Thumbnail Image

Thesis

Browse

20145
Reset filters
Subject: Botany × End date: 2014 × Start date: 2014 × Type: Thesis × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    ThesisItemOpen Access
    Morpho-physiological and biochemical characterization of a recombinant inbred line population of rice (Oryza sativa L.) under direct-seeded aerobic conditions
    (Punjab Agricultural University, Ludhiana, 2014) Cheema, Amandeep Kaur; Bedi, Seema
    Direct seeding of rice (Oryza sativa L.) is a resource conservation technology but at the cost of reduction in yield. In the present study, recombinant inbred lines (RILs) obtained from a cross between PR 120 x UPLRi 7 were sown as direct-seeded aerobic and conventional transplanted crops respectively for two seasons. Various morpho-physiological, biochemical and yield related traits were studied under the two conditions. In general, plant height, dry matter, crop growth rate, relative growth rate, leaf area and chlorophyll content were lower under direct-seeded aerobic conditions than under conventional transplanted conditions. Plant height and crop growth rate showed a positive correlation with grain yield and had a direct effect on grain yield. Dry matter accumulation did not show any significant correlation but had an indirect effect on grain yield. Relative growth rate, leaf area and chlorophyll content did not show any correlation or effect on grain yield. All the yield contributing traits viz., above ground biomass, total number of tillers per 0.5m row, number of fertile tillers per panicle per 0.5m row, spikelets per panicle, grain filling percentage, grain yield per 0.5m row, harvest index, 1000 grain weight were lower and sterile grain per panicle were higher in direct-seeded aerobic condition. Above ground biomass and harvest index showed correlation with yield and had a direct effect on grain yield under both direct-seeded aerobic and conventional transplanted conditions. In general, higher sugar, starch and proline content were detected in leaves of direct-seeded aerobic crop. Out of twenty RILs under study, Ae-RIL-B-158, showed highest proline and sugar contents. Interestingly, this RIL showed least reduction in yield when sown under direct seeded-aerobic condition as against conventional transplanted condition suggesting this RIL may be more tolerant to drought stress as it accumulated highest proline and sugars under direct-seeded aerobic condition. The development of aerenchyma was comparatively more in crop raised under conventional transplanted conditions than under direct-seeded aerobic conditions. UPLRi7 (parent) showed maximum aerenchyma under direct-seeded aerobic conditions while PR120 (parent) showed maximum aerenchyma formation under conventional transplanted conditions. Under both the sowing conditions, two high-yielding RILs (Ae-RIL-B-42 and Ae-RIL-B-44) had higher aerenchyma than the two low-yielding RILs (Ae-RIL-B-7 and Ae-RIL-B-117). These characters could be used as criteria for selecting RILs for incorporating into breeding programmes for yield enhancement.
  • Thumbnail Image
    ThesisItemOpen Access
    Physiological evaluation of source-sink relationships in soybean (Glycine max L. Merrill) genotypes under variable photoperiods
    (PAU, 2014) Dogra, Anil kumar; Kaur, Jagmeet
    Soybean is a short day plant. Both photoperiod and temperature control the duration of pre and post flowering phase and are expected to affect source-sink relationships. The present investigations were aimed at evaluating the relative performance of different maturing group of soybean genotypes with respect to different physiological and biochemical indices for higher productivity under variable photoperiods. To achieve the objectives, field experiments were conducted during kharif seasons of 2012 and 2013 at Punjab Agricultural University, Ludhiana. The experiment were laid out in randomised block design with three replications consisting of 15 genotypes to screen for various morpho – physiological traits, yield and yielding attributes in first year. On the basis of results obtained from the first year experimentation, two genotypes from early maturing genotypes and each of three from medium and late maturing genotypes were selected for biochemical analysis. Morpho-physiological parameters viz., leaf area, leaf area index, leaf and stem fresh and dry weight, net photosynthesis, growth efficiency, chlorophyll content, photochemical efficiency and transpiration rate were affected by photoperiods. Under both the photo-periodic conditions, the late maturing group genotypes maintained higher leaf area, biomass accumulation, leaf area index, photosynthetic rate and transpiration rate as compared to medium and early maturing genotypes leading to higher yield. Under longer photoperiod i.e. June sowing showed more metabolic status as compared to shorter photoperiod (July sowing). Nitrogen metabolizing enzymes viz., GOGAT, GS, GDH and NR activity showed varied response in leaf and stem. Highest activity of these enzymes was found in longer photoperiod as compared to shorter photoperiod. Carbon metabolizing enzyme- invertase also showed varied response in podwall and developing seeds. The activity of this enzyme increased in developing seeds and the highest activity was observed in late maturing genotypes. Finally, it can be concluded that for selection of better genotypes under variable photoperiods, the physiological parameters total dry matter, CGR, RGR, photosynthetic rate, chlorophyll content, LAI, SPLW, 100 seed weight, numbers of pods per plant and harvest index should be considered. These parameters were found to have significant positive correlation with seed yield. Of the evaluated 15 diverse maturing genotypes, the early maturing genotypes EC 457161, medium SL 983 and late SL 958 are superior in terms of yield as well as in other morpho-physiological traits. Of all genotype SL 958 performed the best.
  • Thumbnail Image
    ThesisItemRestricted
    Photosynthetic efficiency of wheat genotypes in relation to yield under terminal heat stress
    (PAU, 2014) Radhika; Thind, S.K.
    To evaluate the sensitivity or tolerance level of 40 wheat genotypes (assembled by CIMMYT and some Punjab cultivars as checks) a laboratory experiment, the two periodic field experiments (2011-12 and 2012 -13) with normal sowing (November 30) and late sowing (December 30) and a pot experiment (2013-14) were conducted. The cell membrane thermo stability supported lesser lipid peroxidation (MDA) and minimal changes in mitochondrial activity (TTC) of heat tolerant genotypes which ultimately increased the survival potential under laboratory conditions after long term (24 hrs) heat shock treatment (40±2°C). Delay in planting under the field conditions caused significant decrease in the source sink activity, photosynthetic efficiency and grain growth parameters besides negative effects of terminal heat stress. The impact of this adversity could be clearly seen in the late maturing genotypes as they were prone to the leaf senescence under the late sown conditions. The studied correlation suggested that net assimilation rate, leaf area index, total chlorophyll, starch, pre-stem reserve mobilization, canopy temperature depression, net photosynthetic rate and transpiration rate were found to be effective traits defining wheat genotypes adapted to production systems prone to high temperature stress at 10 DAA. Early maturing genotypes were less affected while late maturing genotypes were found sensitive and were affected up to much more extent as these were highly dependent upon the reserves for the grain filling with the onset of the terminal heat stress. A significant difference was recorded among the genotypes for various quantity and quality contributing traits. An increase in seed protein content, wet gluten, dry gluten, gluten index and sedimentation value and the decrease in number of grains/ spike, seed weight/spike,1000 grains weight, grain hardness and moisture content was recorded under the late planting conditions. Under the pot conditions the tolerant genotypes had relatively higher and wider growth ratios, photosynthetic efficiency (net photosynthetic rate, stomatal conductance and Rubisco enzyme activity) and grain yield when these were subjected to the heat stress (40±2°C) for 8hrs at anthesis.
  • Thumbnail Image
    ThesisItemOpen Access
    Nitrogen Metabolism of Wheat Genotypes in Relation to Heat Stress Tolerance
    (PAU, 2014) Sanghera, Amritpal Kaur; Thind, S.K.
    In present study a set of wheat genotypes (40) have been evaluated for their potential to withstand heat stress. For this one laboratory experiment, two periodic field experiments (2011-12 and 2012 -13) with normal sowing (November 29) and late sowing (December 29) and a pot experiment (2013-14) were conducted. The cell membrane thermo stability supported lesser lipid peroxidation (MDA) and minimal changes in mitochondrial activity (TTC) of heat tolerant genotypes which ultimately increased the survival potential under laboratory conditions after heat stress (35 and 40±2°C). Delay in sowing date caused significant decrease in several physiological parameters viz., nitrogen use efficiency and grain growth and yield parameters. Nitrogen uptake efficiency (NupE), grain nitrogen utilization efficiency (GNutE), nitrogen remobilization efficiency (NRE) was significantly higher in timely sown and biomass nitrogen utilization efficiency (BNutE) was higher in late sown genotypes. Grain yield had positive correlation with NupE, GNutE, NRE and N partitioning in grain but negative correlation with BNutE, N partitioning in leaves and chaff indicating that N mobilization from leaves and chaff to the grain limited grain yield and GNutE. A significant increase in seed protein content and sedimentation value and the decrease in grain yield, biomass yield, plant height, harvest index, grain filling period, grain hardness and moisture content was recorded under the late sown conditions. Under the pot conditions relatively higher proline content, total amino acids, quaternary ammonium compounds and ascorbate content was recorded in heat stressed plants as compared to control. Yield contributing parameters (grain yield, grain weight plant-1, number of grain plant-1) showed significant reduction under heat stress. The genotypes G3, G4, G6, G7, G9, G10, G31 and G32 had sustained yield contributing parameters under heat stress better as compared with others.
  • Thumbnail Image
    ThesisItemOpen Access
    Nitrogen metabolism of wheat genotypes in relation to heat stress tolerance
    (Punjab Agricultural University, Ludhiana, 2014) Sanghera, Amritpal Kaur; Thind, S. K.
    In present study a set of wheat genotypes (40) have been evaluated for their potential to withstand heat stress. For this one laboratory experiment, two periodic field experiments (2011-12 and 2012 -13) with normal sowing (November 29) and late sowing (December 29) and a pot experiment (2013-14) were conducted. The cell membrane thermo stability supported lesser lipid peroxidation (MDA) and minimal changes in mitochondrial activity (TTC) of heat tolerant genotypes which ultimately increased the survival potential under laboratory conditions after heat stress (35 and 40±2°C). Delay in sowing date caused significant decrease in several physiological parameters viz., nitrogen use efficiency and grain growth and yield parameters. Nitrogen uptake efficiency (NupE), grain nitrogen utilization efficiency (GNutE), nitrogen remobilization efficiency (NRE) was significantly higher in timely sown and biomass nitrogen utilization efficiency (BNutE) was higher in late sown genotypes. Grain yield had positive correlation with NupE, GNutE, NRE and N partitioning in grain but negative correlation with BNutE, N partitioning in leaves and chaff indicating that N mobilization from leaves and chaff to the grain limited grain yield and GNutE. A significant increase in seed protein content and sedimentation value and the decrease in grain yield, biomass yield, plant height, harvest index, grain filling period, grain hardness and moisture content was recorded under the late sown conditions. Under the pot conditions relatively higher proline content, total amino acids, quaternary ammonium compounds and ascorbate content was recorded in heat stressed plants as compared to control. Yield contributing parameters (grain yield, grain weight plant-1, number of grain plant-1) showed significant reduction under heat stress. The genotypes G3, G4, G6, G7, G9, G10, G31 and G32 had sustained yield contributing parameters under heat stress better as compared with others.