This work was conducted at Laboratory of Tissue Culture and Experimental Farm, Faculty of Agriculture, Zagazig University, Egypt, during the period from 2002 to 2005, to produce tuber seeds of potato by using transplants produced from stem cuttings and tissue culture of Spunta, Diamant and Cara cultivars, also to study the effect of tuber seeds produced from transplants and local tuber seeds of three cultivars on the growth and yield.This work was divided into three experiments as follows5.1 FIRST EXPERIMENT: PRODUCTION OF TRANSPLANTS FROM STEM CUTTINGS AND TISSUE CULTURE PLANTLETS OF SOME POTATO CULTIVARSThis experiment was conducted during 2002 and 2003 seasons to produce transplants from stem cuttings and tissue culture plantlets. The obtained results could be summarized as follows:5.1.1 Production of transplants from stem cuttings5.1.1.1 Number of stem cuttings/mother planta. Spunta cv. plants recorded maximum number of stem cuttings/ plant followed by Cara and Diamant plant.5.1.1.2 Stem cuttings charactersa. Spunta and Cara cvs. plants significantly recorded the highest stem cutting length, number of leaves/stem cutting, fresh and dry weight/stem cutting. While Diamant cv. gave the highest number of rooted cuttings.b. Stem cutting length, number of leaves/stem cutting, fresh and dry weight/stem cutting and number of rooted cutting were significantly high with increasing IBA at 2500 ppm.c. Dipping stem cuttings in IBA at 2500 ppm significantly increased stem cutting length, number of leaves/stem cutting, fresh and dry weight/stem cutting and number of rooted cuttings for Spunta, Diamant and Cara cultivars.5.1.1.3 Transplants characters produced from stem cuttingsa. Spunta cv. gave the highest fresh and dry weight of foliage, while Diamant cv. recorded maximum survival percentage in the second season only.b. The transplant length, number of leaves/transplant, fresh and dry weight of foliage and roots /transplant and survival (%) were significantly high with IBA at 2500 ppm.c. Dipping stem cuttings in IBA at 2500 ppm recorded maximum transplant length, leaf number/transplant, fresh and dry weight of foliage and roots and survival percentage for all cultivars used.5.1.2 Production of transplants from tissue culture5.1.2.1 Plantlets charactersa. Spunta plantlets recorded maximum number of leaves/plantlet in the second season after acclimatization, fresh weight of foliage in both seasons before and after acclimatization.5.1.2.2 Plantlets dry weighta. There were no significant differences among Spunta, Diamant and Cara cvs. for dry weight of foliage and roots before and after acclimatization.It could be concluded that Diamant cv. recorded maximum number of rooted cuttings and survival percentage. Diamant and Cara cvs. recorded maximum survival (%) in vitro plants. Also, dipping stem cuttings in IBA at 2500 ppm recorded maximum survival percentage.5.2 SECOND EXPERIMENT: PRODUCING POTATO TUBER SEEDS BY USING TRANSPLANTS PRODUCED FROM STEM CUTTINGS AND TISSUE CULTURE PLANTLETSThis experiment was conducted 2002/2003 and 2003/2004 seasons to produce tuber seeds from transplants produced from stem cuttings and tissue culture. The obtained results could be summarized as follows:5.2.1 Plant Growth5.2.1.1 Morphological charactersa. Spunta cultivar gave the highest number of leaves and number of branches /plant.b. Plants produced from tissue culture recorded the tallest plant, while plants produced from stem cuttings recorded maximum number of branches/plant.c. Plants produced from tissue culture for cv. Spunta were the tallest plants and number of both main stems and branches/ plant, while plants produced from stem cuttings for cv. Spunta recorded maximum values of number of leaves / plant.5.2.1.2 Fresh and dry weighta. Spunta and Cara cvs. recorded maximum total fresh weight, dry weight of leaves, dry weight of aerial stems and total dry weight /plant , while Diamant cv. recorded minimum total dry weight/ plant .b. Plants produced from stem cuttings transplants gave higher total fresh weight, dry weight of leaves, dry weight of aerial stems and total dry weight/plant compared to those produced from tissue culture transplantsc. Plants of Spunta cv. produced from stem cuttings transplants were the best treatment which recorded maximum total fresh weight, dry weight of leaves, dry weight of aerial stems and total dry weight/plant .5.2.2 Photosynthetic Pigmentsa. Cara cv. recorded the highest concentration of chlorophyll a, b, total (a+b) and carotenoids in leaf tissues followed by Diamant cultivar.b. Plants produced from stem cuttings transplants gave higher concentration of chlorophyll a, b, total (a+b) and carotenoids in leaves tissues compared to those produced from tissues culture.c. The plants of Diamant or Cara cvs. produced from stem cuttings transplants gave the highest chlorophyll a, b, total (a+b) and carotenoids content in leaf tissues of potato.5.2.3 N, P and K Contentsa. Spunta cultivars significantly gave the highest values of N and P contents in stems, and P content in leaves.b. Plants produced from stem cuttings gave higher K content in leaves and stems, while plants produced from tissue culture gave higher N content in leaves and P content in leaves and stems.c. Plants of cv. Spunta produced from tissues culture recorded the highest N and P contents in stems, P contents in leaves, while plants of Cara cv. produced from tissues culture and produced from stem cuttings gave the highest K content in stems and leaves.5.2.4 Total Uptake of N, P and Ka. Spunta cv. recorded maximum N and P total uptake by plant and Cara cv. recorded maximum values of K total uptake by plant.b. Plants produced from stem cuttings transplants gave higher N and K total uptake by potato plants compared to those produced from tissue culture.c. Plants of Spunta cv. produced from stem cuttings transplants recorded maximum N and K total uptake, also the plants of Spunta cv. produced from tissue culture transplants recorded maximum P total uptake.5.2.5 Yield and its Componentsa. Diamant cv. recorded maximum number of tubers less than and above 10 gm /plant, yield of tuber above 10 gm /plant and /fed and total yield/feddan. On the other hand, Spunta cv. recorded maximum average tuber weight less than and above 10 gm.b. The plants produced from stem cuttings transplants gave the highest average tuber weigh above 10 gm and yield of tubers above 10 gm /plant and /fed and total yield /feddan compared to the plants produced from tissue culture transplants. The plants produced from tissue culture transplants produced maximum number of tubers less than and above 10 gm /plant.c. Diamant cv. produced from stem cuttings transplants gave the highest yield of tubers above 10 gm/plant and /fed. Diamant plants produced from tissue culture transplants gave the highest number of tubers less than and above 10 gm /plant, while Spunta cv. produced from stem cuttings transplants gave the highest values of average tuber weight less than and above 10 gm.5.2.6 Tuber Qualitya. Diamant cv. recorded maximum starch (%), carbohydrates (%) and dry matter (%), while Spunta cv. recorded maximum total sugar (%) in tubers.b. Plants produced from stem cuttings transplants gave the higher values of starch (%) and carbohydrates (%) in tubers.c. Diamant cv. produced from stem cuttings transplants recorded maximum starch (%), carbohydrates (%) and DM (%), while Spunta cv. plants produced from stem cuttings transplants recorded maximum total sugar(%).It could be concluded that potato plants produced from stem cuttings recorded maximum tuber seeds yield/plant and/fed for Diamant, Cara and Spunta cultivars, compared to those from tissue culture.5.3 THIRD EXPERIMENT: COMPARING THE TUBER SEEDS PRODUCED FROM TRANSPLANTS WITH LOCAL TUBER SEEDS PRODUCED FROM SUMMER CROPThis experiment was conducted during summer seasons of 2004 and 2005 to compare the yield of three sources of tuber seeds (tuber seeds produced from stem cuttings, tissue culture plantlets and local seed tubers) . The obtained results could be summarized as follows:5.3.1 Sprout Numbera. Diamant and Cara recorded maximum number of sprout/tuber followed Spunta cv.b. Local seed tubers gave the highest sprout number/tuber followed seed tubers produced from stem cuttings.c. Local tuber seeds or tuber seeds produced from stem cuttings of Diamant and Cara cvs. recorded maximum sprout number /tuber.5.3.2 Plant Growth5.3.2.1 Morphological charactersa. Spunta cv. were the tallest plants and gave the number of branches/plant, while Cara cv. recorded maximum number of both leaves and main stem/plant.b. The plants produced from local tuber seeds were the tallest plants, and gave the highest number of leaves, main stems and branches/plant.c. Spunta plants produced from local tuber seeds or tuber seeds produced from stem cuttings recorded the tallest plant and gave the highest and number of branches/ plant, while Cara plant produced from local tuber seeds or tuber seeds produced from stem cuttings recorded maximum number of both leaves and main stems/plant.5.3.2.2 Fresh and dry weighta. Cara cv. recorded maximum fresh weight/plant, dry weight of leaves, aerial stems and total dry weight/plant.b. Plants produced from local tuber seeds recorded maximum total fresh weight/plant, dry weight of leaves, aerial stems and total dry weight/ plant.c. Cara plants produced from local tuber seeds or tuber seeds produced from stem cuttings gave the highest total fresh weight/ plant, dry weight of leaves, aerial stems and total dry weight/ plant5.3.3 Yield and its Componentsa. Spunta cultivar gave the highest average tuber weight, followed by Cara cultivar.b. Plants produced from local tuber seeds recorded maximum tuber number/ plant, average tuber weight, yield / plant and yield/feddan.c. Spunta, Diamant and Cara plants produced from local tuber seeds or tuber seeds produced from stem cuttings recorded maximum tuber number/plant, average tuber weight, yield/ plant and feddan compared with the other treatments.5.3.4 Tubers Qualitya. Diamant cv. gave the highest carbohydrates and dry matter % in tuber, while Spunta cv. gave the highest total sugar (%) in tubers.b. The plants produced from local tuber seeds gave the highest values of starch, carbohydrates and DM%c. Diamant plants produced from local tuber seeds recorded maximum starch (%), carbohydrates (%) and DM (%).It could be concluded that plants produced from local tuber seeds or tuber seeds produced from stem cuttings gave the highest sprout number/tuber, tuber number/plant, average tuber weight, yield/plant and per feddan for Spunta, Diamant and Cara cultivars.