Response mechanisms induced by exposure to high temperature in tomato genotypes and development of suitable management strategies for enhancing thermo- tolerance (Record no. 291778)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 07871nam a22002057a 4500 |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 571.2 |
| Item number | AMR/RE Ph. D |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Amrutha Vijayakumar |
| 245 ## - TITLE STATEMENT | |
| Title | Response mechanisms induced by exposure to high temperature in tomato genotypes and development of suitable management strategies for enhancing thermo- tolerance |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc | Vellayani |
| Name of publisher, distributor, etc | Department of Plant Physiology, College of Agriculture |
| Date of publication, distribution, etc | 2024 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 215p. |
| 502 ## - DISSERTATION NOTE | |
| Dissertation note | Ph. D |
| 520 3# - SUMMARY, ETC. | |
| Abstract | 217 KERALA AGRICULTURAL UNIVERSITY COLLEGE OF AGRICULTURE, VELLAYANI DEPARTMENT OF PLANT PHYSIOLOGY DOCTORAL DEFENSE SEMINAR ABSTRACT Amrutha Vijayakumar Date: 07-10-2023 2020-21-014 Time: 11-11:30 am RESPONSE MECHANISMS INDUCED BY EXPOSURE TO HIGH TEMPERATURE IN TOMATO GENOTYPES AND DEVELOPMENT OF SUITABLE MANAGEMENT STRATEGIES FOR ENHANCING THERMOTOLERANCE. A study entitled “Response mechanisms induced by exposure to high temperature in tomato genotypes and development of suitable management strategies for enhancing thermo-tolerance” was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during 2020-2023 with the objective of physiological, biochemical and molecular characterization for high temperature tolerance to identify key traits controlling high temperature tolerance in tomato and to develop suitable management strategies to alleviate high temperature stress. The first experiment involved the evaluation of 58 tomato genotypes (2 check genotypes and 56 other genotypes) for temperature tolerance under field condition in summer season. These fifty-eight genotypes were evaluated for physiological and yield parameters under natural high temperature condition during summer season (February to May, 2022). From this varietal screening experiment, the best performing genotypes in terms of pollen viability, leaf membrane thermo-stability, chlorophyll fluorescence, number of fruits, fruit set % were selected to determine the critical physiological and biochemical characteristics regulating high-temperature tolerance in different tomato genotypes for high-temperature tolerance under high-temperature circumstances. During the Kharif months of 2022, from June to September, three tolerant and three susceptible genotypes from the first varietal screening field experiment were assessed both under high temperature (36 +/- 2°C) and ambient circumstances. The experiment was set up using a completely randomized design (CRD), with three replications of each of the two treatment levels-control and high-temperature stress. Research demonstrated that factors, such as pollen viability (PV), cell membrane stability (LMT), nitrate reductase (NR) activity, antioxidant enzymes, and their impact, has shed information on the ability of plants to tolerate stress caused by high temperatures. 218 Genotypes like Vellayani Vijay, Kashi Vishesh and Anagha showed better performance under heat stress conditions, by regulating some physiological parameters like higher PV, LMT, PR, higher rates of production of antioxidant enzymes (superoxide dismutase, sucrose phosphate synthase, invertase, nitrate reductase) and yield related observations like fruit set percentage, average fruit weight were also high. These characteristics can be considered as the key physiological, and biochemical traits controlling high temperature tolerance in tomato. By creating a variety utilizing genetic techniques, genotypes with higher thermotolerance, and thus negative effects of heat stress on tomatoes can be reduced. Under high temperature condition, Arka Vikas showed the highest exerted stigma length and there is significant variation for flower burning and flower drop among all the genotypes under study. With respect to yield, biochemical and physiological data the changes in the tolerant and susceptible genotypes under HS conditions can be noted. Tolerant genotypes (Kashi Vishesh, Vellayani Vijay) exhibited reduction in physiological characteristics like LMT (5-7 %), PV (10-15%), total chlorophyll content (3-5%), PR (6- 17%), and an increase in SC (6-9%), CF (2-3%). In the similar way, biochemical parameters in case of tolerant genotypes showed a reduction in SOD content (16-19%), SPS (3-10 %), INV activity (3-7 %), NR activity (4-10%), total sugars (23-30%), and an increase in anthocyanin (12-20%), flavanol (2-4%) were also recorded. Under heat stress conditions only those genotypes that are tolerant produced higher fruit yield per plant than the susceptible ones. Similarly, reduction in features like LMT (10-22 %), PV (30-45 %), chlorophyll content (11-14%), PR (20-32%), and increase in SC (11-22%) and CF (5-7%) has been observed. Reduction in biochemical parameters under HS were SOD content (27-50%), SPS (11-43 %), INV activity (11-13 %), NR activity (14-19%), total sugars (29-37%), and an increase in anthocyanin (5-9%), flavanol (1-2%) were noticed in susceptible genotypes like Arka Vikas, PKM-1 and Pusa Rohini under HS. The reduction in fruit set % ranged from 30-50% in tolerant genotypes and was ranging from 80-90% in susceptible ones. The yield attributes viz., number of fruits per plant, fruit set %, average fruit weight (g), yield per plant (g) were significantly lower for varieties like Arka Vikas, PKM-1 and Pusa Rohini. The reduction in number of fruits per plant was nearly 30-40% in tolerant group whereas it was 80-98% in susceptible group. The intensity of fruit drop increased at a range of 25-30% in tolerant genotypes whereas it increased by 50-80% in susceptible genotypes. The reduction in yield per plant reduced in both tolerant and susceptible genotypes and this ranged between 25-40% and 80-90% respectively when plants were exposed to heat stress conditions. 219 An experiment was undertaken to develop suitable management strategies to alleviate high temperature stress. One of the susceptible genotypes (Arka Vikas) and two tolerant genotypes (Vellayani Vijay, Kashi Vishesh) were selected from previous experiment and were evaluated for the study to develop the best suitable management strategy to alleviate high temperature stress. The experiment was set up using CRD with two factors, factor 1 being the two stress levels (control and high temperature (36+/-2oC) and the second factor being the nine treatments- T1: Salicylic acid (1.0 mM), T2: Salicylic acid (1.5 mM), T3: Spermidine (2.5 mM), T4: Spermidine (4.0 mM), T5: Brassinosteroids (0.3 mM), T6: Brassinosteroids (0.6 mM), T7: Piriformospora indica, T8: Absolute control and T9: Control. The treatments, T1 to T6 were applied as foliar spray at the flowering stage, T7 was inoculated to the roots by co-cultivation method. The best management strategy to be recommended is spraying BR (0.3 mM) and BR (0.6 mM) at the floral initiation stage to alleviate high-temperature stress. PR, LMT, PV, fruit number, and average fruit set % were improved by these treatments, antioxidant production and its activity, flavonol, anthocyanins and total sugars showed significant increase in its content. Early flowering and fruiting were one of the significant impacts of P. indica inoculation to roots in both tolerant and susceptible genotypes. The gene expression analysis of MYB33, HSFA1a, HSFB2a and alpha-amylase transcription factors which are imparting high-temperature stress tolerance showed that all the genes were upregulated under stress conditions for tolerant genotypes whereas genes-alpha amylase, HSFA-1A, HSFB-2a were downregulated under stress conditions and MYB33 gene were upregulated under stress. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Plant Physiology |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Tomato genotypes |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Thermo- tolerance |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM | |
| Topical term or geographic name as entry element | Tomato |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Beena, R (Guide) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | https://krishikosh.egranth.ac.in/handle/1/5810220096 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Item type | Theses |
| Not for loan | Collection code | Permanent location | Current location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Koha item type |
|---|---|---|---|---|---|---|---|---|---|
| Not For Loan | Thesis | KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2025-01-07 | 571.2 AMR/RE Ph. D | 176179 | 2025-01-07 | Theses |