Abstract:
Agronomic biofortification is the deliberate use of mineral fertilizers to increase the
concentration of a target mineral in edible portions of crops to increase dietary
intake of the target mineral. Globally, increased dietary intake of potassium (K)
is becoming a part of the strategy to address hidden hunger and related noncommunicable diseases such as hypertension and cardiac disorders. This study
aimed at demonstrating the efficacy of increasing the concentration of K in the
edible portions of three commonly consumed but underutilized solanacea
vegetables (Solanum aethiopicum, S. macrocarpon and S. torvum) in Ghana. The
effects of different types and rates of K fertilizer application on the leaf- and
fruit-K contents of the vegetables, as well as the K loss between the raw and cooked fruits were investigated. Five levels of each of three types of K fertilizer
(liquid drench of potassium chloride, granular Muriate of potash and Sulphate of
potash) were applied to each of the three field-grown vegetables. Yield data were
collected and the fruits and leaves were analysed for the content of K, N, P, Ca,
Fe, Zn and Cu. The results showed the rate of fertilizer application had
significant effect on the yields of S. aethiopicum and macrocarpon but the yield
of S. torvum was significantly affected by type, rate and interactive effect of type
and rate of fertilizer application. Fruit K concentrations were greatest for S.
aethiopicum (2130 mg K kg1 DW) and S. torvum (1883 mg K kg1 DW) with
liquid KCl but with Sulphate of Potash for S. macrocarpon (1801 mg K kg1
DW). There were higher K concentrations in leaves than in fruits of all the
vegetables. Household cooking of the fruits resulted in the retention of over 70%
of the K content in the raw fruits. Potassium fertilization increased the Ca, Fe,
and Zn contents of S. aethiopicum and S. torvum. It is concluded that agronomic
biofortification may be a useful strategy to increase K intakes and other
important elements (e.g. Fe and Zn) in the vegetables studied
