~ 1831 ~ International Journal of Chemical Studies 2020; 8(4): 1831-1835 P-ISSN: 2349–8528 E-ISSN: 2321–4902 www.chemijournal.com IJCS 2020; 8(4): 1831-1835 © 2020 IJCS Received: 07-05-2020 Accepted: 09-06-2020 Ganpat Lal Yadav Department of Horticulture, S.K.N. College of Agriculture, Jobner SKNAU, Jobner, Rajasthan, India SP Singh Department of Horticulture, S.K.N. College of Agriculture, Jobner SKNAU, Jobner, Rajasthan, India Mahendra Yadav Department of Horticulture, S.K.N. College of Agriculture, Jobner SKNAU, Jobner, Rajasthan, India Corresponding Author: Ganpat Lal Yadav Department of Horticulture, S.K.N. College of Agriculture, Jobner SKNAU, Jobner, Rajasthan, India Effect of bio-fertilizers and bio-regulators on yield and net returns of garlic ( Allium sativum L.) Ganpat Lal Yadav, SP Singh and Mahendra Yadav DOI: https://doi.org/10.22271/chemi.2020.v8.i4s.9893 Abstract A field experiment was conducted at Horticulture Farm, S.K.N. College of Agriculture, Jobner (Jaipur) during Rabi season 2016-17 and 2017-2018. The experiment consisted four bio-fertilizers (Azotobacter, PGPR (Pseudomonas) and Azotobacter + PGPR (Pseudomonas) and five bio-regulators (Thiourea @ 500ppm, Thiourea @ 1000ppm, salicylic acid @ 100 ppm and mepiquat chloride @ 100 ppm). The total 20 treatment combinations were tested in split-plot design with three replications. Further, it can be concluded that combined application of Azotobacter + PGPR (Pseudomonas) along with thiourea @ 1000 ppm proved to be most superior treatment combination as it fetched comparable bulb yield (223.58 q/ha), net returns ( 1,89,332 /ha) and B: C ratio (2.40) followed by Azotobacter + PGPR (Pseudomonas) along with thiourea @ 500 ppm and Azotobacter + PGPR (Pseudomonas) along with salicylic acid @ 100 ppm. Keywords: Azotobacter, PGPR (Pseudomonas), thiourea, salicylic acid and mepiquat chloride Introduction Garlic is the second important bulb crop after onion. Botanically it is known as Allium sativum which belongs to the family Amaryllidaceae. It is a multiple or compound bulb consists of smaller bulblets called ‘cloves’ and is surrounded by a thin white or pinkish papery sheath. The economic yield is obtained from these cloves. As bio-fertilizers are the recent sources for fixation of atmospheric nitrogen in to the soil and making it readily available for the growth of plants. Among the bio-fertilizers, Azotobacter though having limited use in vegetables, yet has established its bio-activity in cereals, oilseeds and other crops for mobilizing the useful macro nutrients from unusable to usable state and increase the crop production by enhancing soil fertility. In addition, the bio-fertilizers not only supplement the nutrition but also improve the efficiency of applied nutrients (Somani et al., 1990) [18] . Further, Pseudomonas fluorescensis common non-pathogenic saprophyte that colonizes in soil, water and on plant surfaces. It produces a soluble greenish fluorescent pigment. It suppress plant diseases by protecting the seeds and roots from fungal infections by production the number of secondary metabolites including antibiotics, siderophores and hydrogen cyanide. This microbe has the unique ability to enter the plant vascular system and reach to the various parts of the plant system and act as a systemic bio-control agent against various fungal and bacterial diseases. It is applied as Seed treatment @ 4-5 g per kg of seeds as per standard wet treatment (Yawalkar et al., 1996) [22] . Furthermore, thiourea plays a vital role in the physiology of plants both as a sulfhydryl compound and to some extent as an amino compound like urea. The stimulating action of thiourea in various physiological activities of plant is well known. Thiourea is mainly known for its dormancy breaking and germination stimulating effect (Mayer, 1956; Mayer and Poljak off-Mayber, 1958) [10, 11] . The dormancy breaking effect of thiourea was suggested to be related to its growth enhancing effect. Similarly salicylic acid is one of the important bio-regulator which positively affects growth of plants. It is classified as phenolic growth regulator, a non- enzymatic antioxidant, a signaling or messenger molecule in plants to induce responses of plants to environmental stressors. SA plays an important role in the regulation and development of ion uptake, transport and membrane permeability (Simaei et al., 2012) [16] . Salicylic acid (SA) or ortho-hydroxy benzoic acid is a common plant-produced phenolic compound. Which contributes in the regulation of physiological, biochemical and molecular processes and therefore, it affects the plant growth, development and productivity (Hayat et al., 2010) [9] .