~ 2220 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(2): 2220-2223 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(2): 2220-2223 Received: 07-01-2018 Accepted: 08-02-2018 Desh Raj Choudhary (a) Department of Vegetable Science, CCS HAU, Hisar Haryana, India (b) Division of Vegetable Science and Floriculture, SKUAST, Jammu, Jammu & Kashmir, India Satesh Kumar Division of Vegetable Science and Floriculture, SKUAST, Jammu, Jammu & Kashmir, India Correspondence Desh Raj Choudhary (a) Department of Vegetable Science, CCS HAU, Hisar Haryana, India (b) Division of Vegetable Science and Floriculture, SKUAST, Jammu, Jammu & Kashmir, India Economics and yield response of onion to plant hormones and age of seedling Desh Raj Choudhary and Satesh Kumar Abstract The response of three seedling age (6, 8 and 10 week old seedling) of onion cultivar N-53 was studied against different plant hormonal treatments viz., cycocel (500 & 1000ppm), ethephon (2000 & 2500ppm) and paclobutrazol (1000 & 2000ppm) in factorial RBD replicated thrice during Rabi season of 2014- 2015. The results showed that 8 week old seedlings outperformed other aged seedlings with highest yield, quality, plant establishment and economics. Data with respect to yield attributes clearly pointed out that 8 week old seedlings performed better and showed statistically higher bulb yield (9.54kg/plot), total bulb yield (212.06q/ha) and marketable yield (205.40q/ha) over the 10 and 6 week old seedling. All plant hormones significantly reduced vegetative growth as compared to control. Amongst them, paclobutrazol @ 2000ppm was found statistically superior in terms of per plot bulb yield (8.57 kg/plot), total bulb yield (190.78q/ha), marketable yield (181.83q/ha) and minimum unmarketable bulb yield of (8.53 q/ha) as compared to other treatments. Interactive effect of paclobutrazol @ 2000ppm sprayed on 8 week old seedlings (A2P2) produced significantly higher marketable yield (279.50q/ha). Economics of the experiment showed maximum B: C ratio in 8 week old seedling with 2000 ppm paclobutrazol (4.4) with higher net returns of (₹ 3, 46,869) as compared to other treatment as well as control. Keywords: B:C ratio, economics, net return, plant hormones, seedling age, yield Introduction Onion (Allium cepa L.) is one of the important bulb crops belonging to family Alliaceae and has gained the importance of a cash crop in recent years. India is the second largest producer of onion in the world after China. During 2013-14, onion occupied 12.03 lakh hectares with production of 19.40 lakh MT in India after China and third in export (18.22 lakh MT) after Netherlands and Spain, with foreign exchange earnings of 1966.6 crores (Anonymous, 2014). The major onion growing states are Maharashtra, Bihar, Karnataka, Gujarat, Andhra Pradesh, Uttar Pradesh, Odisha, Madhya Pradesh, Rajasthan and Haryana. Onion is characterized by its distinctive flavour and pungency, which is the due to sulphur containing compounds Allylpropyl-disulphide, found in the scales of the bulb. The cultivation of onion is highly technical and depends on environmental conditions such as photoperiod and temperature as well as growth rate and number of days to maturity (Steer, 1980). The factors like seedling age at the time of transplanting, hormonal imbalance of the plant, etc. affect the yield of onion. Plant hormones have an interesting role particularly in modern agriculture (Ashraf et al., 2010) [3] to improve and accelerate plant physiology. The knowledge of their metabolic and transport pathways will lead to new opportunities to manipulate plant growth. However, their use in crop like onion was not realized on commercial basis. Relatively slow growth and early cessation of cell elongation are the characteristics that can be directly linked to scape formation. Their role as anti-gibberellins could be utilized in various growth processes in onion such as bulbing and senescence (Levy et al., 1972) [7] . Keeping in view the present investigation has been undertaken to determine the relationship of seedling age and exogenous application of plant growth regulator on economics and yield of onion. Material and Methods The present study was carried out at Vegetable Research Farm, Division of Vegetable Science and Floriculture, SKUAST, Chatha, Jammu (J&K) situated at 33 0 55' N latitude and 74 0 58' East longitude with altitude of 296 meter above mean sea level during Rabi season of 2014- 2015. The experiment was laid out in a factorial randomized block design (RBD) with three replications comprising of three seedling age (6, 8 and 10 week old) and seven plant hormonal treatments viz., cycocel 500ppm (C 1 ), cycocel 1000ppm (C 2 ), ethephon 2000ppm (E 1 ), ethephon 2500ppm (E 2 ), paclobutrazol 1000ppm (P 1 ), paclobutrazol 2000ppm (P 2 ) and