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ThesisItem Open Access Effect of inorganic fertilizers and bioinoculants on biochemical components, growth, yield of garlic (Allium Sativum L.) and nutrient status of soil(Punjab Agricultural University, Ludhiana, 2021) Mamta; Sharma, RajniGarlic (Allium sativum L.) is an economically important vegetable crop which is used worldwide for culinary and medicinal purposes. The present study was conducted on garlic variety “PG-18” in a randomized block design during 2019- 2020. There were nine treatments which included various percentages of inorganic fertilizers (100% NPK, 75% NPK and 50% NPK) in combination with bioinoculants (consortium I and consortium II). Results reveals that supplementation of 75% NPK along with bioinoculants (consortium I or consortium II) gave the superior results than control (100% NPK) for most of traits such as plant growth parameters (plant height, leaf length, leaf width, pseudostem length and bulb diameter), yield attributes (total yield, marketable yield, 50 cloves weight and number of cloves) and biochemical parameters (total soluble sugars, reducing sugars, total phenols and total soluble solids). Moreover, nutrient content (nitrogen, phosphorus and potassium) of leaves and bulbs of garlic increased by combined inoculation of different combinations of NPK along with bioinoculants. Integrated application of inorganic fertilizers along with bioinoculants improved soil’s physico-chemical (pH and organic carbon) and biological (dehydrogenase activity) properties. Most of the parameters i.e. plant growth, total yield, nutrient, biochemical and soil properties decreased when the dose of 50% NPK supplemented with bioinoculants. Therefore, it can be concluded that integrated utilization of these bioinoculants along with 75% NPK improves soil health and it also offers scope of reducing the application of inorganic fertilizers to garlic crop by 25% without any loss in bulb yield.ThesisItem Embargo Histological and physiological changes in developing seeds and fruit pericarp of pumpkin (Cucurbita pepo L.) grown during different seasons(Punjab Agricultural University, 2022) Bhavna; Chahal, Gagandeep KaurThe histological and biochemical changes in developing seeds and pericarp of pumpkin genotypes (hulled and hull-less) in different growing seasons were evaluated in the present study. Biochemical analysis of seed coat revealed that the proteins, lipids and starch content were decreased in the seed coat with advancement of seed development due to translocation of these components towards the seed cotyledon since cotyledon acting as dominant sink. The proteins, lipids and starch content were observed to be more in the seed cotyledon in season II (low temperature) which improved the seed quality and also increased the thickness of seed cotyledon. Further, histological studies of developing seeds also depicted that the seed cotyledon thickness was more in season II as the low temperature slowed the seed development and gave more time to seed for accumulation of biomolecules into seed cotyledon. The seed coat thickness was also found to be more in season II in both the genotypes due to increased content of primary wall components like cellulose, hemicellulose and pectin and their deposition is responsible for increasing the seed coat thickness. The seed length, diameter and hundred seed weight were also more in season II and might be caused by increased seed coat and cotyledon contents. The pectin, cellulose, hemicellulose and lignin contents were observed to be increased with development in the pericarp.The development of pumpkin seeds and fruits hastened in high temperature which decreased the seed quality, while the low temperature slowed the maturity process and enhanced the seed quality.ThesisItem Embargo Mitigation of salt stress by γ-amino butyric acid (GABA) and proline in maize (Zea mays L.)(Punjab Agricultural University, Ludhiana, 2022) Sharma, Sakshi; Gupta, NamartaThe present investigation was conducted to study the effect of proline and GABA on physiological and biochemical parameters at different on different salt stress levels in two varieties of J-1006 and J-1007 maize (Zea mays). The salt stress negatively affected the seed germination and seed vigour parameters. Seeds of both the varieties were subjected to different treatments viz. Proline (10mM and 20 mM) and GABA (100ppm and 500ppm) at salt stress level of 50mM, 75mM and 100mM NaCl. Various parameters were recorded from seedlings after 10 days of germination. The seed treatments positively affected the physiological parameters (percentage germination, seedling length, seedling biomass, seed vigour I and seed vigour II) and biochemical parameters (total soluble sugars, total soluble protein and activities of antioxidant enzymes viz. Catalase, peroxidase and superoxide dismutase) of treated seedlings as compared to control. However, a reduction was observed in malondialdehyde content continue to decreased with seed treatments at all salinity levels. The results recoded that proline 20mM and GABA 500 ppm were more effective than proline 10mM and GABA 500ppm respectively. Therefore, the application of seed treatments viz, proline and GABA could play an important role in mitigating the effect of salt stress.ThesisItem Open Access Improving seed longevity of maize (Zea mays L.) through desiccation and packaging materials(Punjab Agricultural University, Ludhiana, 2021) Sukhpreet Kaur; Navjyot KaurThe present study entitled “Improving seed longevity of maize (Zea mays L.) through desiccation and packaging materials” was conducted during 2020-21. The seeds collected four months after harvest were desiccated to different moisture levels i.e., 12, 10 and 8% followed by storage in different packaging bags viz., laminated polypropylene bags, non- aminated polypropylene bags and polyethylene bags. Seeds with 12% moisture content stored in cloth bags served as control. Seeds of different treatments were stored under ambient conditions for 12 months. Physiological parameters were observed at monthly intervals and biochemical parameters were observed at three months interval during storage period. Germination percentage, seedling dry weight, seedling vigour index I and II and speed of germination decreased with increase in storage period; whereas electrical conductivity and mean germination time recorded a gradual increase with increased storage duration irrespective of different seed storage treatments. It was observed that seeds stored in laminated polypropylene bags and non-laminated polypropylene bags, polyethylene bags as well as cloth bags maintained the germination above 90% up to 13 months and thus complied IMSCS. Gradual decrease in germination was recorded with increase in seed storage duration and no seed storage treatment could maintain germination above IMSCS after 13 months of seed storage. The seed moisture content recorded fluctuations in accordance with relative humidity present in environment in all the packaging materials but greater fluctuation was observed in seeds stored in cloth bags and polypropylene bags as compared to seeds stored in polyethylene bags. Various food reserves viz., sucrose, starch content, oil and total soluble proteins decreased with increase in storage period; while total free amino acids increased with increase in seed storage duration. There was gradual decrease in α-amylase activity with increase in seed storage duration irrespective of the seed storage treatments. Antioxidant enzymes viz., superoxide dismutase, catalase and peroxidase also recorded gradual decrease in their activities in all the packaging materials with increased seed storage duration. Protein profiling indicated that the intensity of electrophoretic bands corresponding to polypeptides of molecular weight 44 and 52 kDa was higher in fresh seeds as compared to 15 months old seeds stored in various packaging treatments. The present study suggests that polypropylene bags either laminated or non-laminated can be used as cost effective and durable packaging materials instead of cloth bags and polyethylene bags owing to their lesser cost and higher flexural strength.ThesisItem Restricted Effect of residue mulch and irrigation regimes on physiological and biochemical attributes of onion (Allium cepa L.)(Punjab Agricultural University, Ludhiana, 2022) Shinedeep Kaur; Dhingra, MadhuA field experiment was conducted during rabi season of 2020-21 to examine the effect of residue mulch on physiological, biochemical and yield attributes of onion under different irrigation levels in a split plot design with three irrigation regimes based on IW/CPE 0.8 (I0.8), 1.4 (I1.4), 2.0 (I2.0) in main plots and two mulch rates i.e. M0 (no mulch) and M6 (paddy straw mulch @ 6 t ha-1) in sub-plots. Mulching with paddy straw moderated the soil hydrothermal regime by significantly improving the soil moisture storage and lowering the soil temperature. Plant growth in terms of plant height, biomass, number and size of leaves was significantly better in most frequent irrigation regime and further enhanced with the application of mulch under all irrigation levels at all stages. Both the factors exerted a significant effect on plant water status with 19.21-26.54% and 6-14% increase in relative water content with irrigation and mulch, respectively. Amongst biochemical traits, total chlorophyll and total protein content were highest in I2.0 while total soluble sugars and total proline content were maximum in I0.8. Mulch application increased total soluble sugar and protein content in onion leaves under all irrigation regimes but decreased proline content. Weed infestation was lowered by 34.69% in mulched plots but increased with irrigation frequency. Mulch application also reduced the profile water use and total water use by 44.74 and 3.31%, respectively. Higher percentage of large sized bulbs was obtained in I2.0M6. Both irrigation and mulching significantly affected bulb quality with respect to total soluble solids. Water productivity was highest in I0.8 and mulched plots. Application of paddy straw mulch improved the bulb yield with more pronounced effect in least frequent irrigation regime. Higher bulb yield with mulch in I1.4 than no mulch in I2.0 indicated the saving of three irrigations.ThesisItem Open Access Physiological studies in pomegranate varieties differing in fruit crack incidence(Punjab Agricultural University, Ludhiana, 2021) Gurleen Kaur; Nirmaljit KaurFruit cracking is a major physiological malady of pomegranate (Punica granatum L.) that limits its productivity. The initiation of fruit cracking was observed initially in July and it continued till September. Among varieties, maximum cracking was observed in variety Jodhpur which was significantly higher than the other varieties, whereas it was minimum (Zero) in Kandhari at the three stages of study. It was observed that the fruits cracked in two patterns, viz diagonal and longitudinal. Cracking that starts from stylar end of fruit and with time extends to equatorial zone was regarded as longitudinal type, whereas the cracking that initiates between the two ends of fruit was diagonal type. Maximum diagonal cracking and longitudinal cracking was observed in variety Ganesh and Jodhpur, respectively. Again no diagonal as well as longitudinal cracking was recorded in Kandhari variety of pomegranate. During fruit growth, fruit weight, size increased significantly at each stage in all the varieties. The fruit juice quality parameters, viz., the juice content, TSS and juice anthocyanin increased significantly at each stage, whereas titratable acidity, juice antioxidants decreased significantly from July to September. The peel characteristics viz., the peel thickness, anthocyanins, cellulase and polygalactouranse activity increased significantly however antioxidants, phenols, peel moisture content continued declining till fruit maturity. Peel moisture percent and peel percent were high in Jodhpur and significantly low in Kandhari. Antioxidant activity in leaf and juice and phenols and peel thickness were higher in Kandhari, whereas activity of polygalactouranase and cellulase were higher in the peel of Jodhpur. The nitrogen, phosphorus and potassium were analyzed in leaf, peel and aril and low level of potassium was observed in Jodhpur in all the tissues, however nitrogen and phosphorus were higher in Jodhpur. There was a significant positive correlation of fruit cracking with physical parameters of the fruits viz., fruit length, breadth, size, weight, aril percent, peel percent, aril/peel ratio; leaf parameters, viz., phosphorus; fruit juice quality parameters, viz., total soluble solids, juice per cent, phosphorus; and peel characteristics viz., peel moisture percent, phosphorus, cellulase and polygalacturonase activity. A negative significant correlation was established between fruit cracking and leaf parameters, viz., antioxidants, proline content, nitrogen and potassium; fruit juice quality parameters, viz., acidity, anthocyanin, potassium and nitrogen; and peel characteristics viz., anthocyanin, peel thickness, total phenols, potassium and nitrogen. SEM examined the peel of Jodhpur and kandhari variety that reveals, the uniform cellular arrangement with no intercellular spaces and rounded cells in peel surface of Kandhari variety make it resistant to cracking while irregular cell arrangement with intercellular spaces and transversely longitudinal cells leads to high cracking in Jodhpur.ThesisItem Restricted Germination efficiency and plant stand in early sown synthetic wheat derived population(Punjab Agricultural University, Ludhiana, 2021) Navdeep Kaur; Bedi, SeemaWheat crop has specific temperature requirements. In Punjab, wheat is generally sown from last week of October till last week of November and harvested after mid-April. The early sown crop has more time to attain maturity and produces higher yield than the late sown crop. However, a shift in sowing dates imposes temperature stress at different crop growth stages. The present study was conducted on synthetic wheat lines derived from Aegilops tauschii × Triticum durum with an aim to identify heat tolerant lines. These lines were evaluated at normal (25°C and 30°C) and high temperatures (35°C) under laboratory conditions and thereafter in field exposed to heat stress by shifting normal sowing date to early and late sowing. The activity of α-amylase was one of the criteria to determine heat stress tolerance at seedling stage. The lines HT8, HT12, HT13 performed well under high temperature stress in both laboratory conditions and in the field. Under laboratory conditions, these lines had maximum α-amylase activity and coleoptile length. In field conditions, these lines had high early growth vigor, yield and thousand grain weight. So, these can be identified as heat stress tolerant lines while HT140 and HT157 neither germinate at high temperature in laboratory nor gave much yield under temperature stress in field and also α-amylase activity was lowest. These lines were regarded as heat susceptible lines. The results of this study may prove useful in the selection of potential donors for heat stress tolerance.ThesisItem Restricted Mitigating heat stress through plant growth regulators in tomato (Solanum lycopersicum L.)(Punjab Agricultural University, Ludhiana, 2021) Bhatia, Jaya; Ghai, NavitaThe present investigation was carried out to study the effect of GA3 and 4-CPA in mitigating heat stress in tomato (Solanum lycopersicum L.). Three cultivars of tomato viz. Punjab Ratta, Punjab Varkha Bahar-4 and LST-6 were selected for the study. Plant growth regulators are known to ameliorate the effects of elevated temperature through improving fruit set% and pollen viability thereby enhancing yield. Foliar application of GA3 (10, 20 and 30µg/ml) was done after three weeks of transplanting and application of 4-CPA (15, 45 and 75 µg/ml) was done at anthesis stage. Observations on morphy-physiological parameters, biochemical parameters and yield attributes were recorded at the interval of 10 days after treatment i.e between 30 to 70 days after transplanting (DAT). Application of GA3 and 4-CPA helped the plant to survive in heat stress by imparting thermo tolerance. Improvement in plant height, leaf area, chlorophyll content, carotenoid content, Hill reaction activity in leaf chloroplasts, total soluble proteins, total phenols, total soluble sugars and starch content was observed in treated plants as compared to controls. GA3 and 4-CPA also increased the cell membrane stability, proline content and lowered the lipid peroxidation in leaves. Along with this enhanced amount of lycopene content, titratable acidity% and total soluble solids were also recorded in tomato fruits. The increase in fruit set% and pollen viability was observed with the application of GA3 and 4-CPA which gradually resulted in increased number of fruits per plant and yield. The application of 75 µg/ml 4-CPA was most effective.ThesisItem Open Access Hybrid purity testing using morphological, physiological, biochemical and molecular markers in maize (Zea mays L.) hybrids(Punjab Agricultural University, Ludhiana, 2021) Damanpreet Kaur; Navjyot KaurThe present investigation entitled „Hybrid purity testing using morphological, physiological, biochemical and molecular markers in maize (Zea mays L.) hybrids‟ was conducted at Seed Physiology Laboratory, Office of Director (Seeds), during 2019-2021. The seeds of maize hybrid PMH1, its female parent (LM13), male parent (LM14); and hybrid PMH 10, its female parent (LM23), male parent (LM24) were procured from Maize Section, Department of Plant Breeding and Genetics, PAU, Ludhiana. DUS (distinctness, uniformity and stability) were recorded by sowing the hybrids PMH 1, PMH 10 and their parents under field conditions and characters were recorded. Eight and seven DUS characters were found to be polymorphic which could distinguish hybrid PMH 1 and PMH 10, respectively, from their parental lines. SVI II of LM 14 was significantly higher than LM 13 and PMH 1. SVI I and SVI II of hybrid PMH 10 and male parent were significantly higher than female parent. SDS-PAGE analysis of hybrid PMH 1 revealed one polymorphic polypeptide band corresponding to polypeptide of 45 kDa in female and 50 kDa in male which can be used for confirming the hybridity of maize hybrid PMH 1; while hybrid PMH 10 did not reveal any polymorphism. Superoxide dismutase and esterase zymography of hybrid PMH 1 revealed polymorphism which can be employed to test PMH 1 hybrid purity; while these two isozymes did not recorded any polymorphic isozymic bands in hybrid PMH 10. Peroxidase zymography of both hybrids PMH 1 and PMH 10 revealed polymorphism which can be employed for testing hybrid purity of both the hybrids. In molecular analysis, out of 200 primers screened, six SSR markers viz., bnlg1036, umc2170, umc2069, bnlg1297, umc1227 and bnlg1754 were found to be polymorphic which had potential to identify hybrid purity of PMH 1. Seven primers viz., umc1627, umc1786, umc1366, phi080, bnlg1297, bnlg1203 and bnlg1036 were polymorphic and capable of identifying PMH 10 hybrid purity
