Jhanji, ShaliniGurpreet Kaur2022-08-282022-08-282021Gurpreet Kaur (2021). Effect of post harvest foliar spray of plant growth regulators on flower quality of chrysanthemum (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810186786The present investigation entitled “Effect of post harvest foliar spray of plant growth regulators on flower quality of chrysanthemum” was undertaken in the Department of Floriculture and Landscaping and the Department of Botany of Punjab Agricultural University, Ludhiana during the year 2020. The stems of chrysanthemum cv. White Star (spray type) were harvested when ¾ th outer florets were fully expanded. The stems were treated with different chemical solutions of plant growth regulators (PGRs)- Benzyl adenine (50, 100, 150 and 200µM), Thidiazuron (5, 10, 15 and 20µM) and Salicylic acid (50, 100, 150 and 200µM) through pulsing (for 24 h) and postharvest foliar spray application. One set of stems were similarly treated with water representing control. The stems treated with water (control) exhibited early senescence of florets (16.84 days) and yellowing of leaves (11.65 days) which was associated with decline in membrane stability index, chlorophyll content, total soluble sugars, total soluble proteins, activity of antioxidant enzymes viz. peroxidase (POX) and catalase (CAT). Treatments with plant growth regulators prolonged post harvest longevity of florets as well as leaves as compared to control. This effect was associated with increase in the activities of antioxidant enzymes, maintenance of total soluble sugars and proteins, improved water uptake by the stems. The morpho-physiological and biochemical attributes were found to be high at initiation of vase life and gradually decreased with progression of time till end of vase life in all the treatments. Cluster analysis inferred that pulsing solutions of BA@50 and100µM and TDZ@5 and10µM were found to be efficient in delaying floret senescence (24.01 days) and leaf yellowing (20.54 days) in cut chrysanthemum stems. Pulsing was considered to be effective than foliar spraying as a means of applying PGRs. TDZ@5µM gave the best results in terms of improving the postharvest life of chrysanthemum stems among the various PGRs.EnglishThesis