فهرست مطالب روح الله نیک فکر

Sesame is one of the oil plants that has been cultivated for a long time. Unfortunately, the low yield of sesame and the easier production of other oil seeds have caused less attention to be paid to the cultivation of this plant, so it is necessary to take action in the direction of producing high-yielding cultivars. Soil salinity is an essential factor that affects the growth, development, and productivity of almost all land plants, including sesame. Increasing the concentration of salt in the plant growth environment leads to an increase in Na+ and Cl- ions in plants and induces oxidative stress, osmotic stress, and ion toxicity. Seed germination and early seedling growth are critical stages in the plant life cycle that largely determine crop yield. In this experiment, the sesame plant was investigated in three stages: germination (germination indices), seedling (phenotypic characteristics of seedling, SOD, CAT activities, MDA and H2O2 content), and maturity stage. Therefore, 21 different sesame cultivars were studied for genetic diversity and heritability of traits. Also, the relationship between traits in three stages and the influence of morphological traits in the farm environment were measured. Cultivars were grouped using these traits, and cultivars tolerant and sensitive to salinity stress were identified. The cultivars studied were divided into two groups, and high-yielding genotypes such as Oltan, 159, Naz Chandshakhe, Yellowwhite, Maghan, 418, American, and Chinese were placed in one group. To obtain new recombinant, the genotypes of distant clusters are used as parents for the hybridization program. The use of selected traits in the sesame breeding program increases yield.

Sesame is one of the oldest products known to man to date. Sesame was a valuable crop in the ancient world due to its drought resistance, ease of oil extraction from seeds and oil stability. Iran is one of the arid and semi-arid regions of the world in terms of climate. In these areas, low and scattered rainfall and high evaporation usually cause the accumulation of salts in the surface layer of the soil. Therefore, the salinity of soil and irrigation water causes significant morphological, physiological and chemical changes. Excess salt, that is, more than plants need limits crop growth and production and can lead to plant death.

In this experiment, 20 sesame genotypes were grown in greenhouses. The experiment was performed as a factorial in a completely randomized design with three replications. 75 mM sodium chloride was dissolved per liter of water and the pots were irrigated with saltwater. Percent morphological traits loss index (PML) was calculated.

According to the results of analysis of variance and comparison of the mean interaction of cultivar × stress in all studied traits were significant. American and Yellow- White cultivars with 17927 and 14.07 g, respectively, the highest and 714 and Dezful with 2.43 and 2.07 g, respectively, the lowest yield under normal conditions, and Oltan and American cultivars, respectively, with an average of 963 8.8 and 7.34 g had the highest and Darab 1 and Dezful had the lowest yield under stress conditions with 0.92 and 0.71 g, respectively. In this study, clustering method was used to group and separate useful (high yield) and susceptible (low yield) genotypes based on different traits. The results showed that the studied genotypes were grouped based on morphological traits and yield reduction percentage index using standard data. The studied genotypes were divided into 3 groups. In the first group, Oltan, American, Chinese, Dashtestan 2, 369 and 418 genotypes with the highest yield among the genotypes were studied. The second group included Darab 1, 730 and Dezful genotypes and the third group included other genotypes. In the first group, it is desirable to distinguish high-yield genotypes with desirable traits and the lowest percentage of yield reduction under salinity stress conditions from other genotypes.

The results of this experiment showed that there is a favorable variation among the study population, especially a significant difference was observed between the performance of genotypes in both normal environmental conditions and salinity stress. Correlation analysis of traits showed that under normal conditions, number of seeds per plant, number of capsules per plant and 100-seed weight, and under salinity stress, number of seeds per plant, number of capsules per plant and single plant weight had the highest correlation with yield. In this experiment, the best salinity tolerant lines were Oltan, American, Chinese, Dashtestan 2, 369 and 418 genotypes. It is noteworthy that these genotypes had a more stable performance than others in both conditions, so they have stress tolerance genes and can be considered in future studies. Also Darab 1, 730 and Dezful genotypes were the most sensitive genotypes to salinity stress in this experiment.

In order to study the relationships among agronomic traits and yield components in some breeding lines of safflower (Carthamus tinctorius L)، this experiment was conducted in a randomized complete block design with three replications in 2009، at the Research Farm of Isfahan University of Technology located in Falavarjan، Isfahan، Iran. Twenty genotypes of safflower were planted in this experiment and days to emergence، days to the commencing of flowering، 50% flowering and maturity، plant height، branches/plant، percentage of infected capitulum to safflower fly، seed yield، capitula/plant، seeds/capitulum، 1000 seed weight، capitulum diameter، seed weight/capitulum and seed oil content were evaluated. The results of analysis of variance showed that there were significant differences among the genotypes for all of the studied traits، except for days to emergence. Genetic and phenotypic correlation coefficients showed that capitula/plant، seeds/capitulum and capitulum diameter were the most important seed yield components and they had the highest positive correlations with seed yield. However، seed weight showed negative genetic and phenotypic correlations with seed yield. Based on the regression analysis، capitula/plant along with capitulum diameter accounted for 66% and 74% of the seed yield variation، respectively. Path analysis showed that capitula/plant had the most positive direct effect on seed yield with no significant indirect effect through the other traits. Also، seeds/capitulum had a high direct and positive effect and considerable indirect effect via number of capitula/plant on seed yield.