Abstract :
The effect of sahne irrigation water containing NaCl or
Na2SO4 with and without CaSO4 application on the gram
yield, smut index and plant nutrient contents of two
intermediate smut-susceptible corn cultivars was investigated
in cemented plots containing sandy loam soil. The
plants were artificially infected and the disease severity
was rated. At the end of silking stage, the leaf Cl, Na
and Ca contents were detected and Ca/Na ratio was
calculated. At harvest, the grain yield of smut-free and
smutted plants was recorded. The results showed that
NaiSOi-treated plants had a greater yield advantage than
those exposed to NaCl-treatments. The inclusion of
CaSO4 was beneficial to both salinity types and improved
the yield potential. Similarly, smut susceptibility was
reduced by 10.8% for the Na2SO4-stressed plants, compared
with 22.7% for NaCl treatment. The comparable
reductions in disease severity associated with Ca supply
dropped to 33.0 and 17.0%, respectively, indicating the
beneficial contribution of a Ca supply on the mediating
disease reaction. Although the smut index was markedly
decreased as the leaf C! content increased in Ca-deficient
plants stibjected to saline irrigation water without Ca
supply, the increase in the Ca/Na ratio in plant tissue,
associated with supplemental CaSO4 application to each
salinity type, appeared to have an additive effect on smut
disease control and salt tolerance.
