Influence of Gibberellic acid and Methionine on growth, flowering quality, leaf anatomical structure and genetic diversity of Chrysanthemum morifolium Ramat plant

Ornamental plants are grown all over the world. In most countries, Chrysanthemum is considered one of the most popular cuts and potted flowers. Plants were sprayed with gibberellic acid (GA3) at concentrations (100, 200, and 300 ppm) and methionine (ME) at levels (200, 400, and 600 ppm), as bio-growth stimulants in the pre-blooming stage. The morphological and flowering parameters significantly increased by increasing the concentration of GA3. The highest values of K%, P%, total carbohydrates content, total phenols, total chlorophylls, and carotenoids in the leaf were obtained from gibberellic acid treatment at the rate of 300 ppm, while methionine at 600 ppm gave the highest value of protein in flowers. Also, various levels of gibberellic acid application significantly showed variation for days to initiation of Chrysanthemum flowers. The results of leaf anatomy showed an increase in most characteristics such as (thickness of the main vein, lamina, and spongy tissue) under study when spraying with gibberellic acid, especially at the concentration of 300 and methionine 600 ppm; respectively compared with control. Furthermore, inter-simple sequence repeat (ISSR) analysis has provided a powerful molecular marker for identifying variation with control and the best treatments. Therefore, the utilization of 300 ppm GA3 a plant growth regulator and 600 ppm ME an amino acid, these treatments are recommended to enhance Chrysanthemum parameters which lead to increasing its economic value as cut flowers and flowering potted plants as well as pharmaceuticals industries and multi-chemical uses. Keywords: Cut flowers; bio-growth stimulants; ISSR; leaf anatomy, growth regulators.