Performance of wild watermelon (Citrullus lanatus L.) in response to population density and mulch.

Abstract

The wild watermelon, Citrullus lanatus L. was among the most important foodstuffs to a number of African communities, until the colonists introduced their own foodstuffs in a process that was highly supported by the laws of the time. However, there is now a growing realization by government and other stakeholders of the importance of indigenous crops (including the wild watermelon) as substitute food stuff to improve food security. Wild watermelon is an adaptable crop, which can contribute to food security as it has a potential for commercialization. However, there are no records on the production of wild watermelon with reference to optimum planting density and the effects of mulch on the growth and development of the crop. To investigate this issue, which the smallholder farmers are faced with, a study that designed to (a) determine the effects of population density on growth and yield of wild watermelon and (b) investigate the effects of mulching on growth and yield of wild watermelon under field conditions. The study was undertaken over two seasons during which two different types of propagules, namely seed and seedlings, were used. A field study of wild watermelon establishment and yield using seeds and seedlings to compare the effects of different population densities (3000, 6000, 9000 and 12000 plants/ha) and mulching rates (0, 2.5 and 5 t/ha) based on the availability of grass on soil water, temperature, vine length (height), number of branches and leaves per plant, fruit number, total yields, fruit size and weed distribution was conducted at Dohne Agricultural Development Institute (Lat-32.52521; Long – 27.46119, alt. 907 m above sea-level) over a two year period ( 2009 – 2011 growing season). Results on data collection and analysis of growth and yield parameters are that: When seed was used as means of propagation, there were significant effects (p 0.05) of mulching and population density, on soil temperature and volumetric water content. However, no significant differences were found with regards to vine length, number of branches and leaves per plant. Concerning yield, there were no significant differences recorded on any of the measured parameters in response to mulch. Yet, with population density, significant differences were noted on fruit number per hectare and total yield at p 0.05. The number of fruits and total yield per hectare increased as plant population increased, resulting in high yields to range from 9000 -12 000 plants per hectare with both seed and seedling propagules used during the study period with or without mulching. Seedling propagules were associated with differences in soil temperature and volumetric water content with regards to mulching and population density (p 0.05). Results obtained from this study in both years, revealed that yield is more influenced by plant population density than by mulching. Mulching has been found to be ineffective as far as growth and yield are concerned, but it was found to influence soil temperature and volumetric water content.