PRODUCTION OF SUNFLOWER (Helianthus annuus L.) AS A FLOWERING POT PLANT USING DIFFERENT POTTING MEDIA AND GROWTH RETARDANT TREATMENTS

Abstract

This study was carried out in the experimental nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, during the two successive years of 2007 and 2008. The aim of this study was to investigate the possibility of growing sunflower (Helianthus annuus L.) as a pot plant using different potting media and growth retardant treatments. The plants were grown in 25-cm pots filled with clay, clay+sand (1:1, v/v), clay+peat (1:1, v/v) or sand+peat (1:1, v/v), and were treated twice with paclobutrazol as a soil drench at 1.5, 3.0, 4.5 or 6.0 mg a.i./pot, or with Pix (mepiquat chloride) as a foliar spray at 500, 1000, 1500 or 2000 ppm, plus the control. The recorded results showed that using clay+peat (1:1, v/v) gave the best results for all the studied vegetative growth and flowering characteristics. In most cases, the different growth retardant treatments decreased plant height. The shortest plants were achieved with using paclobutrazol at 6 mg a.i./pot (in the first season) or Pix at 2000 ppm (in the second one). Growth retardant treatments (poclobutrazol or Pix) also decreased flower diameter, but increased the fresh and dry weights of flower-heads.