Effect of paclobutrazol on growth and seed yield of cosmos (Cosmos bipinnatus L.) Kumar Yogendra1, Tsomu Thupten1,*, Sisodia Anjana1, Sahu Tijeshwari1, Kumari Priyanka1 1Department of Horticulture, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221 005 (Uttar Pradesh), India *Thupten Tsomu (Corresponding author) thupten.tsomu@bhu.ac.in
Online Published on 18 March, 2023. Abstract Field experiment was carried out at Experimental Farm of the Department of Horticulture, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi (Uttar Pradesh) during 2021-22 to analyse the effect of soil drenching with paclobutrazol (PBZ) on cosmos (Cosmos bipinnatus L.). Treatments consisted of eight dosages of paclobutrazol (1.25, 2.75, 3.75, 5.00, 6.25, 7.50, 8.75 and 10.00 mg L-1) and control (0 mg L-1) were used. The experiment was laid out in randomized block design with nine treatments and four replications. Significant results were obtained in various growth and seed yielding parameters of cosmos after drenching with paclobutrazol. Positive effect of paclobutrazol was observed when it is applied at the rate of 1.25 mg L-1 (T2) as it resulted in maximum number of primary branches per plant (15.02) at 60 days after transplanting (DAT) and 90 DAT (22.04) as well as maximum number of secondary branches per plant at 60 DAT (24.49) and 90 DAT (99.25). PBZ 1.25 mg L-1 treatment (T2) was also observed to give maximum plant spread at 60 DAT (47.42 cm) and 90 DAT (75.33 cm) as well as maximum number of leaves per plant (481.34). Drenching with PBZ 10.00 mg L-1 resulted in maximum reduction of plant height at 60 days (36.50 cm) and 90 days (65.51 cm). There was a decreasing trend in plant height with increasing dosage of paclobutrazol. In terms of various seed parameters, PBZ 1.25 mg L-1 treatment (T2) again resulted in beneficial effect with production maximum number of seed per flower (63.60), maximum seed yield per plant (60.68 g) and maximum seed yield per meter square (199.83 g), while maximum test weight (9.08 g) was recorded from plants treated with treatment T6i.e. PBZ 6.25 mg L-1. Treatment with paclobutrazol resulted in delayed seed ripening as maximum days (99.83 days) was recorded in treatment T4i.e. PBZ 3.75 mg L-1. Top Keywords Cosmos, Drenching, Growth attributes, Paclobutrazol, Yield, Yield attributes. Top |