Abstract:
Mango (Mangifera indica L.) cv. TomEJC has utmost potential in export market due
to its unique quality. Post-harvest disease of mango such as stem-end rot can cause
considerable losses of fruits and could therefore be considered as a great threat to
local and export market. This disease is controlled by application of fungicides from
the time of flowering in cultivations where this disease is severe. However, the use of
fungicides could lead to hazardous effects such as oncogenic risks on the consumers.
Therefore, search for alternative measures for the management of stem-end rot
disease is essential. In this study, an attempt was made to find out the effect of preharvest application of KCl on controlling stem-end rot disease development of ripe
fruit. KCl at concentrations of 1 gl-1, 2 gl-1 and 4 gl-1 were sprayed on fruit when fruits
were immature. All fruits were bagged with paper bags and fruits were harvested
at the correct maturity stage. Then all fruits were inoculated with Botryodiplodia
theobromae mycelial plug and allowed for natural ripening. A significant difference
was observed in fruit length, fruit width and fruit volume in KCl- treated fruits when
compared to controls. Highest fruit volume was observed in 1 gl-1 KCl- treated fruits
and the lowest amount of total soluble solids was observed in 2 gl-1 KCl- treated
fruits. An increase in lightness and yellowness of peel color in KCl- treated fruits
when compared to control II (non-inoculated, non-treated) was evident, indicated by
increasing L*, b* and chroma values. However, no significant difference in hue values
of peel color was observed among treatments. Flesh color showed a different response
to treatments and no difference in chroma value was observed among treatments. The
highest L* value and hue value was observed in 2 gl-1 KCl- treated fruits. Incidence
and severity of stem-end rot was significantly decreased by 2 gl-1 KCl treatment
without drastically affecting the physico-chemical properties of fruits. Vast research
has shown that potassium and chloride fertility have been effective in reducing crop
injury from diseases. Different mechanisms such as nutritional effects, changes of the
Sabaragamuwa University Journal
Volume 14 Number 2; December 2015, pp 119-132
ISSN 1391-3166; eISSN 2386-2041
DOI : http://dx.doi.org/10.4038/suslj.v14i2.7700
120
host-pathogen environment and production of disease inhibitory compounds could
be some possible ways of action of both K and Cl in modifying disease resistance or
susceptibility. Since 2 gl-1 KCl was able to suppress stem-end rot disease development
in inoculated fruits, this concentration can be recommended as a field application to
control this disease in mango variety tested after repeating the same experiment at
different locations.
