Horticultural and pathological experiments were carried out during the summer
seasons of 2004 and 2005 at the Experimental Farm of Mallawy Agriculture Research
Station, EI-Minia, Egypt and the Plant Pathology Dept., Fac. of Agric., EI-Minia
University, EI-Minia, Egypt. Eleven calcium salts (Dicalcium pyrophosphate, Calcium carbonate, Calcium
chloride, Calcium gluconate, Calcium phosphate, Calcium sulphate, Calcium
acetate, Calcium tartarate, Calcium hydrogen orthophosphate, Calcium oxide, and
Calcium lactate) besides control (tap water) [12 treatments], were applied
individually at concentration 2000 ppm by spraying the growing plants at the time of
tuberization after 45, 60 and 75days from planting on potato (Solanum tuberosum L.),
cv. "Nicola". Calcium chloride and Ca hydrogen orthophosphate gave significant
increase in the total tubers yield (ton/fed.) as well as No. of tubers/plant in both
seasons with insignificant differences between them. Yield percentage increase
reached to 16.55 and 13.44 with Ca chloride, 17.81 and 12.33 Yolth Ca hydrogen
orthophosphate in both seasons, respectively. Also, No. tubers /plant were affected
by the above treatments. In the two seasons, Ca hydrogen orthophosphate recorded
a significant increase in number of tubers (10.63 and 8.95 tubers/plant) compared to
11.44 tubers/plant with Ca oxide only, in the first season and 9.14 tubers/plant with
Ca chloride only, in the second season. Significant increase in the dry matter % was
found with Ca tartarate (21.57%) followed by Ca oxide (19.97%) in the first season,
but the difference between them were detected in the second season, was
insignificant compared with other Ca sources and the control treatments. Likewise, CaCI2 and Ca hydrogen orthophosphate increased the percentage; i.
e., of potato seed tubers 41.60 % and 39.67 % in the first season and 38.00 % and
38.28 % in the second. Differences did not reach to the level of significant. Foliar treatments with CaCl2/or Ca oxide gave the highest Ca (%) (averaged
1.40 %) in potato tubers and can be used to off set the shortage of Ca % in potato
tubers. Also the total phenolics content (TPC) differed among the potato tubers
treated with Ca sources and those treated with Ca oxide (164.0 )Jg/ml). Also it has
been found that their was a relationship between TPC and Ca (%),also, the anion
companion may play role. Among six potato cultivars, (Alpha, Diamant, Hermez, Lady Rosseta, Nicola
and sant') cv. Nicola was the highest susceptible one to soft rot disease followed by
cv. Diamant with insignificant difference between them. Ca-oxide was more effective
to protect potato tubers against dry rot disease (72.09 %).