EFFECT OF GROWTH RETARDANTS AND NIPPING ON GROWTH PARAMETERS AND YIELD IN COWPEA (VIGNA UNGUICULATA L.)

A field experiment was conducted during Kharif season of 2004-05 to study the effect of growth retardants and nipping on productivity of cowpea var. C-152 in relation to physiological parameters like AGR, RGR, CGR, NAR, LAI, LAD, LAR and harvest index. Nipping at different times and different concentrations of growth retardants were imposed after 35 days after-sowing (DAS). At 90 DAS significantly more LAI was observed in nipping at tendril formation followed by nipping at two weeks after tendril formation and lihocin (500 ppm). The AGR differed significantly at 60-90 DAS. It was highest in mepiquat chloride (1000 ppm) followed by mepiquat chloride (500 ppm). In all the treatments CGR increased over control and was highest in mepiquat chloride (1000 ppm). Although mepiquat chloride (1000 ppm) recorded highest yield, mepiquat chloride (500 ppm) and nipping at one week after tendril formation were found to be more economical.