EFFECTS OF DIFFERENT ROOTSTOCKS ON PLANT GROWTH, YIELD AND QUALITY OF WATERMELON GROWN IN GREENHOUSE

This study was carried out to determine the effects of different rootstocks on plant growth, yield and quality of watermelon. Cultivar Crimson Tide was grafted on three interspecific squash (Cucurbita maxima × C. moschata) hybrid rootstocks, namely RS841, Nunhems 9075 and Maximus (AG 1355) and two bottle gourd (Lagenaria siceraria) rootstocks, namely Macis and Argentario and compared with non-grafted and self-grafted ones. Plants were grown in perlite as open system. The seedlings were transferred into the greenhouse on 13.03.2009 and they were planted as one plant per container with a plant density of 1.16 plant m-2. The experimental design was randomized blocks with 3 replicates. Water and nutrient requirements of plants were supplied with complete nutrient solution via drip irrigation. Parameters related to plant growth, yield, fruit quality were determined. The highest yield was obtained from Maximus which was 89.9 and 66.3% higher than non-grafted and self-grafted treatments, respectively. Plant fresh and dry weights, length, fruit size, number of seeds, total soluble solids, EC and pH of fruit juice increased with the use of rootstocks. Pulp color in grafted watermelons was redder then fruits on non-grafted and self-grafted plants. Some of the correlation coefficients were found significant; especially total yield was positively correlated with fruit weight and length, seed number, shoot and root fresh and dry weights, stem length and scion diameter. It was concluded that grafting improved plant growth, yield and some quality parameters. However, the performance of rootstock depends on the genotype of either rootstock or scion. C. maxima × C. moschata hybrids (RS841, Nunhems 9075 and Maximus) could be used for Citrullus lanatus ‘Crimson Tide’ with higher performance while Lagenaria siceraria rootstocks (Argentario and Macis) was not found appropriate for that cultivar.