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ThesisItem Open Access Studies on pathology of Escherichia coli infection in bovine calves and exploration of in vitro antimicrobial potential of certain plant extracts(CSK HPKV, Palampur, 2022-12-17) Priyanka; Patil, R.D.The present study was conducted to determine the pathology caused by Escherichia coli infection in bovine calves in Himachal Pradesh. A total of 222 fecal samples were collected from dead, clinically sick and apparently healthy calves upto one year of age. Necropsy examination of 30 calves upto one year of age including 24 males and 6 females was done during the time period of 1 June, 2021 to 30 June, 2022. Grossly, enteritis was present in 26 (86.67%) calves, ulcerative abomasitis in 5 cases (16.67%), diptheretic enteritis in 1 case (3.33%), milk rumenitis in 1 case (3.33%), nodular abomasitis in 1 case (3.33%) and haemorrhagic typhlitis in 1 (3.33%) case. Histopathologically, vascular changes (congestion, edema, haemorrhages etc.), villous denudation and sloughing, cryptal necrosis, hyperplastic activity of enterocytes, increased goblet cell activity and infiltration of inflammatory cells were the consistent findings. Along with this, macroshizonts and microschizonts of coccidia in tips of villi, bacterial colonies, depletion of lymphocytic element from Peyer’s patches and proliferation of fibrous connective tissue in Peyer’s patches were also found. E. coli was found to be the major cause for gastrointestinal pathologies (55.78%) and responsible for deaths among calves. The prevalence of E. coli in Himachal Pradesh was found to be 47.75% out of which pathogenic E. coli contributed to 40.1%. Molecular pathotyping revealed that enteropathogenic E. coli (EPEC) was present in 57/222 (25.67%) samples, enterohaemorrhagic E. coli (EHEC) was 31/222 (13.96%), enterotoxigenic E. coli (ETEC) was 28/222 (12.61%) and enteroaggregative E. coli (EAEC) was present in 80/222 (36.04%) fecal samples. 25 different serotypes of all the 106 E. coli isolates were identified with serotype O119 (12.26%) being most common followed by O98 (10.38%) and O126 (9.43%). CST for 106 isolates of E. coli against 16 commonly used antibiotics revealed that highest resistance was shown by Cloxacillin (58.49%) followed by Furazolidone (53.77%). 21 E. coli isolates were found to be resistant against one antibiotic group, 17 were resistant against two antibiotic groups, 26 were found to show resistance against three antibiotic groups and rest 42 samples were resistant to more than three antibiotic groups. Upon screening of 15 plant extracts (50% aqua- alcoholic) for their antimicrobial potential against 6 serotypes of multidrug resistant (MDR)-E.coli, five plant extracts i.e. Artemisia nilagirica (C.B. Clarke) Pamp., Asparagus adscendens Roxb., Phyllanthus urinaria, Physalis peruviana Linn. and Tinospora cordifolia were found to have zones of inhibition of varying diameters at different concentrations. In conclusion, the present study revealed that E. coli infection leading to enteritis was the major cause of death in bovine calves upto 1 year of age in Himachal Pradesh. The plant extracts seem to be future alternative to counteract the antimicrobial resistance in animals and humans.ThesisItem Open Access Effect of long-term application of fertilizers and amendments on soil physical quality and crop productivity in an acid Alfisol(Palampur, 2022-12-05) Priyanka; Sankhyan, Narender K.The present investigation was carried out in an on-going long-term fertilizer experiment, initiated during 1972 at experimental farm of Department of Soil Science, CSK HPKV Palampur, to study the effect of long-term application of fertilizers and amendments on soil physical quality and crop productivity in an acid Alfisol under maize-wheat cropping system. The experiment consisted of eleven treatments. The soil of the experimental site was silt loam and classified taxonomically as “Typic Hapludalf” (Subgroup). Soil samples, collected from two depths viz., 0-0.15 and 0.15-0.30 m after the harvest of maize (kharif 2021), were analyzed for determination of different physical parameters (bulk density, particle density, porosity, water holding capacity, water stable aggregates, mean weight diameter, saturated hydraulic conductivity, atterberg’s limits and infiltration rate), chemical parameters (CEC and SOC). Application of inorganic fertilizers along with FYM decreased the bulk density and increased the porosity, WHC, WSA, MWD, SHC, atterberg’s limit and infiltration rate over control. Thus, these properties showed improvement in FYM amended plots than unfertilized control plots. Grain and stover samples were also collected and analyzed to calculate nutrient uptake. Continuous application of fertilizers and amendments for forty-nine years significantly influenced the nutrient uptake and yield of maize. The treatment comprising 100 per cent NPK + FYM recorded the highest grain (64.02 q ha-1 ) and stover yield (103.21 q ha-1 ) and nutrient uptake and was at par with 100 per cent NPK + lime. Omission of S and K decreased the grain yield by 63.4 and 61.4 per cent, respectively over 100 per cent NPK, whereas, continuous application of N alone resulted in zero yield. Addition of manure or lime along with recommended dose of fertilizers improved the soil health in terms of physical and chemical properties of soil. Different soil physical properties were significantly and positively correlated with nutrient uptake and grain and stover yield of maize except bulk density which was negatively correlated.ThesisItem Open Access GENETIC STUDIES FOR YIELD TRAITS AND POWDERY MILDEW RESISTANCE IN DUAL PURPOSE OAT (AVENA SATIVA L..) GERMPLASM.(CSKHPKV, Palampur, 2019-07) Priyanka; Sood, V.K.The present investigation entitled “Genetic studies for yield traits and powdery mildew resistance in dual purpose oat (Avena sativa L.) germplasm” was undertaken to understand the nature of variation and associations among different agro-morphological and quality traits with yield and to identify powdery mildew resistant dual purpose oat genotypes. The experimental material consisting of 55 genotypes along with 3 checks of oat were raised in Randomized Block Design with three replications during Rabi 2018-2019 and data were recorded separately for dual purpose traits and sole seed yield related traits Genetic diversity among different genotypes was studied on the basiis of morphological traits using Mahalanobis D2-statistic and PCA. Screening of genotypes for powdery mildew resistance was done under in vivo and in vitro conditions and further, confirmed through molecular markers tightly linked to pm resistant gene. Mean values for different traits revealed that seven genotypes viz., OATS-80, HJ-8, KRRAK- 26, JPO-28, JPO-38, IG-03-205 and EC-528883 were found superior for green fodder yield per plant as well as seed yield per plant i.e. for dual purpose; out of which, JPO-28, JPO-38, IG-03-205, EC-528883 and HJ-8 also found superior for β-glucan, ADF and NDF content, while, genotypes JPO- 28, JPO-38, IG-03-205 and KRR-AK-26 were found resistant to powdery mildew. PCV along with GCV were high for tillers per plant, dry matter yield per plant, crude protein yield per plant and biological yield per plant, whereas, for β-glucan content, moderate PCV with low GCV was observed ,while, for regeneration percent low PCV with low GCV was observed. High heritability along with high genetic advance was observed for tillers per plant, dry matter yield per plant and crude protein yield per plant. Path coefficient analysis revealed the high direct effect of dry matter yield per plant, dry matter percent, days to 50 % flowering and tillers per plant for fresh fodder yield; whereas, for seed yield high direct effect of days to 75% maturity, tillers per plant, biological yield per plant and harvest index was observed. Therefore, these would be the best selection indices to select high yielding dual purpose genotypes. Based on D2-statistic, genotypes were grouped into 12 clusters in case of dual purpose traits whereas in case of seed yield related traits genotypes were grouped into 11 clusters. Three genotypes viz., IG-03-205, EC-528883 and OS-6 were found to be diverse for both dual purpose as well as seed yield related traits and can be utilized in future hybridization programmes. Eight genotypes viz., JPO-28, OS-6, PLP-1, JPO-46, JPO-36, KRR-AK-26, JPO-38, and IG-03-205 were found resistant to powdery mildew under in vivo as well as under in vitro conditions and confirmed through molecular marker AM-102 that is tightly linked tto pm resistant gene Eg-5. Overall, on the basis of mean values, genotypes namely, EC-528883, JPO-28, JPO-38, HJ-8 and IG-03-205 were found superior for dual purpose (fodder yield as well as seed yield), β-glucan content and contained a lower concentration of ADF and NDF content. Out of these, JPO-28, JPO-38, and IG-03-205 were found resistant to powdery mildew. So, these genotypes can be further tested over years and locations.
