EFFECTS OF VARIETY AND MANURE APPLICATION ON THE GROWTH, YIELD AND NUTRITIONAL QUALITY OF WATERMELON (Citrullus lanatus L.) IN AKURE, NIGERIA

Abstract

The effects of variety and manure application on the growth, yield and nutritional quality of watermelon (Citrullus lanatus L.) were investigated during the rainy and late cropping seasons of 2012. The study was conducted at the Teaching and Research Farm of the Federal University of Technology, Akure. The experiment each season was a factorial combination of five watermelon varieties and three manure types laid out in a randomized complete block design (RCBD) with three replications. The varieties were Crimson Sweet, Charleston Grey, Kaolac, Anderson and Sugarbaby, while the manures which were applied at 3 weeks after planting were organomineral fertilizer (OMF) (5t/ha), NPK fertilizer (200kg/ha) and an unmanured control. The watermelon varieties tested responded differently in terms of growth and yield components due to differences in their genetic composition or potentials. In the rainy season, Charleston Grey performed well in terms of growth (biomass) but produced poor fruit yield while Kaolac and Anderson recorded high fruit yield components. Late season favored growth and yield in Crimson Sweet, Kaolac also produced highest number of fruit per plant t in the late season, hence performed well as both rainy and late season crop in terms of fruit yield. Varietal performance on fruit quality in terms of number of rotten and cracked fruits per plant showed significant differences in fruit rots among varieties. In both rainy and late season, Charleston Grey and Kaolac produced the highest fruit rots and cracks per plant. The effect of manure application on growth and yield of watermelon showed no significant differences, however the effect of NPK fertilizer enhanced higher growth and yield over OMF and unmanured control in both rainy and late season crop. There were varied responses in growth and fruit yield characters of watermelon varieties to manure application as depicted by the interaction effect of variety and manuring on growth and fruit yield character of watermelon. In the rainy season crop, application of NPK and organomineral fertilizer enhanced fruit yield component of watermelon varieties (Kaolac, Anderson, Crimson Sweet and Sugarbaby). In the late season, application of NPK enhanced highest number of fruits per plant in Charleston Grey, highest mean fruit diameter and mean fruit weight per plant in Anderson. Sugarbaby performed best in both seasons, Charleston Grey is not adequately adapted to rainy season growing environmental conditions while Anderson when manured performed well as both rainy and late season crop. The chemical and proximate compositions of tested varieties differed significantly and were affected by manure application. NPK application in the rainy season enhanced fruit contents of N, P, K, moisture, total solids and vitamin C in most varieties except in Anderson. OMF produced increases in N, Ca, Mg and crude fiber in Anderson, P content in Kaolac, N and % crude fibre in Sugarbaby and vitamin C in Charleston Grey. NPK application in late season enhanced the nutritional (total solids) contents in all the varieties while OMF application enhanced fruit contents of P, Ca, crude fiber, vitamin C and total solids in some of the tested varieties. However, Unmanured Anderson had highest vitamin C content in the late season. Application of NPK to Sugarbaby in the late season crop enhanced its nutritional content. It is concluded that application of NPK and OMF fertilizer enhance growth, yield and nutritional content of watermelon varieties in both rainy and late season in the study area.