1 hybrids. Six F1 genotypes and their parents (11 treatments in total) were cultivated in the farm in a randomized complete block design with three replications. The evaluated traits included the number of days to the first flowering, earliness, number of fruits per plant, fruit weight per plant (g), fruit yield (g), fruit length and width (cm). In order to analyze the variance of the experimental design to search for diversity between treatments, to separate the effects of treatments into their components based on line × tester analysis, to mean comparison with Duncan's test, and also to calculate the general and specific combining ability, R statistical software was used. Also, in order to calculate additive and non-additive variances, Singh and Chaudhary's method was used.
 
The results of line × tester variance analysis showed that the mean squares of parents and testers were significant for all traits except fruit length and width, and the mean squares of crosses and lines were significant for all traits except fruit length. The effect of line × tester was significant for all traits except the number of fruits per plant and fruit length. The line of SC to improve the number of days to first flowering, earliness, plant height, fruit weight per plant, and fruit width, and the line of V to improve the number of fruit per plant were the best general combiners with testers. The tester of L for improve all traits except yield, and the tester of MZ for improve plant height were the best general combiners with the maternal lines. Among the crosses, the SC×L cross for improve earliness and fruit width, and the SC×R and V×MZ crosses for improve plant height and fruit weight per plant, respectively, were favorable specific combiners. The mean comparison of the genotypes for some important traits showed that among the parental cultivars, the line of SC and among the crosses, the SC×L genotype had the lowest means for the number of days to first flowering and earliness. Also, the line of SC for the number of fruits per plant and the SC×L genotype for fruit weight per plant, yield and fruit width had the highest means. Also, the estimation of additive and non-additive variances indicated that in plant height and fruit weight per plant traits, additive variance plays the main role. While for the traits of the number of days to first flowering, earliness and yield, the contribution of non-additive variance was more than the additive variance.
 
According to the results obtained from this study, in future projects it is recommended to use parents that have significant general combining ability (GCA) for traits. Because such parents easily transfer the trait to their next generation. In this way, the line of SC was a good general combiner for the number of days to first flowering, earliness, plant height, fruit weight per plant and fruit width, and the line of V was a good general combiner for the number of fruits per plant. Among the testers, the tester of L was a good general combiner for improve the number of days to first flowering, earliness, number of fruits per plant, fruit weight per plant, and fruit width, and the tester of MZ recorded a high GCA for the plant height. Also, for the improvement of earliness and fruit width, the SC×L cross and for plant height and fruit weight per plant, SC×R and V×MZ crosses were favorable specific combiner. Mean comparison of genotypes showed that the SC×L cross is superior to its parents for the number of days to first flowering, earliness, fruit weight per plant, fruit yield, and fruit length and width. The traits of plant height and fruit weight per plant are more affected by additive variance, so the best breeding method to improve plant height and fruit weight per plant is selection from among the segregating population. The traits of number of days to first flowering, earliness and yield were affected by non-additive variance, so hybrid production is recommended to improve the mentioned traits.

Drought stress and consequent lack of available water for plants is one of the main causes of accumulation of reactive oxygen species (ROS) in various organs of plants, which is effective in reducing the yield of cereals such as wheat. The antioxidant system, which contains various enzymes and genes, is responsible for removing and detoxifying plants from ROS. Unfortunately, genes responding to drought stress and their enzymatic activities associated with spike and flag leaf of wheat have received less attention. Therefore, in the present study, photosynthetic parameters, key enzymes of the antioxidant system, and expression analysis of some genes involved in this system under field capacity (FC) and drought stress (DS) conditions in spike and flag leaves of wheat were investigated.

The present study was performed in Azadshahr Research Center, Golestan Province, Iran in 2021. The wheat cultivar used in this study was Qaboos. This cultivar was cultivated under two experimental conditions of field capacity and drought stress in a randomized complete block design with three replications in the field. In the present study, differences in net photosynthesis (PN) rate, transpiration (E), stomatal conductance (gs), chlorophyll (Chl), relative water content (RWC), and the activity of APX, DHAR, MDHAR, and GR enzymes involved in the antioxidant system of flag leaf and spike of wheat were examined under field capacity and drought stress conditions. Transcription levels of APX, DHAR, MDHAR, and GR genes were measured using qRT-PCR under drought stress and field capacity conditions. Flag leaf and spike of Wheat for photosynthetic parameters and enzymatic activities at 0, 5, 10, 15, 20, and 25 and relative gene expression at 0, 1, 3, 5, 10, 15, 20, and 25 days after anthesis (DAA) were harvested. The recorded data were analyzed by analysis of variance and all analyzes were performed by SPSS software. Mean differences were compared using Duncan's multiple range test at 5% probability level.

general, the spike had a better capacity to maintain net photosynthesis, transpiration, stomatal conductance, chlorophyll, and relative water content under drought stress conditions. This superiority reached its peak on the fifth day after anthesis. The enzymatic activity of the antioxidant system was normal under field capacity conditions. However, with the application of drought stress, APX, DHAR, MDHAR, and GR enzymes were affected in both spike and flag leaf of wheat and their activity increased, which indicates more activity of the antioxidant system in spikes and flag leaf of wheat for controls the level of ROS. After more days of grain filling, the activity of enzymes increased, and finally, after the plant entered the senescence stage, the activity of enzymes decreased to some extent. With drought stress, the antioxidant system in spike, especially from the 10th day after anthesis onwards, had a better performance. However, enzymatic activity in flag leaves under drought stress was not significantly different from field capacity conditions. Transcriptional levels of APX, DHAR, MDHAR, and GR genes associated with the antioxidant system increased under drought stress compared to field capacity conditions. It seems that the increase in enzymatic activity simultaneously with the increase in the level of transcription of the genes of the antioxidant system in the spikes and flag leaves of wheat is to counteract the oxidative damage.

the present study, spikes of wheat played a more important role in responding to water deficiency through the antioxidant system than its flag leaf. The results of this study showed a high potential of the spike compared to flag leaf in the face of drought stress and this results in future breeding programs in wheat can play a key role in selecting drought-resistant cultivars with high yield.

 Tomato is a product with a wide range of genotypes with different yields and selection based on this trait and its components can accelerate the breeding programs of this plant. The most important goals of tomato breeders have been to increase yield, disease resistance, early maturity, and improve the quality characteristics of the fruit. Therefore, awareness of genetic diversity in the population is an important step in plant breeding, and to achieve this goal, the studied genotypes must first be identified in terms of genetic potential and favorable agronomic traits. The usual approach for describing and evaluating populations requires cultivating sample populations and evaluating their morphological and agronomic characteristics. In this regard, multivariate statistical methods play an important role in studying genetic diversity and selecting appropriate parents. Unfortunately, the tomato cultivars used in Iran are often not at the favorable level in terms of important traits such as the number of days to fruit ripening, fruit weight, fruit yield, fruit length, and width, and few studies have been done on these traits. Therefore, this study was conducted to investigate the morphological diversity, evaluate the yield and its components among some imported tomato lines using analysis of variance, cluster analysis, and principal component analysis.

 This study was performed in Sari University of Agricultural Sciences and Natural Resources, Mazandaran, Iran in 2020. The plant material included 24 tomato lines imported from the Canadian Plant Gene Bank and one check variety. The experimental design used for morphological analysis was a randomized complete block design with three replications. Evaluated characteristics were included of the number of days to first flowering, number of days from germination to first fruit coloring (early ripening), plant height (cm), number of fruits per plant, average fruit weight per plant (g), plant yield (g), length and width of the fruit (cm). After measuring the characteristics at the farm and recording the data, analysis of variance was performed to examine the diversity between lines in terms of the studied variables, and Duncan test was used to compare the means and SAS software was used to test the correlation coefficients of the variables. Cluster analysis for grouping of tomato lines was performed based on the mean of the main data of standardized traits, which was determined by Euclidean distance to determine the distance between the lines, and the UPGMA method was used to merge the clusters. Principal component analysis was performed based on the mean of the main data of morphological traits.

 The results of the analysis of variance showed that there was a significant difference between all lines in terms of the studied characters. Also, principal component analysis based on morphological traits showed that the first two main components accounted for 75% of the total phenotypic variation in the data and the number of days from germination to first fruit coloring (-0.606), the number of days to first flowering (-0.516), fruit weight per plant (0.492), fruit width (0.480), fruit length (0.472), plant height (-0.445), fruit yield per plant (0.395) and the number of fruits per plant (-0.367) had the highest contribution in yield changes. Therefore, these variables might be taken into consideration for effective selection of parents for hybridization programs for broadening the genetic base in the population as well as to develop elite lines or F1 hybrids. UPGMA cluster analysis also divided the studied lines into nine groups. Group IX lines were in good condition in terms of yield traits and components, group VIII lines in terms of maturity and flowering, and group IV lines in terms of fruit number per plant. And the lines in groups I and V were in moderate condition for all traits. According to these results, the cross of the lines in the more distant groups can produce hybrids with high diversity and maximum heterosis.

 According to the main purpose of this study, which was to evaluate the yield and its components and according to the analysis performed, lines 8, 11, and 17 due to showing the least number of days to flowering and early, lines 10 and 14 due to having the highest yield, the highest fruit weight, and highest fruit length and width and lines 2, 9, 15, 21, and 24 due to having the highest number of fruits per plant and the favorable height are also recommended for use in tomato breeding programs.

The present study was performed to classify and study genetic diversity between Calotropis procera accessions from different regions of Kerman province (Iran) using ISSR markers. In total, DNA from 14 plant samples with nine ISSR primers was amplified by PCR and their banding pattern was obtained. The primers showed acceptable polymorphism (35.93) and minimum and maximum polymorphic information content (PIC) of primers in this study were 0.11 for ISSR9 primer and 0.41 for ISSR3 and ISSR8 primers, respectively. Genetic similarity based on Nei index was varied from 0.405 to 0.745 and the lowest genetic similarity was found between J3 (Related to Jiroft) and D2 (Related to Dosari) and the highest genetic similarity was found between J1 and J2 (both of them for Jiroft). By using UPGMA cluster analysis, samples divided into four groups, and the second and third groups contained more accessions. In terms of genetic similarity, two accessions of Jiroft 1 (J1) and Jiroft 2 (J2) which classified in the same cluster were closer. Also, the accessions collected from Anbarabad were at a longer genetic distance than other accessions. Principal coordinate analysis also showed that the first and second components justify 67 percent of obtained genetic diversity. In general, ISSR markers were useful for classifying Calotropis procera accessions and according to the obtained information about existence of genetic diversity between Calotropis procera accessions of Kerman province, this diversity could be useful in the future for breeding and production of Calotropis procera.

The present research was performed for studying morphological variation and investigating the presence of relationship between molecular markers related tillering in some genotypes of bread wheat under the field farm and laboratory conditions. In the field experiment, three seed densities including 150, 300 and 450 seed per square meter as the main plot factor and also 10 genotypes including the cultivars of Arta, Inia, Tajan, Darya, Shirudi, Golestan, Gonbad, Morvarid, Moghan3 and Line N-87-20 as sub plot factor at three replications were applied. Evaluating characteristics were included of the number of secondary spikes, the weight of main and secondary spikes, the contribution of main and secondary spikes, seed yield per plant and plot, length of main spike and the height of plant. The results of analysis of variance showed that genotypes had significant different on all investigating characteristic, while the effect of factor density was significant only for the weight of the spikes, yield per plant and plot and the length of main spike. None of the characteristic was not affected by the interaction of genotype  density. Based on the results, density and genotype had important effect on seed yield of the genotypes, however the effect of genotype was more than density. Mean comparison of the genotypes showed that secondary spikes had more contribution in the grain yield. In molecular experiment, SSR marker namely Xgwm136 associated to gene tin (tiller inhibition gene) was tested. Evaluation of the PCR product of this marker showed that the presence of band with the size of 300 to 350 base per is relating to reduction that tillering was confirmed in cultivar Tajan, Shirudi, Golestan, Darya and Gonbad genotypes that their low number of spikes had already been proven. So the efficiency of tin marker was proved for screening wheat for tillering.