This experiment was carried out at the Agriculture Experimental Station, Faculty of Agriculture, Cairo University, Giza in two successive seasons 2006 and 2007. The aim of this research was to study the effect of planting distances between the plants and foliar spray with some micro-elements on the growth, yield and some chemical constituents of roselle plant.
The plants were sprayed with Zero (control), 90 and 180 ppm. (Fe + Mn + Zn together). The planting distances between the plants in this experiment were 40, 60 or 80 cm. There was constant distance between the rows (60 cm.). The obtained results can be summarized as follows:
The foliar spray with micro-elements at the rates of 90 or 180 ppm. increased all the recorded characters of the growth, yield and chemical constituents as compared with the control treatment. The highest values of number of branches/plant, stem diameter, number of fruits/plant, yield of fresh fruits/plant, yield of fresh and dry sepals/plant and total soluble solids% were obtained with foliar spray by micro- elements at 90 ppm.
Also, the highest plant height, number of leaves/plant, chlorophyll A, B, carotenoids, total carbohydrates %, anthocyanin content, pH value, Fe, Mn and Zn contents were obtained with foliar spray with micro-elements at 180 ppm. As well as the greatest yield of dry seeds/plant was obtained with foliar spray by micro- elements at 90 ppm. in the first season and 180 ppm. in the second season. The lowest values of all recorded parameters of growth, yield and chemical constituents were obtained with the untreated plants with micro-elements (control).
The highest values of all recorded characters of the growth, yield and chemical constituents were obtained with the wider space between the plants (80 cm.) followed by medium space (60cm) then narrow space (40 cm.).
On the other hand, the opposite response occurred with plant height which the tallest plants were produced from the narrow distance between the plants (40 cm.).
The interaction between micro- elements at 90 or 180 ppm. and different planting spaces increased all the recorded parameters of the growth, yield and chemical constituents as compared with the interaction between micro-elements at zero (control) and all different planting distances in most cases.