Effect of different phosphorus levels on earliness and yield of cotton cultivars

To determine the effect of phosphorus levels on earliness and yield of cotton, three cultivars viz., CIM-496, MNH-786 and FH-901 were grown in field with four phosphorus levels (0, 30, 60 and 90 kg ha^-1) following a 3 x 4 factorial arrangement during the year 2008. Cultivars as well as phosphorus levels significantly affected almost all the characters related to earliness and yield. Among the cultivars, FH-901 took minimum days for squaring, appearance of first flower, first boll splition and for boll maturation period. The same variety recorded the lowest node number for first fruiting branch, lowest fruiting branch height and maximum earliness index. Among the phosphorus levels, control took the maximum while 90 kg ha^-1 took minimum days for all earliness related characters. Earliness index (53.5 %) and seed cotton yield (1879.5 kg ha^-1) were highest with 90 kg P ha^-1. Production rate index remained unaffected by variety; however it was highest where no phosphorus was added. So, maximum seed cotton yield and earliness in cotton can be achieved by growing a short duration cultivar with higher dose of phosphorus.