Abstract:
Green chili (Capsicum annuum L.) is commercially grown as a spice crop in Sri Lanka.
Rapid changes in post-harvest quality and pre-harvest and post-harvest diseases are the
main problems in the green chili industry. Silicon (Si) application has shown many
beneficial effects on plant growth and disease control. The present study evaluated the
effect of soil application of Rice husk ash (RHA), a natural Si source on postharvest
quality of green chili, compared to the fungicide treated plants and non-treated control
plants. RHA was added to plants (2g/plant) starting at 10 days after seedling
establishment and continued up to 28 days at seven days intervals. Si accumulation in
leaves and pods were tested during the growth. Natural disease occurrence, changes in
chlorophyll content, pH, total soluble solids (TSS), Titratable acidity (TA), ascorbic acid
content, total phenolic content, peel color, visual quality rating (VQR), weight loss,
cuticle epidermal layer thickness, crude protein, crude fat, crude fiber, total ash, and
moisture percentage were measured in the harvested pods. Soil amendments with Si
significantly reduced the postharvest weight loss through delayed ripening and reduced
natural disease occurrence hence enhancing VQR (p < 0.05). Accumulated Si content in
leaves of the RHA treated plants was significantly higher (p < 0.05) than that of control
plants although the differences among the pods of different treatments were insignificant
(p > 0.05). RHA treatment increased the Crude Protein, ash, total chlorophyll, total
phenol content, and cuticle epidermal layer thickness significantly but did not affect other
physic-chemical parameters tested (p > 0.05). These results suggest that by using the preharvest soil application of RHA, the postharvest quality of green chili can be improved.
Enhanced Si content in leaves and increased phenolic content in pods may have some role
in Si-induced disease resistance and other quality parameters.
Keywords: Green chili, Rice husk ash, Post-harvest quality, Post-harvest disease, Si
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