LEAF-MACRONUTRIENT CONTENT AND YIELD IN GRAFTED MELON PLANTS - A MODEL TO EVALUATE THE INFLUENCE OF ROOTSTOCK GENOTYPE

The melon (Cucumis melo L.) cultivars Yuma and Gallicum were grafted o nto three rootstocks of Cucurbita maxima: Shintoza, RS-841 and Kamel. The two melon varieties left ungrafted were used as control. The plant s were grown under controlled conditions and fertilized constantly wit h both macro- and micronutrients. The total content of macronutrients (N, P, S, K, Na, Ca and Mg) and yield were determined in the aerial po rtion of both the control and grafted plants. A model was developed to determine the influence of the different rootstocks on the parameters analyzed, based on the differences between the control and grafted pl ants. Our results show that the use of the different rootstock genotyp es causes little change in the leaf content of macronutrients, princip ally in N and Na. On the contrary, root genotype determined the yield. Finally, we found a strong relationship between the variations in fol iar concentrations of N and Na and yield differences in grafted plants . (C) 1997 Elsevier Science B.V.