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ThesisItem Embargo Effect of glutathione, proline and magnesium sulphate on seed vigour and antioxidants in sorghum (Sorghum bicolor [L.] Moench) under salt stress conditions(Punjab Agricultural University, 2024) Maheshwari, Akshita; Dr. Namarta GuptaIn the present investigation, effect of glutathione, proline and magnesium sulphate was studied on seed vigour and antioxidant defense system under salt stress conditions in sorghum (Sorghum bicolor [L.] Moench) cvs. SL 45 and SL 46. The salt stress had adverse effects on seed germination and seed vigour parameters. Seeds of sorghum were treated with proline (25ppm, 50 ppm and 100 ppm), glutathione (100 ppm, 250 ppm and 500 ppm) and magnesium sulphate (10 ppm, 25 ppm and 50 ppm) and were subjected to salt stress of 50 mM and 75 mM. Different parameters were recorded from seedlings after 10 days of germination. The seed treatments increased the physiological (percent germination, seedling length, seedling biomass, vigour index I and II) and biochemical parameters (total soluble sugars, total soluble proteins, proline content and activities of antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase) of seedlings as compared to control. However, malondialdehyde content decreased with seed treatments at all salinity levels in both the cultivars. The results showed that proline 100 ppm, glutathione 500 ppm, magnesium sulphate 50 ppm were more effective than proline (25 ppm, 50 ppm), glutathione (100 ppm, 250 ppm), magnesium sulphate (10 ppm, 25 ppm) respectively. Thus, the application of proline, glutathione and magnesium sulphate could play an important role in improving the salt stress tolerance by their osmoprotective role.ThesisItem Open Access Evaluation of flag leaf characteristics in relation to spike quality and corm production in gladiolus (Gladiolus grandiflorus L.)(Punjab Agricultural University, 2024) Ramandeep Kaur; Dr. Shalini JhanjiThe present investigation entitled “Evaluation of flag leaf characteristics in relation to spike quality and corm production in gladiolus (Gladiolus grandiflorus L.) was conducted at the Research Farm of the Department of Floriculture and Landscaping, Punjab Agricultural University, Ludhiana during 2022-2023. The genotypes/varieties were evaluated for distinctiveness, uniformity and stability (DUS). Significant differences among the genotypes were recorded for studied morphological and post harvest quality parameters. The cluster analysis grouped the genotypes/varieties into two major clusters which were further subdivided into two subclusters each. Cluster Ib (Punjab Pink Elegance, Punjab Lemon Delight, Punjab Glance, etc) performed best in terms of desirable morphological traits while cluster IIa (Pusa Gunjan, Pusa Kiran, Punjab Dawn, etc) was found to have performed least in terms of various morphological characters. Cluster analysis also revealed that Punjab Glance and Punjab Glad 3 lied in different clusters and differed based on flag leaf length, spike length, spike weight, corm weight, days to initiation and complete spike emergence due to which these two varieties were selected for evaluation of flag leaf characteristics in relation to spike and corm production during different spike developmental stages. With advancement in developmental stages, there was significant growth of flag leaf, spike and corm. In comparison of Punjab Glance and Punjab Glad 3, Punjab Glad 3 had comparatively greater flag leaf length, width, area, weight, total leaf weight, area, spike length, rachis length, spike weight, rachis weight, spike diameter, lamina thickness, epidermal thickness, mesophyll thickness and stomatal index but in terms of corm traits, Punjab Glance had greater number of corms, corm weight, corm diameter and number of cormels. Punjab Glad 3 had comparatively greater membrane stability (MS), relative water content (RWC), total soluble sugars (TSS), total soluble proteins (TSP), sucrose content, starch content, activity of acid invertase, neutral invertase and sucrose synthase than Punjab Glance in both flag leaf and spike while in corm Punjab Glance had greater MS, RWC, TSS, TSP, sucrose content, starch content, activity of acid invertase, neutral invertase and sucrose synthase. Punjab Glad 3 had greater flag leaf length and width which led to longer spike but less corm development as maximum assimilates were translocated to spike while in case of Punjab Glance though it had shorter spike but the corm in this case had greater sink strength which led to better corm development.ThesisItem Embargo Seed treatment studies for improving seed germination and vigour in quinoa (Chenopodium quinoa Willd.) genotypes(Punjab Agricultural University, 2024) Rajvir Singh; Dr. Navjyot KaurThe present study entitled „Seed treatment studies for improving seed germination and vigour in quinoa (Chenopodium quinoa Willd.) genotypes‟ was conducted in the Plant Physiology Laboratory, Office of Director (Seeds), Punjab Agricultural University, Ludhiana during 2022-2023. In this study, fifty quinoa genotypes were screened for germination parameters i.e. germination (%), seedling length, seedling fresh weight, seedling vigour index I and II, mean germination time and speed of germination using “between-paper” method. One genotype namely EC 896071 recorded the highest germination i.e. 83.8%. Other genotypes which exhibited germination higher than 40% were EC-896076 (70.5%), EC- 896063 (53.3%), EC-896081 (53%), EC-507739 (43.8%), and EC-896091 (42.5%). Majority of genotypes (44) recorded germination in the range of 8.5-40%. On the basis of performance in Experiment I, six quinoa genotypes viz., EC-507739, EC-896063, EC-896071, EC-896076, EC-896081 and EC-896091 were selected for seed treatment studies for enhancing the germination and seedling vigour. In Experiment II, seed treatments were given to seed by priming and scarification methods i.e. hydro-priming, halo-priming, hormo-priming, acid scarification and hot water scarification. Hydropriming for 2 hrs recorded the highest improvement in mean germination time, speed of germination, germination (%), seedling vigour index I and II. From this study, 2 hour soaking of seed was standardized for other seed treatments also. Seeds were also primed with Mg(NO3)2, KNO3, KH2PO4, H2O2, CaCl2, K2HPO4, ZnSO4, GA3, kinetin, ethrel and scarified with 5% H2SO4 and hot water. A comparison of hydropriming with all other chemical and scarification treatments revealed that hydropriming with 2 hour duration is the best treatment for improving germination and vigour of quinoa genotypes.ThesisItem Restricted Physiological traits associated with grain weight in 5U/5A wheat chromosomal segment substitution lines under waterstress conditions(Punjab Agricultural University, 2024) Kulveer Kaur; Dr. Navita GhaiThe scarcity of water is a severe environmental constraint to plant productivity. Water-stress affects wheat growth and development at various stages in its life cycle. The present investigation, entitled "Physiological traits associated with grain weight in 5U/5A wheat chromosomal segment substitution lines under water-stress conditions", was carried out during the Rabi seasons 2020-21 and 2021-22 in the experimental area and laboratories of the Department of Botany, Punjab Agricultural University, Ludhiana. The plant material used for the experiment was a disomic substitution line DS5Ut(5A), wheat cultivar Pavon Ph1b mutant, hexaploid wheat cultivar WL711 and 91 chromosomal segment substitution lines (CSSLs) derived from their three-way cross. 91 CSSLs along with parents and relevant checks were sown at the recommended time of sowing under two irrigation regimes (irrigated conditions and rain-fed conditions). The CSSLs, parents and checks varied significantly and were negatively affected by water-stress for traits viz., days to booting, days to heading, days to flowering, days to physiological maturity, awn length, spike length, peduncle length, plant height, spikelets per spike, thousand grain weight, grain weight per spike and grain yield under rain-fed conditions. Genome wide association studies were carried out to detect genomic regions responsible for water-stress tolerance CSSLs which revealed fifty-five highconfident markers associated with stress tolerance for traits studied. The current study suggested that 5U-24, 5U-26 and 5U-27 are water-stress tolerant and also CSSL 5U-26 outperformed check variety PBW725, parent DS5Ut(5A) and other CSSLs by maintaining grain yield besides exhibiting an increase in thousand grain weight under water-stress conditions. In 5U-26, maintenance of water content, canopy temperature depression, increased amounts of compatible solutes (proline, glycine betaine and soluble sugars), decreased cell damage (in terms of malondialdehyde and hydrogen peroxide contents), lower reduction in photosynthetic activity (chlorophyll content, quantum yield of PSII and nonphotochemical quenching) and enhanced stem reserve mobilization might have contributed towards maintenance of grain yield along with increased thousand grain weight under waterstress conditions. Therefore, 5U-26 may act as a potent germplasm donor in future breeding programs to enhance water-stress tolerance in wheat.ThesisItem Restricted Effect of foliar application of humic acid against terminal heat stress in wheat (Triticum aestivum L.) genotypes(Punjab Agricultural University, 2023) Aishwarya Rawal; Aparjot KaurTerminal heat stress in wheat (Triticum aestivum L.) is a major threat on account of global climate change that significantly affects the yield. To investigate the present study, wheat varieties viz PBW 725 (timely sown) and PBW 752 (late sown) were sown in randomised block design as per PAU‟s package and practice in PVC cylinders (PAU) and field (RRS, Bathinda) conditions. Foliar application of two concentration of humic acid (2000 ppm and 4000 ppm) was done ten days prior to tillering, booting and flowering stage. The treatment without any spray served as control. At all stages morpho- physiological and biochemical parameters were recorded whereas yield and yield attributes were recorded at maturity. The present study found that foliar spray of 2000 ppm and 4000 ppm humic acid significantly increased plant height in flowering and grain filling stages. The booting stage exhibited the maximum dry weight (0.089 g) in PBW 752 at 4000 ppm dosage. The 4000 ppm foliar spray significantly increased the relative growth rate of PBW 725 (15 %) at Bathinda. Humic acid reduced electrolyte leakage in PBW 725 and PBW 752 plants at Bathinda, and increased cellular viability (72 %) along with leaf relative water content (99 %) at 4000 ppm foliar spray The chlorophyll a (25.84 mg g-1 FW), chlorophyll b (10.96 mg g-1 FW), total chlorophyll content (33.5 mg g-1 FW) and carotenoids (10.46 mg g-1 FW) spiked after 4000 ppm foliar spray of humic acid. The flowering stage showed an unprecedented value of total soluble sugars for PBW 725 (49.8 mg g-1 FW) on 4000 ppm treatment of humic acid. The study found that starch content (52.9 mg g-1 FW) increased significantly PBW 752 after 4000 ppm of foliar spray of humic acid. The highest α-amylase activity (133.1 nanomoles of glucose formed min-1 g-1 FW) was observed in PBW 752 at booting stage after 4000 ppm of foliar spray of humic acid. On the other hand, foliar spray of humic acid did not depict any significant effect on yield components.ThesisItem Embargo Effect of biochar and bacterial endophytes on salinity tolerance in oats (Avena sativa L.)(Punjab Agricultural University, 2023) Arshdeep Kaur; Gupta, NamartaThe present investigation was carried out to study the effect of biochar and plant growth-promoting bacterial endophytes for salt tolerance in oats (Avena sativa L.). Forty four morphologically distinct salinity-tolerant endophytic bacteria were isolated from the leaf, stem and root samples of oats on nutrient agar with 2.5% NaCl and screened for the production of ammonia, auxins, siderophore and HCN; solubilization of Ca3(PO4)2, ZnO, Zn3(PO4) and ZnCO3 and salt tolerance up to 12% NaCl. Bacterial isolates showing high salt-tolerance and plant growth-promoting traits were selected and tested for growth promotion of oats on 1% H2O agar plates. Three potential isolates were identified based on polyphasic approach as Enterobacter quasiroggenkampii O1SE4, Bacillus inaquosorum O3SE2 and Bacillus safensis O4SE1. The SEM analysis showed the colonization of the plant tissues by all the three bacterial strains. Total 25 genotypes were screened for germination parameters viz. percent germination, shoot length, root length, seedling length, fresh weight, dry weight, vigour index I and II, proline, SOD, POD and CAT under salt stress conditions and were grouped into highly salt tolerant, moderately salt tolerant, moderatly salt sensitive and highly salt sensitive. Among seed treatments, the combination of biochar (2%) and Bacillus safensis maximally improved the above parameters as compared to the other treatments of Enterobacter quasiroggenkampii, Bacillus inaquosorum and biochar (1%). The evaluation of biochar and bacterial strains was done in two salt tolerant and two salt sensitive genotypes grown in the pots. The highest plant height, SLW, NAR were observed with the bacterial treatment (Bacillus safensis) + biochar (2%). Among biochemical parameters chlorophyll, carotenoid, total soluble sugar, starch, total soluble protein and free amino acids along with activities of antioxidant enzymes SOD, POD and CAT were enhanced by the application of Bacillus safensis and biochar (2%). Na+/K+/Ca2+/Mg2+ homeostasis was maintained by biochar and bacteria application. In conclusion, it is stated that the combined use of biochar and halotolerant endophytic bacteria can be used for improving the crop growth under salt stress in oats.ThesisItem Embargo Morpho-anatomical and biochemical characterization of interspecific cotton (Gossypium spp.) derivatives for jassid tolerance(Punjab Agricultural University, 2023) Garg, Nitika; Gupta, NehaThe present investigation entitled “Morpho-anatomical and biochemical characterization of interspecific cotton (Gossypium spp.) derivatives for jassid tolerance” was undertaken to evaluate the performance of backcross derivatives carrying genomic introgressions of G. arboreum in G. hirsutum background for jassid tolerance. Various leaf morpho-anatomical characteristics such as gossypol glands, trichome density on both young and mature leaves, extrafloral nectaries, distance between lower epidermis to phloem, leaf thickness in stelar and extra-stelar region were studied in parents G. arboreum LD 491, G. hirsutum LH 2107 and their BC1F2 derivatives find out their relationship with jassid (Amrasca biguttula) tolerance on cotton. Present research revealed non-significant differences for gossypol glands and extrafloral nectaries among the parents. The backcross derivatives exhibited a wide genetic variation for gossypol glands, trichome density and other studied morpho- anatomical traits. Trichome density was significantly higher in G. arboreum (156.02±4.36) than G. hirsutum cv. LH 2107 (92.24±2.03). However, trichome counts on young and mature leaves depicted a significant decline in trichome density with maturity among parents and backcross derivatives. The backcross derivatives exhibited wide range of leaf thickness from 0.25 mm to 0.82 mm in stelar region whereas in extra-stelar regions, the BC1F2 individuals had leaf thickness from 0.09 mm to 0.30 mm. The distance between lower epidermis to phloem was highest in G. arboreum (0.26 mm) than G. hirsutum (0.23 mm). The backcross population had a range of 0.13 mm - 0.36 mm for distance of lower epidermis to phloem among the individuals. No direct relationship between above mentioned morpho-anatomical traits and jassid nymph count on was depicted in our study. In addition, various biochemicals such as chlorophyll and carotenoid, sugars, starch, gossypol, phenolic, tannins, flavonoids, lignin and salicylic acid contents of leaf tissue were also determined in G. arboreum and G. hirsutum parents and backcross population at maximum jassid infestation. Tolerant entries (belonging to Grade I and II) had significantly higher contents of chlorophyll and carotenoid, soluble sugars, total phenols, tannins, and flavonoids than susceptible group of entries (with grade IV). Starch and salicylic acid content was significantly lower in the tolerant group of genotypes than susceptible ones. Our study concluded that higher levels of the secondary metabolites (phenols, tannins, flavonoids) and maintained production of sugar assimilates might contribute towards jassid tolerance of interspecific derivatives belonging to Grade I and Grade II.ThesisItem Embargo Growth and physiological characters in staygreen wheat introgression lines under post anthesis drought stress(Punjab Agricultural University, 2022) Shelly; Bedi, SeemaClimate change is a significant threat to the majority of agricultural crops around the world. In wheat, drought stress at post-anthesis stage is known to affect the yield and yield attributes. Genotypes with stay green trait retain the chlorophyll for longer duration and have a positive association with yield attributing traits particularly in crops experiencing abiotic stress. In this study, some stay green introgression lines were evaluated for germination under water stress conditions and yield and yield related traits under post-anthesis drought stress Under laboratory conditions, the genotypes were screened by creating drought stress using PEG 6000. The genotypes were analyzed on the basis of germination percentage, shoot length, root length, root: shoot ratio, seedling fresh and dry weight, seedling relative water content and vigour index. The genotypes BWL 4421, BWL 4423, BWL 4431 and BWL 4435 performed well. In the field the genotypes were analyzed on the basis of yield and yield attributing traits. The genotypes BWL 4431 and BWL 4435 performed well in the laboratory experiment as well as in the field experiment. Overall, the stay green lines performed better than the non-stay green check (Unnat PBW 550) in yield attributing traits and also yield by maintaining yield and other components.ThesisItem Embargo Evaluation of morpho-physiological and metal accumulation potential of Salix alba L. and Toona ciliata M. Roemer grown on heavy metal contaminated soils(Punjab Agricultural University, 2022) Ravneet Kaur; Sharma, RajniThe present investigations were carried out to study the effect of lead (Pb), cadmium (Cd) and their combinations (Pb+Cd) on morpho-physiological and metal accumulation potential of Salix alba and Toona ciliata during 2020 and 2021. Heavy metals induce negative effect on morphological and biomass attributes of both species, but Toona showed better survival percentage (>95%) than Salix (<55%) even at higher concentrations of Pb300 and Cd25. The accumulation of proline, total soluble sugars, total soluble proteins along with increased antioxidant enzyme activities are responsible to enhance tolerance in both species. On the basis of phytoremediation efficiency evaluation factors such as bioconcentration factor (BCF) and translocation factor (TF), Salix alba can be categorized as excluder plant for Pb and Cd with higher metal accumulation in roots than shoots (BCF>1, TF<1), while Toona ciliata can be categorized as hyperaccumulator with more Pb and Cd accumulation in the shoots than roots (BCF>1 and TF>1). Further, heavy metal translocation and accumulation decreased in combinations as compared to single element application suggesting the antagonistic relationship among both metals. Pb and Cd negatively affect the plant nutrient content either by affecting their translocation or by decreasing nutrient availability in soils. Anatomical studies showed significant alterations in stomatal pore size, stomatal density and trichome density due to heavy metal toxicity in both Salix and Toona. Field emission scanning electron microscopy and energy dispersive x-ray spectroscopy (FESEM-EDS) results confirmed the Pb and Cd accumulation sites in the leaves and root tissues of plants. Fourier transformed infrared (FTIR) spectroscopy analysis revealed that Pb and Cd accumulation in plants induced changes in carboxy, amino, hydroxyl and phosphate groups that ultimately caused alteration in physiological functioning in plants. Conclusively, both Salix alba and Toona ciliata have potential to be used as remediation species for Pb and Cd contaminated soils.
