Propagation of Croton Cuttings Relation to Hormones and Seasonal Changes

Eight experiments were carried out at Antoniades Research Branch, Ornamental Plants Research and Landscape Gardening Department Horticulture Research Institute, A.R.C., Alexandria, Egypt during the eight successive seasons, i.e. winter, spring, summer and fall during 2019 and 2020 to investigate the effect of indole butyric acid and seasonal changes on stem cuttings and rooting growth of Croton plants (Codiaeum variegatum L.). The cuttings were treated with four different concentrations of IBA at the rate of 1000, 2000, 3000 and 4000 ppm besides the control. Both 2000 and 3000 ppm IBA significantly improved rooting percentage%, survival % of cuttings and produced a significant increase in all vegetative root growth parameters (number of roots, fresh and dry weight of roots and root length).  In addition, treated cuttings with 2000ppm also decreased the number of days to root. After 45 days, the rooting percentage gradually increased in comparison to the increase in IBA concentration to over 2000ppm, with results exceeding 88 percent in February. Furthermore, low-efficiency doses of growth regulators have led to fewer roots per cutting, potentially jeopardising the cuttings' survival under greenhouse conditions. In contrast, the greater temperature beneath the greenhouse and endogenous -auxin in the cuttings may be responsible for the rise in rooting percentage and improvement in root system metrics seen in the winter and spring after the autumn.