Neog, ManoranjanBagra, Gerik2024-07-112024-07-112023https://krishikosh.egranth.ac.in/handle/1/5810211810An experiment was conducted on “Floral behaviour, growth and postharvest quality of dragon fruit [Hylocereus costaricensis (Weber) Britton & Rose] during 2019-20 and 2020-21 in the farm of KVK, Jorhat and Laboratory, Department of Horticulture, Assam Agricultural University, Jorhat with the objectives to study the floral behaviour, growth and development of dragon fruit and also the effect of various post-harvest treatments on its post-harvest quality and shelf life. The plants were tagged at bud initiation stage. The floral behaviour of the fruits was studied in the selected plants. The fruits were collected at 7 day intervals after flowering, till harvest for estimation of various physico-chemical parameters. Six post-harvest treatments; T1(Dipping fruits in ascorbic acid 500ppm solution for 5 minutes, air dried and packed in transparent 0.2% perforated LDPE bags), T2(Dipping fruits in 100 ppm sodium hypochlorite for 5 minutes, air dried and packed in transparent 0.2% perforated LDPE bags), T3(Dipping fruits in 1% Chitosan solution for 2 minutes, air dried and packed in transparent 0.2% perforated LDPE bags), T4(Dipping fruits in 1% Calcium Chloride solution for 30 minutes, air dried and packed in transparent 0.2% perforated LDPE bags), T5(Air dried fruits packed in transparent 0.2% perforated LDPE bags),T6(Air dried fruits were kept in open condition without packing and chemical treatment) were applied to fruits. Fruits were subjected to post harvest treatments after harvest and kept at ambient conditions (mean temp 30.5 0C and RH 82.5%). Physicochemical qualities were studied at 2 days, 4 days, 6 days and 8 days after storage (DAS). The laboratory experiment (Part II) was laid out in a factorial CRD with three replications. The flower bud initiation started in the second week of July and it took 18 days to flower. Anthesis started in the afternoon and the period lasted from 4.30 to 9.00 pm. The dehiscence of anthers took place 7 hours after opening of flowers. Pollen viability percentages were found to be 85.77±0.89 and 84.62±0.20 under 10x and 40x magnification, respectively. Fruits reached harvest maturity at 28 days after flowering when peel colour changed to pink red. At harvest, it recorded fruit weight 239.92 g, specific gravity 1.05, pulp:peel ratio 2.59 and the fruit contained TSS 11.95 0Brix, titrable acidity 0.26%, TSS:acid ratio 48.20, total sugar 8.12 %, crude protein 1.19 %, Crude fibre 0.84 mg/g, Total phenolics 51.94 mg GAE/g, Betalains 8.60 mg/100g. Physiological loss in fruit weight (PLW) were increased during storage. T2 recorded the lowest PLW (1.66%) and absence of rotting of fruits which was followed by T1. In T2 and T1, no fungal organism was detected. TSS and sugars were found to increase during storage while titrable acidity and ascorbic acid content decreased. T2 registered the lowest titrable acidity (0.16%) which was followed by T1 & T3 (0.18 %). Highest TSS (12.21 OBrix) and total sugars (8.30%) were recorded in T1 which had statistical parity with T2. Maximum retention of ascorbic acid (8.04%), Crude protein (0.72%), total phenolics (49.28mg GAE/100g), crude fibre (1.03%), Betalain (8.54mg/100g), total antioxidant (53.14 mg/g) were recorded in T2 which was followed by T1. Organoleptic qualities of fruits were found to decrease with the advancement of storage period. The highest organoleptic score values in respect of colour (7.89), taste (7.678), flavour (7.19) and texture (7.20) were obtained in T2 followed byT1. Maximum shelf life of 8 days was recorded in T2. Thus, it may be concluded that dragon fruit should be harvested at 28 days after flowering when peel colour is pink red, specific gravity (1.05), pupl:peel ratio 2.59 and TSS:acid ratio 48.20. Dipping fruits in 100 ppm sodium hypochlorite solution for 5 minutes, air dried and packed in transparent 0.2% perforated LDPE bags is the best treatment with minimum PLW, rotting and microbial activities retaining maximum sugars, ascorbic acid, crude protein, crude fibre, betalains, total antioxidant which extended the shelf life up to 8 days at ambient condition.EnglishThesis