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20173
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Subject: Plant Physiology × End date: 2017 × Start date: 2017 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Studies on carbohydrate metabolism in wheat under drought and high temperature conditions
    (CCSHAU, 2017) Kirpa Ram; Munjal, Renu
    The present investigation was conducted to assess the effects of drought and heat stress conditions on carbohydrate accumulation and partitioning and identify physiological and biochemical traits related to accumulation and partitioning of carbohydrate under drought and heat stress conditions. The eight wheat genotypes (AKAW-3717, DHTW-60, C-306, HD-2967, HTW-11, WH-730 and WH- 1105) in RBD with 4 rows of 2m length with a 20×5 cm spacing within rows and plants respectively, were grown during rabi season of 2015-16 and 2016-17 at Field Research Area, Wheat & Barley Section, Department of Genetics & Plant Breeding. Effect of individual drought and high temperature and their combination on physiological, biochemical and yield parameters under timely, late and very late sown condition was studied. Reduction in response of drought and high temperature was observed in physiological parameters (relative water content, osmotic potential, water potential, chlorophyll content, chlorophyll florescence taken in flag leaf) and biochemical parameters (peduncle and penultimate internode) at anthesis and 15 days after anthesis. Reduction in physiological and biochemical parameters was more pronounced under D40+D65 and complete drought at 15 days after anthesis as compare to anthesis. Metabolite (glucose, fructose, sucrose, water soluble carbohydrate and cellulose) and enzyme (SuSy, INV, SBE, SDBE and AGPase) activity get reduced under drought and with combination of delayed sowing. Fast rate of decline both in peduncle and penultimate inter node was observed. Yield was found highly associated with physiological and biochemical behavior of stressed plant. Yield penalty was more in combination of delayed sowing and drought situation at different growth stage. Genotype DHTW-60, HD-2967 and WH-1105 found promising in overall performance under timely, late and very late with different drought & high temperature situation. Carbohydrate metabolic & enzymatic traits with water relation & chlorophyll related traits are best traits for selection of drought and high temperature tolerant genotype.
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    ThesisItemOpen Access
    Characterization of recombinant inbred wheat (Triticum aestivum L.) lines for heat tolerance using physiological traits and molecular markers
    (CCSHAU, 2017) Sunita; Munjal, Renu
    A mapping population of eighty lines derived from the cross between WH1021 (heat tolerant) × WH711 (heat susceptible) were genotyped and phenotyped under timely and late sown during 2015-16 and 2016-17 crop seasons. The present investigation was conducted to evaluate the various morpho-physiological traits, their association with each other and to explore of the SSR markers related with heat tolerance during terminal heat stress. Data were recorded for various morphological traits including plant height and stem solidness at 70 and 100 days after sowing, number of days to heading, number of days to maturity, number of tillers per plant, spike length (cm), number of spikelets per spike, grain yield per plant (g), biological yield per plant (g), number of grains per spike, 100-grain weight (g) and physiological traits observations were recorded at anthesis and 10 days after anthesis including canopy temperature, transpiration rate, photosynthetic rate, stomatal conductance, intrinsic water use efficiency, chlorophyll content and NDVI. HSI for grain yield was determined for heat stress effect assessment. Analysis of variance showed significant variation among genotypes and reveal the genetic diversity among RILs. CTAB method was used for DNA isolation. Total ninety four markers were used to detect polymorphism in parents out of which parental polymorphism was found 23.5%. Genetic diversity analysis of RILs and parents was done using NT SYS-pc software based on twenty two SSRs and Linkage map constructed using these 22 polymorphic markers consist of seven linkage groups. Composite interval mapping (CIM) identified 14 quantitative trait loci (QTL) with significant phenotypic variation. Out of fourteen QTLs two QTLs were detected for plant height at 70 days after sowing , two for days to heading, two for days to maturity, two for photosynthetic rate, one for transpiration rate, four for intrinsic water use efficiency (iWUE) and one for NDVI. Out of these QTL and photosynthetic rate were consistent and stable over the condition and year respectively. Photosynthetic rate reported maximum phenotypic variation (78.13%) flanked by the two markers barc24 & Xgwm102 with an interval of 27.9 cM. Two QTLs for iWUE were also consistent and stable flanked by the markers Xgwm512 & Xgwm448 with 35.5 cM interval another Xgwm512 also flanked the another QTL for iWUE with 5.2 cM interval. These markers can be useful for the improvement through marker assisted selection for developing the better genotypes for heat tolerance.
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    ThesisItemOpen Access
    Physiological indices of drought tolerance in barley (Hordeum vulgare L.) genotypes
    (CCSHAU, 2017) Rajkumar; Sharma, K.D.
    To study the effect of irrigation levels on barley (Hordeum vulgare L.), twenty barley genotypes were evaluated under normal (Two irrigations at tillering and anthesis each) and restricted irrigation conditions (one irrigation at tillering) in concrete drought plots during the 2014-15 and 2015- 16 at the Crop physiology field area, Chaudhary Charan Singh Haryana Agriculture University, Hisar. The experiments were laid out using RBD with three replications. The results from combined analysis of variance in both normal and restricted irrigation conditions indicated that there were significant differences among genotypes with regard to all the traits because of high variation among the genotypes. Drought stress decreased the phenological traits like days to flag leaf, days to heading, days to anthesis and days to physiological maturity. The significant reduction was observed in plant height, dry biomass, leaf area, LAI, LAD, SLA and CGR under restricted irrigation. Under restricted irrigation leaf water potential, osmotic potential, relative water content, CTD, chlorophyll stability, membrane stability, photosynthetic rate, transpiration rate, stomatal conductance and Fv/Fm also decreased in barley genotypes. On the other hand, there was an increase in free proline content, MDA content and enhancement of antioxidant defense system to scavenge excess ROS molecules to prevent cell from damage. The main antioxidant enzymes which showed altered activity were superoxide dismutase catalase, peroxidase and ascorbate peroxidise. Yield and its attributes were also reduced under restricted irrigation condition. The quality parameters i.e. protein content, husk content and malt yield were increased while β-Glucan content decreased under restricted irrigation. Finally, based on physiobiochemical traits, it was revealed that among the tested genotypes, BH 14-05 and BH 10-30 performed better in terms of physiological, biochemical and yield related traits under restricted irrigation condition. These results indicated that selecting more tolerant genotypes based on physiological traits was the way to overcome terminal water stress and can be used for further crop improvement programmes.