s. a. sadat-noori

Ajowan is an important medicinal plant that grows mainly in arid and semi-arid regions of the world. To evaluate salinity tolerance of 25 Iranian ajowan ecotypes, three-step screening was conducted at germination, seedling, and adult plant growth stages using 0, 50, 100 and 150 mM of NaCl. The significant effects of salinity were observed at the three studied growth stages of ajowan ecotypes. Germination percentage, seed vigor, and biomass dry weight of investigated ecotypes decreased with the increase in NaCl levels. Different responses were observed among ajowan ecotypes in terms of activity of antioxidant enzymes of catalase and peroxidase, with the increasing salinity stress levels .Under the salinity stress, the proline content increased in the majority of the investigated ecotypes. Salinity stress had adverse effects on single plant seed yield and yield components. Results of the calculated correlation coefficient and path coefficient analysis showed that activity of catalase antioxidant enzyme and 1,000-seed weight were the most important characteristics that can be suggested as selection criteria for seed yield of ajowan under salinity stress conditions. The overall results suggest that nine Iranian ajowan ecotypes including Arak, Felaverjan, Ghoom, Hamedan, Karaj, Ghaen, Tehran, Yazd, and Shiraz were the salinity-tolerant ecotypes.

Melon is an important crop cultivated in moderate climate regions of the world. One of the most important diseases of this plant is vascular wilt caused by Fusarium oxysporum f.sp. melonis (Fom). The infection of farm with this pathogen can result in huge loss of yield and fruit quality of melon around the world. Genetic improvement for resistance is the best way of control of this disease. Up to now four races of 0, 1, 2 and 1,2 have been reported among which race 1 is more versatile and dangerous than other races especially at the north part of the country. Land races such as Saveh, Rish-baba and Tile-torogh are susceptible to this race. In this research the resistance gene was transferred from Isabelle, a resistant cultivar to susceptible varieties via marker assisted backcrossing. The screening of plants in BC1F1 and BC2F1 generations was carried out using artificial inoculation. Single dominant gene of Fom-2 induces resistance toward race 0 and 1. This gene has been sequenced and there are differences between susceptible and resistant allele. In order to verify the resistant plants survived after artificial inoculation in BC2F1, the plants were genotyped by SCAR marker. The resistance of most plants was verified however there were some susceptible plants among them implying the shortcomings of artificial inoculation method and more strength of molecular method. The verified plants were crossed to recurrent parents to produce BC3F1 generation. Considering acceptable yield and fruit quality of donor cultivar and evaluation results of BC2F1 it seems that no more back crossing is needed and with the selfing of BC3F1 plants new homozygote resistant varieties will be produced.
The screening of plants in BC1F1 and BC2F1 generations was carried out using artificial inoculation. Single dominant gene of Fom-2 induces resistance toward race 0 and 1. This gene has been sequenced and there are differences between susceptible and resistant allele. In order to verify the resistant plants survived after artificial inoculation in BC2F1, the plants were genotyped by SCAR marker. The resistance of most plants was verified however there were some susceptible plants among them implying the shortcomings of artificial inoculation method and more strength of molecular method. The verified plants were crossed to recurrent parents to produce BC3F1 generation. Considering acceptable yield and fruit quality of donor cultivar and evaluation results of BC2F1 it seems that no more back crossing is needed and with the selfing of BC3F1 plants new homozygote resistant varieties will be produced.