Effects of Rootstocks on Some Growth Parameters, Phosphorous and Nitrogen Uptake Watermelon under Salt Stress

The uptake of phosphorous (P) and nitrogen (N) and some growth parameters of watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] cultivar 'Crimson Tide', grafted on gourd rootstock (Lagenaria siceraria) landraces and Cucurbita maxima, grown under five different saline conditions for 30 days were investigated. Salinity stress was induced by continuous irrigation with saline water having electrical conductivity (EC) of 0.5, 4, 8, 12, and 16 dS/m. Grafted watermelons showed better growth performance than non-grafted ones. Nutrient uptake was significantly affected by rootstocks and salinity levels. Salinity stress has resulted in an increase in P content of shoots as much as two fold. Total N uptake by shoots of both non-grafted and grafted watermelon on gourds gradually decreased above 8 dS/m salinity. This investigation showed that grafted plants had a better performance than the non-grafted watermelon cultivar. Therefore, gourds, especially those of Lagenaria type, may be used as a rootstock for watermelon under saline conditions.