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ThesisItem Open Access Variability in Ustilaginoidea virens (Cke.) Tak. causing false smut of rice and identification of resistance sources(PAU, 2014) Rani, Ritu; Sharma, Vineet KFalse smut of rice (Ustilaginoidea virens) has become an important disease causing significant yield losses in major rice producing states of India including Punjab. Thirty five isolates of U. virens were differentiated on the basis of their morphological, physiological, pathological and molecular characteristics. All the isolates produced well defined colonies on potato sucrose agar (PSA) medium with colony diameter ranging from 26.0 to 90.0 mm after 2 weeks of incubation. Colony color in most of the isolates was initially white which changed to yellow and finally became green. The conidia were spherical, hyaline and warty and size ranged from 4.05-4.94 to 6.10-6.36μm. The isolates also differed in the growth pattern from appressed, fluffy, less fluffy to raised. Sectoring in mycelial growth was observed in five isolates (Uv25, Uv26, Uv27, Uv28 and Uv29). Mycelial growth of representative isolates (Uv1, Uv4, Uv9, Uv13, Uv21, Uv28) of U. virens grown on Czapek‘s dox agar as basal medium was highly variable when supplemented with different carbon and nitrogen sources with maximum utilization of sucrose and sodium nitrate, respectively; consequently resulting in highest growth. Maximum growth was produced when isolates were incubated at 25 ± 2°C (average dry weight = 57.74mg) followed by 30 ± 2°C (56.84mg). Sucrose (2 and 1%) was found superior in inducing spore germination than dextrose. Potato sucrose broth was the best medium for supporting maximum mycelial growth (104.80mg) and sporulation. Maximum colony diameter and sporulation was also observed on PSA (68.74mm) followed by potato dextrose agar (59.26mm). Maximum sporulation was produced on natural substrate medium based on barley seeds (5.54 X 105 conidia/ ml). Among all the isolates, Uv1 was found more aggressive on both the cultivars. Rest of the isolates varied in their virulence/ aggressiveness behavior on tested cultivars and two isolates viz. Uv17, Uv26 and Uv28 failed to produce disease on PR 114. The genetic variation among 35 isolates of U. virens by PCR amplification using ten random operon decamer primers showed polymorphism. Similarity coefficient values among U. virens isolates ranged from 0.56 to 0.97. Of 31 elite germplasm lines three viz. PAU-3965-11-4-1-4-2, PAU-3965-11-4-1-1-2, PR118 were highly resistant while PR122 and PR114 were resistant. Disease incidence, infected panicle and number of balls/plant were increased with increased nitrogen level on rice cultivars viz. PR114 and PR116.ThesisItem Open Access Identification, characterization and functional analysis of auxin efflux carrier gene TaPIN1 in Wheat(Punjab Agricultural University, Ludhiana, 2014) Kanwardeep SinghPolar auxin transport (PAT) through differentially located influx and efflux carriers’ controls many plant developmental processes. Present study is aimed at characterizing one such auxin efflux carrier gene (PIN1) in wheat using functional and translational genomics. In-silico analysis of the gene revealed the presence of conserved gene structure among monocots and dicots with six exons and five introns. Most divergent first two exons of the gene marked with monocot specific deletions/insertions code for the hydrophobic loop of the PIN1 protein. Intron evolution revealed the presence of conserved intron phases along with three ancient introns, out of which two introns showed intron sliding in some species. The proto-splice sites governed insertion of the first two introns in PIN1 gene emphasizes intron insertion after monocot-dicot divergence. Multiple amino acid sequence alignment ascertained the presence of conserved trans-membrane domains and motifs along with some species specific uncharacterized motifs in the central hydrophobic loop. Presence of the disordered protein region in the central loop and differences in the 3d structure of PIN1 protein highlights diversification of PIN1 gene among monocots and dicots as suggested by their phylogenetic analysis. BSMV-based Virus Induced Gene Silencing resulted in significant reduction of plant height (up to 30%) in wheat plants without effecting other plant traits like leaf elongation, tillering and anthesis etc. Copy number prediction and physical mapping of the PIN1 revealed the presence of atleast four copies on wheat chromosomes 6 and 7.These findings suggest the presence of functional orthologue of PIN1 gene in wheat, which can be further exploited as a candidate gene for alternate dwarfing system.ThesisItem Open Access Epidemiology and management of bacterial blight of pomegranate(Punjab Agricultural University, 2014) Ashish; Arora, anitaBacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae has been observed as a serious impediment in the cultivation of pomegranate in Punjab. The disease initiated in June. Symptoms appeared as small, circular to irregular, water-soaked spots on leaves, flowers and fruits. On fruits, the spots developed into typical cankers with cracks on the necrotic areas. The bacterium produced pale yellow, circular, convex, slightly raised, opaque and mucoid colonies on nutrient agar medium. The bacterial cells were straight rods, Gram-negative and motile. The pathogen successfully established on all the inoculated plant part viz. leaves, flowers, twigs and fruits. Per cent disease index and infection rate were high, when inoculations were carried out in the month of July than in the months of June and August. Weather parameters like mean maximum and minimum atmospheric temperature, relative humidity and rainfall influenced disease progression significantly. None of the strains screened against this disease was found resistant. The strains expressed moderate to highly susceptible reactions. Four sprays of blitox + streptocycline on the pruned plants starting from mid June to end July at 15 days interval proved effective against bacterial blight of pomegranate. Kocide + Streptocycline was the next best treatment in reducing the per cent disease index.ThesisItem Restricted Development of screening technique for false smut of rice(Punjab Agricultural University, Ludhiana, 2014) Yesmin Kaur; Lore, Jagjeet SinghABSTRACT The present study was conducted with objective to develop innovative screening technique for artificial creation of false smut disease under field and greenhouse conditions. Growth and sporulation of Ustilaginoidea virens was studied under in-vitro conditions. The pathogen produced white-fluffy mycelial colony on potato sucrose agar medium. Yellow coloured spore mass of chlamydospores and conidia was observed after 20 days of incubation. Different inoculation methods viz. spray inoculation and dusting of dry spores at early flowering stage and syringe inoculation method using two volumes (1 ml and 2 ml) at boot stage were evaluated on varieties PR116 and PR114. Spray inoculation of spore suspension enhanced intensity of disease variables such as infected panicle and number of smut balls per panicle followed by the syringe inoculation method. However, the later produced more sterility in panicles. Cultured inoculum prepared in-vitro produced more disease infection than the fresh inoculum. Higher disease variables were recorded in plants which were provided with artificial humidity than those grown under natural conditions. High disease severity was observed in late planted crop as compared to timely planted which was positively correlated with weather factors. One hundred twenty-five hybrids were evaluated for resistance to false smut. Six lines along with susceptible check, PR116 showed high disease severity however, ten lines were found free from disease. Rest of the entries showed intermediate disease response.ThesisItem Open Access Relationship of occurrence and development of powdery mildew of wheat with weather parameters and its management(Punjab Agricultural University, Ludhiana, 2014) Sarbpreet Singh; Pannu, P.P.S.Powdery mildew of wheat caused by Blumeria graminis f. sp. tritici is one of the most important diseases worldwide. In India it occurs in certain parts of the North-Western Plains and hill Zone. It occurs regularly in sub mountainous areas of Punjab. Surveys carried out during 2012-13 and 2013-14 revealed that powdery mildew was more severe in the districts of Hoshiarpur, Ropar, SBS Nagar and Gurdaspur. Investigations on relationship of occurrence and development of disease with weather parameters revealed that temperature, relative humidity and rainfall play significant role in the progress of disease. Rate of progress was found to be higher during October and February-March due to the favourable environmental conditions. Investigations on effect of date of sowing (November 1st, November 15th and November 30th) and method of sowing (Flat sowing and Ridge sowing) revealed that severity of disease was lower in the ridge sowing of November 30th sown crop. The experiments on the effect of different seed rates (35, 40, 45 and 50 Kg/acre) on the development of the disease revealed that the severity of the disease was higher in higher seed rate. Out of 329 genotypes screened under the field conditions 118 were found to be susceptible, 28 moderately susceptible, 42 moderately resistant and 141 were highly resistant. The evaluation of fungicides namely Tilt 25 EC (propiconazole), Folicur 25 EC (tebuconazole), Folicur 430 SC (tebuconazole 430 SC), Bayleton 25 WP (triadimefon), Amistar Top 325 SC (azoxystrobin + difenoconazole), Amistar Extra 280 SC (azoxystrobin + cyproconazol), Picoxystrobin + Propiconazole 20 EC, Nativo 75 WG (trifloxystrobin + tebuconazole), Opera 25 SC (pyraclostrobin + epoxiconazole) and Karathane 48 EC (dinocap) were found to be effective against Blumeria graminis f. sp. tritici in-vitro at different concentrations viz. 10ppm, 25ppm, 50ppm, 100ppm and 200ppm using poison food technique in water agar media. These fungicides were also evaluated against the disease under field conditions and were found to check powdery mildew of wheat effectively.ThesisItem Open Access POPULATION DYNAMICS OF Phytophthora nicotianae var. parasitica CAUSING FOOT ROT IN KINNOW MANDARIN(Punjab Agricultural University, 2014) Dhakad, Umesh Kumar; Sarbjeet KaurFoot rot/gummosis of Kinnow mandarin caused by Phytophthora nicotianae var. parasitica causes considerable damage in nursery as well as in established orchards under Punjab conditions. Soil sampling studies revealed that pathogen propagules were present throughout the year in orchards. Among the three locations sampled viz. Fazilka, Hoshiarpur and Ludhiana, the maximum number of propagules were present in July (366 propagules/cc of soil) and minimum number of propagules were found in June (8 propagules/cc of soil). Population reached maximum in July and afterwards decreased linearly up to June and reached minimum. Maximum population were found in Hoshiarpur followed by Ludhiana and Fazilka. The pathogen population and feeder root rot were significantly higher in 10 year old Kinnow mandarin plants compared to 5 year old plants. Cultivar viz. Kinnow mandarin and Sweet orange had no significant difference on pathogen population and feeder root rot. Irrigation methods had significant effect on pathogen population. Flood irrigated Kinnow orchards have higher propagules counts as well as higher root rot followed by basin and drip irrigation. Among rootstocks tested against pathogen Citrumelo, Pectinifera and X639 showed tolerant reaction while Cleopatra and Rough lemon found to be most susceptible. Various fungicides were evaluated under in vitro conditions against pathogen. Ridomil Gold MZ exhibited 100 per cent growth inhibition at 10 μg/ml concentration. Melody Duo, Mandipropamid, Fluopicolide and Curzate M8 showed 100 per cent growth inhibition at 50 μg/ml concentrationThesisItem Open Access Population dynamics and pathogenic behaviour of Rhizoctonia solani Kühn in response to rice based cropping system of Punjab(Punjab Agricultural University, 2014) Kipsumbai, Pixley Kiptui; Sekhon, P.S.Present investigations were undertaken to study the R. solani population dynamics and pathogenic behaviour under different crop rotations, AG groups and the extent of genetic differentiation and host specialization between infecting populations in different hosts. By using species specific primers the occurrence of Rhizoctonia species was analysed and were identified as R. solani (87.8 %), 11.1% were R. oryzae-sativae and 1.1 % R. oryzae admixed infection with R. oryzae-sativae. Rhizoctonia solani was characterized morphologically as well as at molecular level, which showed presence of high degree of variation among these R. solani isolates. The R. solani isolates were further grouped into anastomosis groups (AGs) by AG subgroups specific primers and it was established that most potato isolates were AG3 and AG2-1. Rice and maize isolates were mostly grouped into subgroup AG1-1A. R. solani rice isolates were studied for their aggressiveness on six rice genotypes and the aggressiveness response of these isolates were further analysed by Mahalanobis D2 analysis and two major groups were observed. Out of all the R. solani isolates, nearly 20% were found to be highly aggressive. Cross infectivity studies revealed that R. solani isolates were cross pathogenic to other hosts except potato and cotton isolates which were not able to cause any disease symptoms on rice. But R. solani isolates were found to be more virulent on their host of origin than any other host under test except in chilli isolate (Cl-40) was found to be highly adaptive to all hosts. Three cropping patterns and 17 R. solani isolates were tested to study the pathogenic behaviour and population dynamics of R. solani isolates under fixed sick plots. A significant interaction was observed between the R. solani isolates and the crops grown in these three adopted cropping systems. The least population build–up after two years of rotation was recorded in the potato-spring maize-Basmati rice cropping system. The overall mean of rice isolates in this system was 44.7 CFU/g of soil, while it was high in the cropping pattern comprising potato –moong bean-rice and wheat ie. 68.1 CFU/g of soil. To find out development of resistance, eighty five out of total 99 isolates under test showed sensitive reaction to propiconazole below 50 ppm concentration in vitro. Only ten isolates showed growth inhibition at 100 ppm and four R. solani isolates were least responsive and showed growth inhibition at 250 ppm concentration. All the isolates were found to be sensitive in their reaction to pencycuron when compared with Tilt 25EC. The ED90 values for most of the insensitive R. solani isolates were found to be in the range of 14 to 26 ppm for pencycuron and 10 to 78 for propiconazole. These preliminary studies indicated that there is development of fungicide resistance in R. solani rice sheath blight isolates as only partial disease control at 0.1% spray concentration of Tilt 25EC was recorded. As no fungicide is recommended for seed treatment in wheat so the two fungicides namely propiconazole and pencycuron were tried and found effective in controlling seed rot and seedling mortality in R. solani sick pots. At the molecular level using interspecific sequence repeat primers, a total number of 79 R. solani isolates were analysed and were divided into three major groups (I, II, III). There was partial relationship observed between the level of aggressiveness of the isolates on rice and phylogenetic groups generated by the ISSR markersThesisItem Open Access Survival, detection and management of Cucumber Mosaic Virus (CMV) And Zucchini Yellow Mosaic Virus (ZYMV) infecting cucurbits in Punjab(Punjab Agricultural University, Ludhiana, 2014) Sharma, Shikha; Kang, S. S.Cucurbits are known to be affected by many viruses, among them aphid transmitted +ssRNA viruses viz. potyviruses and cucumoviruses of family potyviridae and bromoviridae, respectively are considered most destructive viruses in terms of severe yield loss, causing mosaic, blistering kind of symptoms. In the present study detection of Cucumber mosaic virus and Zucchini yellow mosaic virus was done from major cucurbits grown at vegetable research farm PAU, Ludhiana. A total of 54 genotypes were screened under natural and artificial conditions. Typical mild to severe mosaic, pronounced blistering kind of symptoms were observed in susceptible check ‘Punjab Sunehari’ after one week of sap inoculation. Three lines viz. MM 4021, SM MC 20, MM 4078 were found resistant against CMV and ZYMV infection. Resistant lines were confirmed for absence of virus titre using DAS-ELISA. Variable symptoms resembling leaf deformation accompanied with yellowing and mild blistering were found in mixed infection of Tomato leaf curl virus New Delhi strain with ZYMV from bittergourd. Cucumber mosaic virus subgroup IB, Zucchini yellow mosaic virus, Papaya ring spot virus-P were characterized from cucurbits in Punjab. Role of potato is confirmed in harbouring all the viruses associated with cucurbits viz. CMV subgroup IB, ZYMV as well as Papaya ring spot virus-P. Aphids associated with cucurbits and potato were identified as belonging to species Aphis gosypii and Myzus persicae. These findings confirmed the role of survival of CMV and ZYMV through potato and possible transmission of both the viruses from one crop to the other during the harvesting of potato and sowing of cucurbits in Punjab.ThesisItem Open Access Biology of tetranychus urticae koch and seasonal incidence of mites infesting citrus(Punjab Agricultural University, Ludhiana, 2014) Navjot Kaur; Bhullar, Manmeet BrarThe biology of two-spotted spider mite, Tetranychus urticae Koch and seasonal incidence of mites infesting citrus was studied during 2013-2014 at the Acarology Laboratory, Entomological Research Farm, Department of Entomology and New Orchard, Department of Fruit Science, Punjab Agricultural University, Ludhiana. Biological studies on T. urticae revealed that the mean incubation, larval, protonymphal and deutonymphal period was found to be 2.52, 2.74, 2.08, and 2.40 days, respectively. The pre-oviposition, oviposition and post-ovipostion period was 0.96, 1.78 and 6.40 days, respectively. The fecundity of 1.56 eggs/female and longevity of females (9.40 days) and males (6.71 days) was observed. The sex ratio was in favour of females (4.33:1). Studies on oviposition response of T. urticae on different citrus genotypes revealed that oviposition was found to be maximum on SL-4 and G-4 followed by BL-2 and G-4 genotypes and no egg laying was observed on SL-3, SL-7, G-7, BL-1, BL-3 and Tahiti lime. Feeding preference studies revealed that mites preferred KL-7 genotype the most, but had least preference for G-4 genotype. Observations on the seasonal incidence revealed that peak occurrence of Brevipalpus phoenicis was reported during 47th standard week (SW) (23.0 mites/leaf); Tetranychus urticae during 21st SW (6.25 mites/leaf), while Polyphagotarsonemus latus started occurring during November-December (47th to 25th SW). The population of Eutetranychus orientalis was observed during April-June (16th to 26th SW) as with increase in temperature there was increase in population of mites. The population of predatory mites viz. Tydeids, Phytoseiids and Cunaxids was observed throughout the year with peak incidence during 29th SW and 46th SW, respectively. Although the mite populations showed both negative and positive correlations with the various abiotic parameters, but statistically these were found to be non significant.