The Role of Compost, Amino Acids, Silicon and Seaweeds Extract in Enhancing the Growth, Yield and Active Ingredients of Roselle Plants

This investigation was conducted at the Experimental Farm Faculty of Agriculture, Al-Azhar Univ., Assiut during the two successive seasons of 2018 and 2019 to determine the influence of compost as organic fertilization and foliar Spray with stimulant substance namely (amino acids [tryptophan + methionine + phenylalanine], silicon and seaweeds extract), as well as their interactions on plant growth traits, sepals. yield / plant and fed. and active ingredients of roselle (Hibiscus sabdariffa, L.) C.V. "Sabahia 17" dark line plants. Compost was applied at 0, 8, 16 and 24 m³/ fed., and spraying the plants with the three examined stimulant substances as follows: control (no sprayed plants), amino acids at 300 ppm, silicon at 1 ml/L, seaweeds extract at 3 ml/L, amino acids + silicon, amino acids + seaweeds extract, silicon+ seaweeds extract, amino acids + silicon + seaweeds extract. The revealed results indicated that the use of compost at all levels led to a significant increase in plant growth traits (plant height, branch number / plant and herb dry weight/ plant) and also sepals dry yield/ plant and /fed., as well as % anthocyanin. In addition, all levels of compost significantly augmented acidity % except for the low one of compost (8 m³/ fed.) in the second season. The highest values of these traits were detected by applying the high level of compost (24 m³/ fed.). It could be noticed. That foliar spray with stimulant substances either single or together resulted a significant augment in these studied parameters, except for silicon treatment, mostly and, also amino acids treatment concerning acidity % in the second season. The application of the triple combined treatment (amino acids + silicon + seaweeds extract), followed, by the double combined one (amino acids + seaweeds extract) gave the highs values of plant growth characteristics. In connection, the highest values of sepals yield/ plant and fed., % acidity and anthocyanin % were given by foliar spray with the triple combined treatment (amino acids + silicon + seaweeds extract). The data showed that all studied traits were significantly affected by interaction treatments. Most combined treatments caused a significant increase in all examined parameters. In most cases, the addition of compost at the high level (24 m³/ fed.) with foliar spray with the triple combined treatment (amino acids + silicon + seaweeds extract), followed by the double combined one (amino acids + seaweeds extract).