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The use of healthy planting material is an important prerequisite for controlling destructive viral diseases in potato production. Virus elimination methods such as meristem culture and thermotherapy are usually used to produce the nucleus stock of healthy planting material. Here, we report a new technique of electrotherapy for elimination of two potyviruses, Potato virus A (PVA), and Potato virus Y (PVY), from potato plants. Electric currents of 15, 25 and 35 mili Ampers for 10 to 20 minutes were used for eliminating the combination of PVA and PVY in six potato cultivars. An electric current of 35 mili Ampers for 20 minutes was the most effective electrotherapy treatment for eliminating these two viruses. Responses of potato genotypes to electrotherapy were significantly different. Regenerations of electrotherapy treated plantlets in cultivars Lady Roseta and Banaba were 70.8 and 66.6 percent respectively, while these were approximately 54 to 58 percent for cultivars Olimpia, Agria, Desirea and Clone 69. Virus free plantlets were successfully produced in the potato cultivar Lady Roseta. However, in other cultivars examined in this study, electrotherapy resulted in drastic reduction of virus concentration but not total eradication of the virus infection from plant tissues.

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Developments in the oil contracts of countries indicate that most countries have abandoned the use of service contracts only and resorted to the contract model of production sharing contracts and new concessions, or by modifying, have driven their contract models to a variety of partnership contracts. However, this study shows that although many legal efforts have been made in Iran and Iraq to use this contract model, but the lack of clear law in this regard has led to the reform process of oil contracts leading to the implementation of models of long-term service contracts. The results of comparing the economic evaluation of Iranian petroleum contracts with service contracts and production sharing contract in Iraq show that the production sharing contract has higher economic efficiency, while creating the necessary incentives for the contractor to implement risky projects, in various economic conditions creates greater alignment between the interests of the parties to the contract, establishes a more efficient and equitable distribution of technical and economic risks between them, which is an important factor for the commitment of the parties to the implementation and termination of the contract. Therefore, it seems that due to the prevailing conditions in the oil market, including competition and declining trends in oil prices the use of the contract model of production sharing contract, at least for fields with difficult conditions and common fields, is a solution, but to use it like other countries, more effective legal measures such as the enactment of a law is essential.