The book “Plant Growth Regulators, Biostimulants and Chemicals on Horticultural Crops” is aimed to address the recent development in both basic and applied aspects of plant growth regulators on horticultural crops. Over the last 60 years, plant growth regulators (PGRs) become an integral part in the production of crops in general and horticultural crops in particular. Moreover, the importance of PGRs is felt more immensely in horticultural crops than the field crops. The perennial nature, rich in phytochemicals, shelf-life and other quality attributes of horticultural crops warrants the physiological interventions through applications of PGRs. Hence, this book has been designed to address the above issues and also to fulfill the needs of the undergraduate, post-graduate students of horticulture in the field of PGRs across the country. This book comprises of both basic (seven chapters) and applied aspects (14 chapters) of plant growth regulators including plant growth inhibitors and retardants and novel plant growth regulators. The other basic aspects are animal products as bioenhancer, plant extracts, growth regulating biochemicals and other inorganic chemicals used to stimulate the crop growth. The role of PGRs in enhancing plant growth, yield, quality and shelf-life of different horticultural crops viz., fruits, vegetables, spices, plantation crops, medicinal, aromatic, flowers and ornamental plants are included in the applied aspects. In addition to the above, preparations of PGRs solutions, PGRs use efficiency, phytotoxicity and other guidelines and safety measures are also included as chapters. It can be humbly claimed that such exclusive and elaborative collection and compilation of recent developments in the field of PGRs and its applications in horticultural crops in a single publication of its kind and this publication will be useful to the students, teachers, scientists, planners and farmers concerned with production of horticultural crops Contents: Part-I: Principles of Plant Growth Regulators 1. Plant Growth Regulators, A. Classical Plant Growth Regulators, B. Growth Inhibitors and Retardants, C. Novel Plant Growth Regulators, 2. Animal Products as Bioenhancer, 3. Plant Extracts as Growth Stimulants, 4. Plant Biostimulants, 5. Growth Regulating Biochemicals, 6. Growth Regulating Synthetic Chemicals, 7. Growth Stimulating Inorganic Chemicals, Part-II: Practical Applications of Plant Growth Regulators in Horticultural Crops 8. Fruit Crops, 9. Vegetable Crops, 10. Spices, 11. Plantation Crops Medicinal Plants, 13. Aromatic Plants, 14. Flower Crops, 15. Ornamental Plants, 16. Plant Growth Regulators in Tissue Culture, 17. Preparation of Plant Growth Regulator Solutions, 18. Methods of Plant Growth Regulators Application, 19. Plant Growth Regulators Use Efficiency, 20. Phytotoxicity of Plant Growth Regulators ................................577 21. Guidelines, Precautions and Safety Measures, References . About the Author: About Author Content Dr. J. Rajangam, started his career as an Assistant Professor of Horticulture during 1995 at Tamil Nadu Agricultural University (TNAU), Coimbatore. As a Horticulturist, he has more than 26 years experience in various horticultural crops. During his career, significant contributions were made pertaining to release of varieties CO3 in Chillies, PKM 2 in Annual moringa, PKM 1 in Davana, PKM 2 in Manilla tamarind and PKM 1 in Wood apple. He served as a Professor and Head, Horticultural Research Station, Kodaikanal for a period of four years. During his tenure, he was officer-in-charge of All India Network Project on Temperate Fruit Crops at Horticultural Research Station, Kodaikanal with CITH, Srinagar and Principal Investigator of ICAR-AICRP (Fruits) at Horticultural College & Research Institute, Periyakulam. He offered UG and PG courses for more than 20 years and guided 16 M.Sc. (Hort.) and 2 Ph.D. students. He has published more than 30 papers in National and International research journals, 112 popular articles, 15 booklets and three books. He visited Israel and Tanzania for Post Graduate Certificate Programme in Protected Horticulture and International Symposium on Moringa cultivation and utilization. He served as a scientist incharge of genetic resource conservation and documented 240 mango, guava and underutilized fruits genotypes as per NBPGR, New Delhi guidelines. He developed technologies for Ultra High Density Planting System in mango and guava. For his contribution for canopy development in fruit crops, he was awarded Mahindra Samriddhi National Award for the year 2019-2020. Currently, he is serving as the Professor and Head, Department of Fruits Science, Horticultural College and Research Institute, Periyakulam (TNAU, Coimbatore). Dr. A. Subbiah is presently working as an Assistant Professor and Head at Grapes Research Station, (TNAU), Theni, Tamil Nadu. He was the recipient of ICAR Junior Research Fellowship for his Master Degree during 1997 and completed his Ph.D., in 2004 from Tamil Nadu Agricultural University, Coimbatore. He worked as a Research Assistant at Cardamom Research Station, Pampadumpara, Idukki, Kerala (KAU), Senior Research Fellow at Department of Vegetable Crops, TNAU, Coimbatore and Technical Executive of Indian Spices Producers Company, Cochin, Kerala. He is involved in teaching courses on fundamentals of horticulture, production and post-harvest technology of fruits to the Under v Graduate students in Horticulture for the past 10 years. He also served as Co-Principal Investigator in the ICAR-NICRA Research Project on “Studies on Mango Flowering Phenology” and IDRCCIFSF, Canada funded Project on “Enhanced Preservation of Fruits in Asia by using Nano Film Techniques”. Further, he is also in-charge of Venture Capital Scheme ‘’Mass multiplication of grape rootstocks and varieties”. He is associated with 10 various scientific societies involved in promotion of research and development in fruits, spices and plantation crops as time life member. He has also served as a member of Board of Studies for UG Programme in Horticulture, Tamil Nadu Agricultural University during 2010-2013. He has authored and co-authored 4 book chapters and 8 books and published 23 research papers in reputed National and International Journals. He organized various training programmes on production technology of grapes to the farmers. Dr. C. Rajamanickam is presently working as Associate Professor and Head, Citrus Research Station (TNAU) Vannikonenthal, Sankarankovil, Tirunelveli District, Tamil Nadu. He obtained his B.Sc. (Horticulture) and M.Sc. (Horticulture) from Horticultural College and Research Institute, Periyakulam, a constituent college of Tamil Nadu Agricultural University, Coimbatore and Ph.D. (Horticulture) from College of Agriculture, Kerala Agricultural University, Vellayani, Thiruvananthapuram, Kerala. He is having 15 years of experience in teaching, research and extension. During the year 2017-2018, he served as Programme Coordinator, ICAR-Krishi Vigyan Kendra, Ramanathapuram and conducted many training programmes on cultivation of fruits, vegetables, flowers and plantation crops. He offered more than 30 courses in horticulture to both B.Sc. (Hort.) and B.Sc. (Ag.) students and three courses to M.Sc. (Hort.) students. He guided two M.Sc. (Hort.) students and played active role as member of advisory committee for more than 20 post-graduate students in different disciplines of Agriculture. He is expertise in propagation of fruit crops and also in nursery management. He solved many field problems in horticultural crops. He has authored one book, published more than 27 research papers in both National and International Journals, 6 books in regional language, 35 book chapters and several booklets during his career. He has participated more than 20 National and International seminar, conference, symposia and workshops. He is a member of six elite professional scientific societies across the country. He is the Principal Investigator of NICRA scheme for two years and handled two externally funded projects as Co-Principal Investigator. He has received one best researcher award by Malarum Velanmai Journal, Coimbatore during the year 2015. Dr. K.S. Vijai Selvaraj has completed his undergraduation in B.Sc. (Horticulture) at Horticultural College and Research Institute, TNAU, Periyakulam during 1998-2002 and pursued Masters degree M.Sc., (Horticulture) at Agricultural College and Research Institute, TNAU, Madurai during 2002-2004. He completed his Ph.D. in Horticulture during 2004-2007 at Horticultural College and Research Institute, TNAU, Coimbatore in collaboration with The Hebrew University of Jerusalem, Israel. Also, he completed his Post Doctoral Research in Agriculture Research Organization, The Volcani Centre, Israel during 2008- 2009 in Molecular Physiology and Genetic Engineering. Currently, he is working as an Assistant Professor of Horticulture at Agricultural College and Research Institute (TNAU), Eachangkottai, Thanjavur district, Tamil Nadu and handled 8 Undergraduate courses and operating 2 externally funded projects. He has published 12 international research papers, 5 national research papers, 3 books with ISBN and 10 popular articles. Dr. P. Balasubramanian is presently working as an Assistant Professor of Horticulture, ICAR-Krishi Vigyan Kendra (TNAU), Ramanathapuram District, Tamil Nadu. As a horticulturist, he has more than 11 years of research experience in various horticultural crops. He served as Programme Coordinator of ICAR-KVK at Ramanathapuram district. He has been recognised as ASCI certified trainer for coconut growers. He is the Principal Investigator of NICRA scheme (RS. 11.0 lakhs), DAMU (6.00 lakhs) and ASCI (3.5 lakhs) at KVK, Ramanathapuram District. During his career, significant contributions were made pertaining to the release of variety MDU-1 in cluster bean. He served as a Farm Manager at Soil and Water Management Research Institute, Thanjavur and also at the Department of Horticulture, Agricultural College and Research Institute, Madurai for a period of seven years. He is the Principal Investigator of BRNS - GOI, Mumbai scheme entitled “Isolation of short statured early maturing mutant in cluster bean through gamma irradiation” with a budget of Rs. 24.11 Lakhs. He offered courses in horticulture for more than seven years for U.G, P.G, Ph.D. students in Horticulture and also guided two M.Sc. (Hort.) students. He has published 2 books and 13 research articles in peer reviewed National and International journals. Dr. T. Sivakumar obtained his B.Sc. (Ag) from Agricultural College and Research Institute (TNAU), Killikulam, Tuticorin District of Tamil Nadu and M.Sc. (Plant Physiology), Ph.D. (Plant Physiology) from ICAR-IARI, New Delhi. At present, he is working as a Professor of Crop Physiology, Agricultural College & Research Institute, Madurai, Tamil Nadu, India. He joined the Tamil Nadu Agricultural University in 2004 and served seventeen years in various capacities in teaching, research and extension. He has been the recipient of coveted fellowships and invitee to deliver lectures on specialized topics in premier institutions across the country. He is currently working on source - sink relationship, seed physiology and postharvest physiology. He has published a number of research papers in both National and International journal. He is a member of the elite professional scientific societies like Indian Science Congress Association, Indian Society for Plant Physiology, etc. He has attended many symposia, conferences and seminars at both National and International level. Dr. K. Balakrishnan, started his career as an Assistant Professor of Crop Physiology at Horticultural College and Research Institute, Coimbatore in the year 1985. He was the recipient of ICAR Senior Fellowship during 1983 and obtained Ph.D. in Crop Physiology in 1987 from Tamil Nadu Agricultural University, Coimbatore (TNAU). He has also obtained Post Graduate Diploma in Journalism in 1988. He has also worked as a Technical Assistant in United Planter’s Association of South India, Coonoor, Nilgiris, Tamil Nadu during 1981-1983. He has been teaching courses on Crop Physiology and Biochemistry to the Undergraduate and Post Graduate students in both Agriculture and Horticulture for the past 32 years. He served as a Principal Investigator of Foliar diagnosis in Horticultural Crops in plan scheme funded by Government of Tamil Nadu, Post Harvest Technology of Horticultural Crops ICAR-PHT at Horticultural College and Research Institute, Periyakulam and Arid zone fruit crops, funded by AICRIP (ICAR), at Regional Agricultural Research Station (TNAU), Aruppukottai. He operated several schemes from both private and Government agencies. He was the member of All India ICAR Syllabus Committee on basic Agricultural, sciences during 2007-2008. He has also served as a member of Board of Studies in Agriculture, Tamil Nadu Agricultural University during 1997-2000. His expertise in foliar diagnosis of nutritional disorders in crop plants is well-recognized by invitation to deliver lectures on various aspects of diagnosis of nutritional and physiological disorders in NGOs, Extension officials and farmers organisations. He has solved many physiological field problems. He was the founder inchage of Venture Capital Scheme on “Production of Coconut Tonic” at AC&RI, Madurai since 2006. He has authored and co-authored 15 book chapters and 9 books and published 60 research papers in both National and International journals, 3 extension bulletins and 120 popular articles. He has been the question setter and external examiner for M.Sc. (Ag.) and Ph.D. students in several State Agricultural Universities. He has organized one National Seminar at AC & RI, Madurai during September 2013. He has served as the Professor and Head, Department of Seed Science and Technology, Agricultural College and Research Institute, Madurai during 2013-2015. Recognition of his 25 years of meritorious service, TNAU awarded in best scientist award on 41st Foundation Day celebration held on June 01, 2011. He was awarded with Thiruvalluvar Award for his contribution in Teaching Crop Physiology courses to the undergraduate students in Agriculture by Alumni Association of Agricultural College and Research Institute, Killikulam in 2017. He has been awarded Fellow of Bose Science Society (FBSS) by the Tamil Nadu Scientific Research Organization, Tamil Nadu during January 2018 for his commendable achievement in the field of Crop Physiology.