EFFECT OF SOME GROWTH RETARDANTS ON GROWTH AND FLOWERING OF HELIANTHUS ANNUUS L. CV. SUNRICH ORANGE SUMMER 981V PLANTS B- APPLICATION OF ANCYMIDOL, DAMINOZIDE AND ETHEPHON IN COMBINATIONS

Pot experiments were carried out at the nursery of Hort. Res. Inst, Giza, Egypt throughout the two successive seasons of 2014 and 2015. The work embodied in this paper was to study the influence of some growth regulators (daminozide, ancymidol and ethephon) on sunflower (Helianthus annuus L. cv. Sunrich Orange Summer 981V) plant for achieving the hope of producing dwarf plant of good quality.
The objective of this investigation was to detect the response of sunflower plants to tank mix ratios and application methods of ancymidol, daminozide and ethephon for production of a dwarfed and picturesque specimen in an appropriate size. The results indicated that all the used combinations significantly decreased stem length of the treated plants. The shortest stems and internodes were obtained by ancymidol at either 5 or 20 ppm (seed soaking) + 500 ppm ethephon (spray). Stem diameter was increased by all combinations to reach the maximum by 5 ppm ancymidol (spray) + 500 ppm ethephon (spray). The number of internode/stem was not greatly affected by the used combinations. However, the number of leaves/plant was significantly increased by all treatments. Also, all combinations caused a marked increment in the root length, with the superiority of 20 ppm ancymidol (seed soaking) + 2450 ppm daminozide (spray), which scored the longest roots in the two seasons. Spraying plants with 5 ppm ancymidol + 250 ppm ethephon or 20 ppm ancymidol + 500 ppm ethephons induced the greatest precocity in flower bud appearance and opening. Seed soaking in 20 ppm ancymidol solution and spraying with 1250 ppm daminozide reduced number of days from flower bud appearance to its opening . The mean number of lateral buds/stem, number of ray flowers/head and disc diameter were significantly improved, with few exceptions due to the different combinations than control plants in both seasons. Data, revealed that the highest content of chlorophyll a, b, carotenoids and total phenols were scored by spraying with either 5 or 20 ppm ancymidol + 500 ppm ethephon solutions. Total indoles and total soluble sugars were inconsistent and the percent of N was generally decreased. As for P%, it increased by most combinations, but K% increased only by combining between ancymidol + ethephon.