This study was carried out at vegetables field of Horticulture and landscape department. College of Agriculture and Forestry. Mosul University. Iraq.. during spring season of 2011, to investigate the effect of three factors: water stress. calcium ion and two natural extracts Licorice. Soluamine in addition to three methods of application in some yield characters of potato (Solanum tuberosum L . cv .Latona) . The experiment includes 24 treatment ( 2 × 3 × 4 ) conducted in a Factorial Experiment within Split – plot system in a R.C.B.D Design. each treatment was replicated three times. The results could be summarized as follows: 1-Exposuing potato plants to water stress during the period of tubers formation and development caused a significant decrease in all yield characters traits. 2- Application of calcium. Licorice and soluamine extracts. significantly increased all yield characters as compared with control treatment. except the mean of tuber weight. 3- Application of calcium and two natural extracts (Licorice and soluamine) by to the soil caused a significant increase in tubers weight. plant yield and total yield as compared to (foliar application). while the tow others methods of application (adding to soil) and (foliar spray + adding to the soil) resulted in a significant increase in marketable yield as comparing with first method (foliar spray) 4- The interaction treatments among calcium. Licorice. soluamine extracts. and methods of application over drawn on reduction the damage effect of water stress in all study characters of the droughted plants.