Growth and Productivity of Some Sweet Potato Cultivars as Affected By Some Vitamins, Salicylic Acid and Plant Density Under Sandy Soil conditions

This work was carried out during summer seasons of 2008 and 2009 at El-Kassasin Hort. Res. Station, Ismailia Governorate, to study the effect of cultivar, plant density and their interactions, foliar spray with vitamin C, vitamin B1 and salicylic acid (SA) on the growth, yield and quality of sweet potato tuber roots under sandy soil conditions.Sweet potato cv. A-193 gave the highest total yield when planted at 48,000 plant/feddan followed by cv. Beauregard at the same plant density. Sweet potato cv. A-193 gave the highest oversized tuber roots yield percentage of the total yield (40.56 % as average of two seasons) when planted at 24,000 plant/feddan. Beauregard cv. gave the highest marketable tuber roots yield percentage of the total yield (69.84 % as average of two seasons) when planted at 48,000 plant/feddan and cv. Abees gave the highest culls tuber roots yield percentage of the total yield (15.54 % as average of two seasons) when was planted at 48,000 plant/feddan. Tuber roots produced from cv. Abees plants grown at 48,000 plant/feddan gave the highest sugars percentage followed by tuber roots produced from cv. A-193 plants grown at the same plant density. Also, tuber roots produced from cv. Abees plants grown at 48,000 plant/feddan gave the highest carotene content followed by tuber roots produced from cv. Beauregard plants grown at the same plant density. spraying sweet potato plants of cv. A-193 with Vit.C, Vit.B1 and SA at 100 ppm of each gave the highest total yield/feddan and marketable tuber roots yield of total yield (73.81 % as average of two seasons), also gave the highest contents of sugars and carotene in tuber roots.