International Journal of Horticulture, 2016, Vol.6, No.22, 1-14
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cracked fruit. Meanwhile cracked fruit may be due to attacks by animal pest and not varietal dependent, therefore
if properly managed, this variety may still perform well in late season crop.
The chemical and proximate composition of watermelon fruits showed that the nutritional quality differed among
the varieties and manure types. In particular, N, P, K, Ca, Mg, moisture content, crude fiber, ash content and
vitamin C contents of tested varieties differed significantly. In the rainy season crop, NPK enhanced the content of
N, P, K, moisture content, total solids and vitamin C in Charleston grey. Nitrogen content and moisture content in
Crimson sweet were enhanced by NPK application in addition to increases in K, Ca and Mg content in Sugarbaby
and moisture content and vitamin C in Kaolac. However, organo-mineral fertilizer (OMF) produced increases in N,
Ca, Mg and crude fiber in Anderson, P content in Kaolac, N and crude fiber in Sugarbaby and vitamin C only in
Charleston grey. The effects of NPK and organo-mineral fertilizer application on fruit nutritional (proximate)
quality of the varieties mentioned above may be probably due to the role of nitrogen in crop maturation,
flowering and fruiting (Indira, 2005, Agele et al., 2008). In the late season crop, NPK application enhanced the
nutritional content of Sugarbaby and Anderson and total solids. In the same vein, NPK enhanced P, K and Mg and
total solids in Anderson unlike the rainy season crop. This shows that N mineralization and availability for root
uptake may be hindered by heavy rainfall, hence the yield of late season crop. NPK application in the late season
increased P, Mg, total solids content in Charleston Grey, Ca and Mg, total solids and vitamin C in Crimson Sweet
and Mg, moisture content and vitamin C in Kaolac respectively. The fruit contents of P, Ca, crude fiber and
vitamin C content in Kaolac, P, total solids and vitamin C in Crimson Sweet, Ca and total solids in Charleston
Grey and Anderson and moisture content and vitamin C in Sugarbaby were enhanced by OMF application. In
rainy season crop, ash and crude fibre content were not enhanced by NPK application in the varieties. Vitamin C
content shows no response to manuring in Sugarbaby, Crimson Sweet and Anderson. Unmanured Anderson had
highest vitamin C content, which shows the non- response to manuring in the late season. It is noteworthy to say
that Anderson is recommended as best in terms of vitamin C content irrespective of manuring in both seasons.
This variety seems more nutritious without enhancement by manuring especially in the rainy season. The study
shows that the tested varieties of watermelon are high in mineral contents, which play important roles in man and
animals.
4 Conclusion
The The results of this study show that the water melon varieties tested responded differently in terms of growth,
yield and nutritional qualities to application of manure in both the rainy and late season. Charleston Grey variety
performed well in terms of growth (biomass) but produced poor fruit yield in the rainy season. Other varieties
like Kaolac and Anderson recorded high fruit yield components in the rainy season. Late season favored growth
and yield in Crimson Sweet variety and it is better adapted to the environmental conditions then. Varieties like
Kaolac adapted well in terms of growth and yield to both rainy and late season. For the rainy season crop, NPK
fertilizer significantly enhanced growth and yield characters of watermelon compared to organomineral (OMF)
fertilizer. NPK enhanced fruit size compared to control but recorded higher number of fruit disorders in both
seasons. Organo-mineral fertilizer application enhanced number of fruit rot over the control. However in some
cases the control produced significantly higher fruit weight over NPK and OMF. This result confirms that
watermelon at times does not have large fertilizer requirements and can be grown with little or more fertilizer. In
the rainy season, application of NPK and organo-mineral fertilizer enhanced performance of watermelon varieties
in terms of fruit yield and its components in varieties like Charleston grey, Anderson, Crimson Sweet and
Sugarbaby. Sugarbaby showed no record of fruit rot for all fertilizer types tested, which implies that Sugarbaby
performs best in both seasons and there is possibility of producing larger and heavier fruits when treated with
mineral fertilizers. The chemical and proximate composition of watermelon fruits showed that the nutritional
