Effect of Different Pre-Sowing Treatments on Germination Characteristics of Strawberry Guava (Psidium cattleainum Sabine)

Aim: The aim of the present study was to investigate the effect of different pre-sowing treatments on germination characteristics of strawberry guava (Psidium cattleainum Sabine).Study Design: The experiment consisted of eleven treatments and three replications laid out in a Completely randomized design (CRD).Place and Duration of Study: The study was conducted at Orchard Nursery, Department of Fruit Science, Horticulture College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during April-June 2023.Methodology: Seeds of Psidium cattleainum (strawberry guava) were collected from guava germplasm from an orchard and treated with different pre-sowing chemicals. After pre-sowing treatment, the seeds were sown and various germination characteristics and growth parameters were observed and recorded.Results: The seeds treated with GA3 500 ppm for 30 minutes took minimum days to germinate (20), with higher germination percentage (79.33%), maximum vigour index I, and vigour index II (708.6 and 584.23). The growth parameters such as seedling height, stem girth,and number of leaves, primary root length, number of lateral roots were recorded higher in GA3 500 ppm followed by Thiourea 1%.The biomass production of seedlings was also higher in seeds treated with GA3 500 ppm.Conclusion: The seeds treated with GA3 500 ppm for 30 minutes recorded higher germination characteristics, growth parameters and biomass production. So for quicker propagation of strawberry guava to be used as rootstock, seeds can be treated with 500 ppm GA3 to obtain the large number of seedlings for the use of rootstock.

Evaluation of Easy and Economic Protocols for High Quality Genomic DNA Extraction and Sex Determination in Papaya Using SCAR Markers

Rapid and precise identification of three sex types (male, hermaphrodite and female flowers) is the key in achieving good returns in papaya (Carica papaya L.) cultivation. This study presents a simple, reliable, fast and cost-efficient DNA isolation protocol and a rapid and precise method of sex determination in papaya. Three DNA isolation protocols viz., CTAB method, Modified Dellaporta method and BioBasic DNA isolation kit were comparatively evaluated for their simplicity, economic, DNA quantity and purity. Among them, CTAB method was regarded as relatively economic, with a cost of Rs. 11.80943 per sample with higher amount of DNA (4667.4 µg/ µl). However, it was noticed that DNA isolation with the BioBasic kit was fastest method, which took only 6 hours 7 minutes. On the other hand, relatively better DNA purity was noticed with the Modified Dellaporta method (average ratio of absorbance at 260 nm and 280 nm range between 1.8-2.0) and yielded clear, intact and distinct DNA bands. Hence, Modified Dellaporta method is suggested as an ideal DNA isolation protocol for papaya. Molecular markers (such as SCAR derived from RAPD T12, W11, NAPF-2 and PKBT-4) were employed in this study to identify the sex type and they have successfully distinguished between male and hermaphrodite plants in both dioecious and gynodioecious varieties; especially, NAPF-2 has successfully distinguished male in dioecious varieties. Evaluation of different kinds of molecular markers has shown that the SCAR marker T12 can be used as reliable marker for rapid and precise identification of papaya sex type.

Effect of Inorganic Fertilizer and Spacing on the Plant Growth of Dragon Fruit (Hylocereus costaricencis) under Tamil Nadu Agro-Climatic Conditions

The dragon fruit (Hylocereus costaricencis) is a new emerging fruit crop, there is very less information available on the spacing and fertilizer dose requirements of this crop so the present study was carried out to find the effect of fertilizer doses, spacings, and interaction effect of both on plant growth of dragon fruit (Hylocereus costaricencis) at the Orchard, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore. during the year 2022. The design of the experiment was a split plot with four main plots viz. M1 = 3.5 x 2.0 m2, M2 = 3.0 x 3.0 m2, M3 = 3.0 x 2.5 m2, M4 = 2.5 x 2.5 m2 and six sub plots viz. S1 = N540 P420 K360, S2 = N495 P385 K330, S3 = N450 P350 K300, S4 = N340 P260 K225, S5 = N225 P175 K150, S6 = N0 P0 K0 g per pillar was applied and replicate four times. A significant difference was observed in terms of vine length (m), cladode girth (cm), cladode length (cm), and cladode number when different doses of fertilizers were applied. The highest vine length (2.96), cladode girth (24.52), cladode length (67.21), and number of cladodes (67.48) were observed in S3 (N450 P350 K300). Similarly, the highest vine length (2.503) and cladode girth (19.78) were observed in M4 (2.5 x 2.5 m2). The highest cladode length (67.47) was observed in treatment combination M2S3. Hence, the application of fertilizer dose S3 (N450 P350 K300) and adoption of spacing M4 (2.5 x 2.5 m2) is good to enhance the vegetative growth characters of dragon fruit under Tamil Nadu conditions.

Influence of Fruit Bagging on the Physical Qualities and Shelf Life of Mango cv. Alphonso under Ultra-High-Density Planting

The present experiment was conducted to study the effect of preharvest fruit bagging on the physical parameters and shelf life of mango cv. Alphonso during 2023. Mango fruits were bagged 35 days after the fruit set with various types of bags viz: T1: Brown paper bag; T2: Double layered bag; T3: Transparent bag; T4: Non-woven bag; T5: Butter paper bag; T6: Control (no bagging). The experiment was conducted in Randomized Block Design (RBD) with six treatments and four replications. The result indicated that preharvest fruit bagging had a significant effect on physical parameters, shelf life and days required for harvest after bagging. Bagging with Double layered bag increased fruit retention (75.03%), fruit length (9.35cm), fruit weight (295.36g), pulp weight (228.30g), shelf life (18.5 days) and decreased physiological loss of weight (8.16%). Therefore, preharvest fruit bagging improved fruit retention, physical parameters and shelf life in mango cv. Alphonso.

Role of Exogenous Melatonin in Enhancing Shelf Life of Traditional Banana Varieties

Aims: An experiment was conducted to examine the effect of various concentrations of melatonin on post harvest weight loss and shelf life of three traditional banana varieties viz. Ney Poovan, Nendran and Red Banana.Study Design: Completely Randomized Design.Place and Duration of Study: Post Graduate laboratory, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during 2022.Methodology: Banana hands were dipped in 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mM melatonin for 15 minutes and were stored at ambient temperature. The hands dipped in water were treated as control. Observations on physiological weight loss and shelf life were recorded till the fruits remained marketable.Results: The results depicted that fruits immersed in 1.0 and 1.5 mM melatonin for 15 minutes recorded lower weight loss (31.56, 30.55 and 24.90%) on 11th, 11th and 12th day of storage and longer shelf life by 3, 2.67 and 2.67 days in Ney Poovan, Nendran and Red Banana respectively.Conclusion: The effects of melatonin were due to its efficiency in reducing transpiration and respiration and thereby lowering weight loss. The lowered metabolic activity not only mitigated weight loss but also maintained firmness and turgidity of the fruits and thereby prolonging the storability. It was evident from the results that melatonin treatment could be a good practice for extending postharvest life of banana by reducing the physiological loss in weight simultaneously maintaining the appearance.

Physio-Chemical Changes during Ethrel Treatment of Mango cv. Alphonso under Different Temperature Regimes

Aim: Mango (Mangifera indica L.) is the second most consumed fruit which belongs to the family Anacardiaceae. Ripening in mango (climacteric fruit) is hastened by application of ethrel. The experiment was conducted to study the effect of different temperatures during ethrel treatment on shelf life and quality of mango cv. Alphonso.Study Design: The experiment consisted of three treatments and seven replications laid out in Completely randomized design (CRD).Place and Duration of Study: The study was conducted at Department of Fruit Science, Horticulture College and research Institute, Tamil Nadu Agricultural University, Coimbatore during 2022-2023. Methodology: Mango cv. Alphonso was subjected to ethrel treatment in three different ripening chambers having different temperatures viz., T1 – silpaulin chamber (33°C), T2 – zero energy cool chamber (26°C), T3 – cold chamber (22°C) for a period of 24 hours. After ethylene treatment, the fruits were stored at ambient temperature to study the ripening behaviour. Shelf life and quality parameters were observed and recorded. Results: The days taken for ripening was lesser (6 days) and the rate of conversion of quality attributes were higher in fruits subjected to ethrel treatment in silpaulin chamber. The quality attributes like TSS (22°Brix), acidity (0.25 %), TSS : acid ratio (88) were significantly higher in fruits treated in silpaulin chamber on the day of ripening. The physiological loss in weight was found to be significantly lesser in fruits subjected to ethylene treatment in cold chamber (6.56 %) and were on par with fruits treated in zero energy cool chamber (6.71%) whereas the firmness and shelf life were found to be significantly higher in cold chamber treated fruits (2.35 N, 15 days respectively) but firmness was on par with fruits subjected to ethylene treatment in zero energy cool chamber (2.21 N) on ripening. The overall acceptability of fruits in sensory evaluations was significantly higher in fruits treated in zero energy cool chamber (8.3) which was on par with fruits treated in cold chamber (8.1).Conclusion: The fruits treated in silpaulin chamber had better TSS, acidity and TSS: acid blend. The fruits treated in cold chamber were superior in shelf life and sensory score which was also on par with fruits treated in zero energy cool chamber. Hence zero energy cool chamber can be used as an alternative to cold chamber for ethrel treatment which would be cost effective, environment friendly and can be used by small traders and farmers.