Abstract:
Sugar content is the key to mango quality and growers are constantly seeking methods to optimize it. In
this study, fructose, glucose, sucrose, and maltose sugars were evaluated to determine how phosphorus and potassium
fertilizers in varying amounts could affect these sugar levels and how sunlight exposure effects fruit. The experiments
were conducted in the KALRO Orchard of Kiambu County, Kenya. Thirty-five healthy 7- to 8-year-old ‘Kent’ trees
were selected and divided into five treatment groups with five replicates each. Treatment with 1 kg, 2 kg P, K and
combined PK per tree resulted in a significantly higher fructose content than the control.
In contrast, neither 1 kg nor 2 kg P resulted in significantly higher glucose contents than the control. Combined PK
fertilizers at 0.5+0.5 kg per tree reduced fructose and increased glucose, sucrose, and maltose. A combination of
PK fertilizers at 1.0 +1.0 kg significantly increased only fructose, but not other sugars. Even after applying P and K
fertilizers, the position of the fruit canopy did not affect fructose, glucose, or maltose contents. However, there was a
trend towards a higher sucrose content in fruits exposed to sunlight (5.17 g/100 g) than in canopy fruits (2.29g/100g),
although this difference was not statistically significant. The same trend was observed for the other sugars. The t-test
revealed no significant differences between the two canopy positions (t = 1.01, p = 0.344). A significant difference
in sugar content (p < 0.05) between fruits harvested at different canopy positions suggests that fruits harvested at
different canopy positions did not ripen simultaneously.
Keywords: Fertilizer, Tree canopy, Mango, Sugars
