Nitrogen and chlormequatchloride on cotton cultivar

Abstract

A field experiment was conducted in Tamil Nadu, India with cotton cv. MCU-5 during 1998-99 to determine the effect of N fertilizer rates and chlormequat chloride on growth, yield and quality of cotton. Treatments consisted of 3 N rates (60, 80 and 100 kg/ha) and 4 levels of chlormequat chloride formulations (50% AS, 30 ml/ha, 50% AS, 60 ml/ha, 10% AS, 150 ml/ha and 10% AS, 300 ml/ha). Chlormequat chloride spraying was done during the cotton flowering phase at 60, 70, 80 and 90 days after sowing. Cotton plant height was markedly increased with graded N rates and reduced to 17.6 to 33.6 cm in chlormequat chloride treatments. There was profuse vegetative growth of the test crop at 100 kg N/ha. When chlormequat chloride, either at low or high concentrations, were sprayed along with 100 kg N/ha, a profound height reduction leading to the development of short and sturdy plant was observed. In terms of the yield attributes, chlormequat chloride sprayed in two formulations (50% AS, 30 ml/ha x 4 applications at 60, 70, 80 and 90 days interval and 10% AS, 150 ml/ha x 4 applications at 60, 70, 80 and 90 days interval) and with increased N rates produced more monopodia, sympodia and bolls compared to the control that did not receive chlormequat chloride. The boll weight was also profoundly increased. The favourable influence of chlormequat chloride alone at lower concentration and with N on yield contributing factors resulted in marked increase in the yield of seed cotton. However, the quality parameters remained unaffected due to the chlormequat chloride spraying.