Two field experiments were carried out during the summer seasons of 2005
and 2006 on potato cv. ( Spunta) in clayey loamy soil at EI-Baramoon Res .Station,
Mansoura, Dakahlia Governorate, Egypt to study the effect of soaking the imported
potato seed tubers in growth regulators i.e GA3 and IJ.A and their combinations at
different concentrations on vegetative growth parameters, tubers yield and its
components, tubers quality and some chemical contents of potato tubers. The results showed that soaking application of seed tubers in mixture of (GA3
+ IAA) at concentrations of (5+3 ppmrL for 10 minutes before planting was very
effective on the plant stand (%) at 21 and 28 DAP. The plant height (cm),number of
main stems / plant, fresh weight offoliagelplant (g) and dry weight of foliage (%) at 90
DAP were increased significantly compared with control and the other treatments in
both seasons. The medium tubers size percentage (35 - 65 inrn) ,number of
tubers/plant and total tubers yield of the 2 nd season (tons/fed), as well as dry
matter ( % ) , starch(%) , N, P and K contents in tubers at harvest were also
significantly increased. Small tubers size percentage (>35 mm) , total tubers yield of
the 1^s1 season, specific gravity and the micronutrients concentration in tubers (Fe, Zn
and Mn) at harvest were not affected significantly by different treatments during the
study seasons of 2005 and 2006 . Results revealed that soakin!! application of seeds tubers in mixture of (GA3 +
IAA) at concentrations of (5+3 ppm)' for 10 minutes before planting led to increase of
vegetative growth parameters, improvement of tubers quality and tubers yield and its
components in compared with the control and the other treatments . Applying this
treatment may help in solving the late sprouting problem of seed tubers in the
decreased soil of relative humidity by soaking the seeds in the previous treatment and
planting its immediately, in addition to produce more yield of medium tubers size
which are used as seeds for the following seasons (fall, winter and summer) .