Some Effects of the Continuous Removal of Floral Buds on the Growth of the Cotton Plant

Plants of BP52Upland cotton which were continuously disbudded up to 23 weeks and 35 weeks after planting produced an average of 280 and 764 flower buds per plant respectively. Control plants produced only I I2 and I60 flower buds per plant over comparable periods. Disbudded plants produced significantly more flower buds on main-stem sympodia than did control plants; extensive development of monopodial branches with secondary sympodia also contributed to the increased number of buds produced by treated plants. Disbudded plants were taller than control plants at both 23 and 35 weeks. No increase in the dry weight of the aerial parts of control plants occurred between 23 and 35 weeks, although for disbudded plants there was an increase of 25 per cent, over this period. No major qualitative differences in amino-acid, organic acid, or sugar content were observed between treated and control plants at either stage. Between 23 and 35 weeks the absolute amounts of total nitrogen, soluble nitrogen, total sugars (excluding starch and cellulose), and reducing sugar held in stem and leaf material of control plants declined slightly, probably due to diversion of metabolites to developing bolls. Over the same period there was a slight increase in the amount of nitrogen and sugars held in the aerial parts of treated plants. These results are discussed with reference to the indeterminate fruiting habit of the cotton plant, and to the variable effects of disbudding on yield reported in the literature. The data support the classical theory of cotton plant nutrition in that there is evidence that maturation of bolls proceeds using nutrients which could otherwise be used for further growth and development of fruiting structure.