This paper reports on a debate on intriguing propositions relating to the scientific, agronomic, societal and economic impact of the BIOEXPLOIT project, focusing on late blight resistance in potato. It discusses (i) whether identifying pathogen effectors will facilitate selecting durable R genes, (ii) whether breeding for durable late blight resistance requires deploying Rpi (for Resistance to P hytophthora i nfestans) genes, (iii) whether breeding strategies and cultural practices determine the durability of new resistance genes, (iv) whether marker-assisted breeding for Phytophthora infestans resistance is already in the stage of adoption, (v) to what extent genetically-modified organism technology can advance realizing late-blight resistant potato cultivars, and (vi) whether modifying R genes will result in novel broad spectrum resistance.

There is concern that modern cultivars and/or agronomic practices have resulted in reduced concentrations of mineral elements essential to human nutrition in edible crops. Increased yields are often associated with reduced concentrations of mineral elements in produce, and a number of recent studies have indicated that, when grown under identical conditions, the concentrations of several mineral elements are lower in genotypes yielding more grain or shoot biomass than in older, lower-yielding genotypes. Potato is a significant crop, grown worldwide, yet few studies have investigated whether increasing yields, through agronomy or breeding, affects the concentrations of mineral elements in tubers. This article examines the hypothesis that increasing yields, either by the application of mineral fertilizers and/or by growing higher-yielding varieties, leads to decreased concentrations of mineral elements in tubers. It reports that the application of fertilizers influences tuber elemental composition in a complex manner, presumably as a consequence of soil chemistry and interactions between mineral elements within the plant, that considerable variation exists between potato genotypes in the concentrations of mineral elements in their tubers, and that, like in other crops, higher-yielding genotypes occasionally have lower concentrations of some mineral elements in their edible tissues than lower-yielding genotypes.

This research was carried out in greenhouse of Mohaghegh Ardabili University by using split plot experiment basis of completely randomized block design. In this project ,obtained micro tuber from healthy laboratory plantlets of potato (private section) were planted in greenhouse condition during 2006.Microtubers were sprouted (amount of 0.5 cm) at the planting time and they were not necessary for presprouting of planted micro tubers. In this research the cultivars were used as main plot in 2 levels (Savalan and Agria) and micro tuber sizes (weight) were used as sub plot in 6 levels of 50 mg, 50-100 mg ,100- 150 mg,150-200 mg,200-250 mg and one gr tuber size (check) .Agronomic practices were uniformity used for all treatments during planting and plant growth and development stages. The studied agronomic characters such as wet tuber yield per unit area and hectare, emergence percent ,flowering date, stolon and tuber initiation dates, number of tuber per plant, number of main stem per plant, mean stem diameter and stem height were recorded during plant growth and developments. Analysis of variance was done by using the SAS statistical software and the comparison of treatments mean of mentioned above characters were done on the basis of LSD 5%.Savalan in 200-250 mg with production of 4.755 kg tuber per m2 relative to compare with Agria and other factors of micro tuber weight levels had better conditions between 2 studied cultivars. There were significantly differences between main effect of cultivars in analysis of variance table and all of studied characters were better in Savalan, by contrast to Agria. So it caused the very significantly increasing of wet tuber yield in Savalan.