Cne.nical fertilizers are commonly added to potato plants to produce high
yield although. the use of biofertilizers is more economical and much saving than the
use of inorganic fertilizers. which already raised the pollution of the environment. Therefore. this study was conducted in two successive summer seasons of
2000 and 2001 on potato cv. Spunta at Baramoon Experimental Farm, Dakahlia
Governorate. Egypt. to investigate the effect of vesicular-arbuscular mycorrhizal
(VAM) fungi and four levels of chemical phosphorous i.e., O. 25. 50 and 75 kg
P205/fed. as well as to study the interaction on growth, tuber yield and their
components of potato plant. Moreover. the contents of NPK in foliage, starch and
nitrate in tubers. The obtained results revealed that inoculation potato seed tubers with VAM
fungi before planting markedly increased vegetative growth, i.e .. plant height. foliage
fresh weighVplant. number of main stems/plant, foliage dry weight, total tuber yield
(ton/fed.), number of tubers/plant, tuber average weight. tuber dry matter/plant. NPK
contents in foliage and starch content in tubers while, the concentration of nitrate
decreased in tuber by using of VAM fungi during both seasons Vegetative growth (plant height, foliage fresh weighVplant, number of main
stems/plant) NPK and nitrate contents increased with increasing phosphorous
fertilizer at level 75 kg P₂0s/fed. while, higher value of foliage dry weight, total tuber
yield and its component (tuber average weight, tuber dry matter/plant), NPK and
nitrate contents in tuber treatment receiving 50 kg PzOs{fed.of P fertilizer. The positive interaction between VAM fungi and phosphorous levels on plant
height (in first season), total tuber yield and NP contents in foliage in the two
seasons. Generalty, the results indicated that inoculation potato seed tubers with VAM
fungi at the rate 12.5 kg/ton) before planting in addition to 50 kg P₂0s{fed. gave
higher total tuber yield/fed. and starch content in tuber. Thus inoculation with VAM fungi before planting raised the efficiency of P
fertilizer and would decrease the required rate to plants about by 25 %. Consequently
increase the productivity and improving quality of tuber, in addition to produce the
pollution of environment.