EFFECTS OF NITROGEN AND CHLORMEQUAT ON GROWTH AND GRAEV YIELD OF WINTER BARLEY CULTIVAR VALFAJR

A field experiment was conducted to investigate the effects of the growth regulator chlormequat (2-chloroethyl trimethyl ammonium chloride, CCC) and nitrogen as a top dressing fertilizer at three levels (0, 50 and 100 kg ha^-1) applied at the beginning of stem elongation, in addition to 18 kg N ha^-1 on seed bed, on growth and yield of winter barley (Hordeum vulgare L.). The results indicated that early application of CCC, i.e. application at glumme-lemma primordium stage of the main shoot, was associated with both increased fertile shoots per plant and grain number per spike and although the mean kernel weight of the CCC-treated plants was lower than controls, it was over-compensated for by increased grain number per plant, so that the grain yield was increased by CCC-treatment. Application of nitrogen also increased associated grain production and the grain yield at 50 and 100 kg N ha^-1 levels. The highest grain yield was obtained from plots which received early application of CCC with 50 kg N ha^-1. The interactive effect of CCC and nitrogen under the varying agroclimatic conditions of Iran is worthy of further exploration.