RESPONSE OF POTATO PLANTS FOR DIFFERENT SOURCES OF POTASSIUM WITH DIFFERENT FOLIAR RATES OF BORON AND MOLYBDENUM

Two field experiments were conducted during the two successive fall
seasons of 200212003 and 2003/2004 on potato cv. Spunta at EL-Zahraa village,
Mansoura, Egypt, to study effect of two potassium sources (sulphate or chloride) at
the recommended rate and so different foliar spraying rates of boron (50 and 75 ppm)
or/plus molybdenum (25 and 50 ppm) twice at 60 and 75 DAP, in addition to their
interactions on vegetative growth characters, tubers quality, tuber minerals content
and total tuber yield.
The results indicated - generally - that K2S04 application was more effective
than KCL on the vegetative growth parameters, tuber quality characters and the yield
and its components. Application of K2S04 led to higher tubers yield production (8.95-
11.33 %) than KCL application during the 1^st and 2^nd seasons, respectively.
Foliar spraying of potato plants with (8 at 75 ppm + Mo at 50 ppm) twice at
60 and 75 DAP was significantly increased most vegetative growth parameters and
led to in improve the tuber quality parameters i.e. dry matter, starch, specific gravity
and the protein of tuber, as well as, the tuber weight and total tuber yield compared
with the other treatments in both seasons.
In general, application of K2S04 to the soil and spraying potato plants twice
at 60 and 70 DAP with boron and molybdenum together at rate of (75 ppm and 50
ppm, respectively) recorded maximum values of plant growth parameters, improved
tubers quality characters and highest tuber yield/fed. On the other hand, recorded
lowest concentration of nitrate in potato tuber was produced.