Alzahraa Mohsen Abd El-wahab creator preparation. Sahar Sameh Taha thesis advisor. Ahmed Abdel-Wahab Ahmed thesis advisor. Ahmed Mohamed Magdy Gabr thesis advisor. text theses ua 2025 monographic eng ara 109 pages : illustrations ; 25 cm. + CD. This study was conducted to evaluate whether organic fertilization alone or with some ameliorative substances could replace mineral fertilization in minituber potato production to increase the quantity and quality of two cultivars (Cara and Hermes) of potato minituber produced from in vitro. Two pots experiments were conducted at the greenhouse of the Regional Research Center located in New Vally Governorate during the winter seasons of 2021/2022 and 2022/2023 in Egypt. The experiment included twelve treatments: 1- 100% compost; 2- 100% seaweed; 3- 100% compost + vinase; 4- 100%seaweed +vinase; 5- 50%compost +50% NPK; 6- 50%seaweed +50%NPK; 7- 25%compost +75% NPK + vinase; 8- 25%seaweed +75%NPK+Vinase; 9-75 kg K2O/ fed; 10-100kg K2O / fed; 11- 120kg K2O/ fed and 12-25%compost+75 % NPK (control). The treatments were arranged in completely randomized blocks design with three replicates. The results indicated that plant height, average minituber weight, minituber weight/pot and starch % in both seasons, chlorophyll reading in the first season as well as leave area in the second season were significantly higher in Cara cultivar than Hermes cultivar, whereas shoot weight in both seasons, chlorophyll reading in the second season as well as stem number of potato plant only in the first season were significantly higher in Hermes cultivar than Cara cultivar. On the other hand, the treatment of 120 kg K2O caused a significant increment of plant height, leaf area, shoot weight, stem number starch % and chlorophyll reading, 90 DAP, followed by 100 kg K2O. Moreover, the mixture among 25% compost+ 75%NPK + vinase gave the highest values of tubers number, average minituber weight and minituber weight/pot. هدفت الدراسة إلى تقييم استبدال التسميد المعدني بالتسميد العضوي أو بمزيج من المواد المُحسّنة (مثل الفيناس) لإنتاج درنات بطاطس صغيرة لصنفي "كارا" و"هيرميس" من المزارع النسيجية. أُجريت التجربة داخل صوب بمحافظة الوادي الجديد خلال موسمي 2021/2022 و2022/2023، وشملت 12 معاملة مختلفة بين التسميد العضوي والمعدني ومحسنات النمو. أظهرت النتائج تفوق الصنف "كارا" من حيث صفات الدرنة والنشا، بينما امتاز "هيرميس" في النمو الخضري. وحققت معاملة ٢٥٪ سماد عضوي + ٧٥٪ NPK + فيناس أعلى إنتاجية وجودة. تُوصي الدراسة باستخدام تلك التركيبة لتحسين إنتاج البطاطس وتقليل الاعتماد على التسميد المعدني specialized by Alzahraa Mohsen Abd El-wahab ; Supervisors Dr. Sahar Sameh Taha, Dr. Ahmed Abdel-Wahab Ahmed, Dr. Ahmed Mohamed Magdy Gabr. Thesis (M.Sc)-Cairo University, 2025. Bibliography: pages 83-108. Issues also as CD. Text in English and abstract in Arabic & English. Fertilizer الأسمدة Solanum tuberosum compost seaweed vinasse potassium growth yield بطاطس سماد بوتاسي 631.8 EG-GICUC 260304 20260312101340.0 eng