Ploidy Determination in Banana Hybrids through Stomatal Studies and Chloroplast Count

Stomata are probably a viable taxonomy distinguishing feature. The study of stomata characteristics of synthetic banana hybrids and their parentage has been carried out. Ploidy determination is essential in banana breeding programs to understand the genetic makeup of hybrid plants. The purpose of this study was to determine the ploidy level of hybrids in contrast with the properties of plant stomata in synthetic banana hybrids with those of their parent plants. Therefore, by examining components such as stomata location, number of epidermal cells, number of stomata cells, stomata length, width, area, intensity and density, as well as chloroplast count, it is possible to compare and contrast the traits of synthetic banana hybrids and their parentage which have different genomes. The entire mount approach was used to make an incision for the purpose of observing stomata. By characterising the stomata traits of the synthetic hybrids and their parentage, the results were then descriptively and qualitatively assessed. Three different locations on the abaxial of the leaf were taken for the determination. The samples were collected from close to the petiole (R1), middle (R2), and distal end (R3), stomata were observed using the replica method. Results showed that more number of stomata was observed in R2of leaf abaxial. The chloroplast count in pairs of stomatal guard cells from the accessions was also measured. The chloroplast density was determined in pairs of stomatal guard cells from the accessions. Based on morphological descriptions, it was observed that 16.66% of the accessions were diploid, 50% were triploid and 33.33% were tetraploid. When considering the chloroplast count, the accessions were categorized into groups, certain accessions classified as tetraploids, others as triploids, and diploids.

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.

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.

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.