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20224
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Author: Navneet Kaur × End date: 2023 × Start date: 2021 × Type: Thesis ×
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    Biochemical evaluation of bitter gourd genotypes in response to yellow mosaic virus disease
    (Punjab Agricultural University, Ludhiana, 2022) Navneet Kaur; Sangha, Manjeet Kaur
    The study evaluated biochemical changes in resistant and susceptible bitter gourd plants; 4 cultivars and 11 advanced lines inoculated with viruliferous whiteflies for about 2 weeks for study of yellow mosaic virus disease (YMVD) caused by yellow mosaic virus (YMV). The disease severity was scored at 15, 30, 45, and 60 days of inoculation (DOI) and grouped the plants into highly resistant (Jhaar Karela, Punjab-15, and Punjab Kareli-1), resistant (PAUBG-407, PAUBG-200, and PAUBG-1514), moderately resistant (PAUBG-204), highly susceptible (Punjab-14, PAUBG-301, PAUBG-229, and PAUBG-341), susceptible (PAUBG128) and moderately susceptible (PAUBG-394, PAUBG-226, and PAUBG-353) groups. Further, PCR diagnosis indicated the presence of the virus in all samples. The infection decreased mean chlorophyll (a, b, total), carotenoids, and Fv/Fm ratio more in susceptible genotypes than resistant genotypes over healthy controls. The susceptible genotypes registered higher total carbohydrates and total soluble sugars but the contents of total soluble and crude proteins decreased with increasing DOI. The infection increased phenols, hydrogen peroxide, catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), phenyl ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD) activity more in infected resistant genotypes than in susceptible genotypes. Data was significant (5%) w.r.t genotypes, stages, and treatments. A greater increase in biochemicals in resistant samples may give better protection and the resistant genotypes may aid in crop improvement programs against YMVD.
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    ThesisItemEmbargo
    Evaluation of edible coatings for microbiological and physicochemical quality maintenance of freshcut carrot and cucumber
    (Punjab Agricultural University, Ludhiana, 2022) Navneet Kaur; Pooja
    Six different edible coatings including chitosan, pectin, alginate, starch, carrageenan and CMC were evaluated to determine their effect on physicochemical properties and microbial growth inhibition over fresh cut cucumber and carrot. Microbial load over FCV was reduced by 1.03 log cfu/g total plate count, 0.49 log cfu/g yeast and mould, 0.61 log cfu/g coliforms count whereas microbial count over fresh cut carrot got reduced by 0.94 log cfu/g total plate count, 0.54 log cfu/g yeast and mould and 0.73 log cfu/g coliforms after disinfecting fresh cut cucumber and carrot with 100 ppm sodium hypochlorite solution for 23 minutes and 8 minutes at 10°C, respectively. After disinfection pretreatment, fresh cut vegetables were coated with above mentioned edible coatings. Evaluation of coatings showed chitosan and pectin showed comparable effects in restricting the microbial growth over fresh cut cucumber. However, chitosan coated FCV exhibited minimum microbial load over FCV after 9 days of storage as compared to other coatings and control FCV samples with maintaining all other quality attributes. Therefore, chitosan was selected for further optimization studies w.r.t coating concentration and dipping time that was statistically designed and analyzed using response surface methodology. Microbial analysis for TPC, Y&M and coliform count and physicochemical analysis viz. pH, TSS, total sugars, and firmness was taken. Fresh cut cucumber dipped in 1 percent (w/v) for 5 minutes and fresh cut carrot dipped in 1 percent (w/v) for 3 minutes was found to be optimum coating conditions, respectively. The validation investigations carried out at 3 kg scale resulted in firmness 4.5 and 24 (lb), total sugars 3.7 and 6.8 (g/100g), TSS 5.2 and 8.0 (ºB), pH 5.0 and 6.5, TPC 4.0 and 3.9 (log cfu/g) ,Y&M 2.0 and 1.8 (log cfu/g) and Coliforms 2.1 and 2.0 (log cfu/g) in fresh cut cucumber and carrot with desirability of 90 percent and 93 percent, respectively. Shelf life studies of pretreated chitosancoated fresh cut cucumber and carrot FCV cucumber and carrot were tested for a period of 12 days or till deterioration at a regular interval of 3 days under optimal coating conditions. Results revealed that chitosan coated FC cucumber and carrot can be consumed upto 12 days and 15 days, respectively while maintaining their desirable physicochemical and sensory characteristics with microbial loads under acceptable range. Microbial count over chitosan coated FC cucumber on 12th day of storage showed 4.54 log cfu/g TPC, 2.90 log cfu/g Y&M and 2.95 log cfu/g Coliforms under acceptable limits while uncoated samples had microbial count above acceptable limits on 6th day of storage. Microbial count over chitosan coated FC carrot on 15th day of storage showed 4.72 log cfu/g TPC, 2.90 log cfu/g Y&M and 2.95 log cfu/g coliforms under acceptable limits while uncoated samples had microbial count above acceptable limits on 6th day of storage. As a result, the present study found that preteated fresh cut cucumber coated with 1 percent (w/v) chitosan for 5 minutes and fresh cut carrot coated with 1 percent (w/v) chitosan for 3 minutes were able to inhibit the microbial load over FC cucumber and carrot during storage period under refrigeration conditions of 5-7º C maintaining its all physicochemical and sensorial characteristics.
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    ThesisItemRestricted
    Effect of harvest stages on fermentation characteristics and nutritional quality of silage in oat genotypes
    (Punjab Agricultural University, Ludhiana, 2022) Navneet Kaur; Goyal, Meenakshi
    The present investigation was aimed at studying the effect of different harvest stages on fermentation characteristics and nutritional quality of silage in oat genotypes. During 2019-20 fifty oat germplasm was screened for nutritional composition viz. crude protein (CP), water soluble carbohydrates (WSC), dry matter (DM), in vitro dry matter digestibility (IVDMD) and field parameters at milk developmental stage to find out the best genotypes for silage making. The average content of CP, IVDMD, WSC and DM was found to be 6.88%, 27.67 mg/g, 51.71% 16.12 % respectively. Principal components (PC 1 & PC 2) cumulatively accounted for 41.5% of the total variation present among the genotypes. The dendrogram constructed using cluster analysis classified the test genotypes into six diverse clusters. Based on the results obtained by above parameters, PCA and cluster analysis, four genotypes (OL 1990, OL 1994, OL 1954 and OL 1968) were selected for silage potential at different harvest stages (heading, milk, dough and maturity stages). During rabi 2020-2021 above four genotypes along with three checks (OL 12, OL 13, OL 1861) were raised in the field of Forages, Millet and Nutrition section, Dept. of Plant Breeding and Genetics. At the respective harvest stages, silage was prepared in five kg polythene bags. At these stages forage sample was also taken for nutritional analysis. Fodder samples were analysed for nutritional composition, IVDMD and yield parameters. The quality attributes CP, IVDMD, WSC decreased and DM, acid detergent fiber (ADF), neutral detergent fiber (NDF) and acid detergent lignin (ADL) increased with advancing maturity of vegetative fractions of plant. The silage was opened after 45 days, analysed for fermentation characteristics, nutritional composition, IVDMD. ADF, NDF, DW and ADL increased with increase in maturity stages. The highest content of lactic acid and volatile fatty acids was found in OL 12 and OL 1896. Optimum pH was observed in dough stage of silage. Genotypes OL 1990 and OL 1861 had shown maximum values of WSC and IVDMD at dough stage. Overall, in the present study, silage prepared from dough stage had better yield and fermentation characteristics and proves to be the best stage for silage making due to appropriate dry matter and pH. Also, OL 1861, OL 1990 and OL 12 genotypes responded better in terms of quality traits as well as yield of the crop.
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    ThesisItemOpen Access
    Conversion of non-aromatic rice to aromatic rice by editing Betaine Aldehyde Dehydrogenase (BADH2) gene
    (Punjab Agricultural University, Ludhiana, 2022) Navneet Kaur; Vikal, Yogesh
    Aroma in rice is a highly appreciated trait and acts as determining factor for market price. Basmati rice varieties possess characteristic aroma, however, are usually low yielding. Attempts for transfer of aroma to high-yielding rice varieties through conventional breeding approaches have not been much successful. CRISPR/Cas9 technology has been established as a revolutionary crop improvement technique. The ribonucleoprotein (RNP) mediated delivery of the CRISPR/Cas9 complex is showing immense potential for transgene-free genome editing in rice. The current research was carried out for editing of OsBADH2 gene through CRISPR/Cas9-RNP complex in PR114, high yielding non-aromatic rice variety. A total of five gRNAs were designed through CRISPR P 2.0 for generation of OsBADH2 mutants. Primers were designed for the assembly of gRNA-DNA template for two gRNA selected and transcribed to gRNA utilizing “GeneArtTM Precision gRNA synthesis Kit”. The cleavage efficiency of RNP complex was detected through in vitro cleavage detection. The gRNA were incubated with Cas9 nuclease enzyme to form RNP complexes and coated onto gold particles for the biolistic delivery into the explants. Embryos excised from mature seeds and calli were used as explants for transformation. A variety of media were tested for callus induction and regeneration in PR114. Approximately, 2000 mature embryos and 381 calli were transformed using gRNA-Cas9 complex delivered through gene gun. A total of 35 plants, created through transformation of gRNA-RNP complex targeting exon 7, were characterized through MSBSPPCR technique. The plants showing positive results were proceeded for Sanger’s sequencing. The sequencing results were analysed through FinchTV software for quality of sequencing. The sequences were aligned using Clustal Omega and NCBI-BLASTn online tools. An addition of nucleotide “A” was found in one plant. The nucleotide sequence was translated through Expasy tool. Through insilico analysis of the amino-acid sequence of mutant frameshift mutation was observed. The mutation resulted in alteration in the last four aminoacids of the peptide chain. The T1 progeny of this mutant plant didn’t show presence of the mutation. Rest of the transformed T0 plants are being screened through restriction digestion assay. The mutants so found will be further analyzed through molecular and biochemical techniques