Effect of detopping and mepiquat chloride application in soybean (Glycine max)

Investigation was carried out in Punjab Agricultural University, Ludhiana, during kharif 2014 and 2015 to evaluate the effect of detopping and mepiquat chloride (MC) application on economics and seed quality of soybean (Glycine max L.) cv. SL 744. The experiment was laid-out in randomized complete block design having eight treatments as T1-control, T2-detopping (removal of 4–5 cm apical portion of main stem) at 50–55 days after sowing (DAS), T3-MC @ 200 ppm at 50–55 DAS, T4-MC @ 200 ppm at 50–55 and 65–70 DAS, T5-MC 250 ppm at 50–55 DAS, T6-MC @ 250 ppm at 50–55 and 65–70 DAS, T7-MC @ 300 ppm at 50–55 DAS and T8-MC @ 300 ppm at 50–55 and 65–70 DAS, with four replications. An increase in seed nitrogen and protein content with increase in level of MC was recorded but it could not reach the level of significance. Anon-significant effect of detopping and MC application on stover nitrogen and seed oil content was also recorded. A non-significant effect of growth regulation treatments on seed quality parameters viz., germination percentage, seedling length and dry weight, vigour index I & II and speed of germination index was recorded which indicates non-inhibitory effect of MC on seed quality of soybean. Detopping and application of MC @ 250 ppm at two growth stages resulted in highest gross and net returns and benefit to cost ratio (B: C) in comparison to control indicating economical viability of detopping and MC application.