Modulation of Morphological Parameters in Onion (Allium cepa L.) through Plant Growth Regulators in the Subtropical Climate of Jammu

Abstract

The present study was initiated to assess the effect of plant growth regulators paclobutrazol and cycocel on morphological characters of onion (Allium cepa L.) under the subtropical agro-climatic conditions of Jammu. The field experiment was laid out at SKUAST-Jammu using two varieties of onion, N-53 and Agrifound Dark Red, in a randomized complete block design (RCBD) with three replications. Treatments consisted of foliar applications of PBZ @ 30, 60, and 90 ppm and CCC @ 50, 100, and 150 ppm plus untreated controls. It is evident from the results that the growth regulators induced significant modulation in most of the important vegetative and reproductive characters. Raising levels of PBZ and CCC caused a big decrease in plant height, neck width, scape length, and leaf count; the strongest blocking seen at higher amounts especially 90 ppm PBZ and 150 ppm CCC. Otherwise moderate levels like 60 ppm PBZ and 100 ppm CCC greatly improved flower parts such as number of flowers per umbel effective fruits and scape thickness showing better reproductive success. Varietal differences were obviously seen. Agrifound Dark Red showed best floral characteristics. N-53 showed best vegetative performance in non-treated and low-dose conditions. Justified use of PBZ and CCC mainly at moderate concentrations can be a strategic tool for regulation of plant architecture and reproductive success in onion cultivation within stress-prone subtropical environments.