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ThesisItem Restricted Management Of Sclerotinia Stem Rot Of Rapeseed-Mustard Incited By Sclerotinia Sclerotiorum (Lib.) De Bary(Punjab Agricultural University, 2023) Yadav, Monika; Sandhu, P.S.Sclerotinia stem rot caused by Sclerotinia sclerotiorum, is an important fungal disease of rapeseed and mustard crop because of its destructive nature. In the present study, 112 genotypes of rapeseed-mustard screened against stem rot disease. Ten genotypes (EC223400, EC765482, IC268306, IC296703, IC491169, IC491178, IC491197, IC491290, IC531377 and IC538699) were found moderately resistant to the pathogen. Early sowing of brassica during first week of October results in lower incidence of the disease and higher yield compare to the late sowings. Poison food technique was used to evaluate botanicals and fungicides under in vitro condition. Among the botanicals maximum per cent inhibition in mycelial growth was observed in case of Chenopodium album at 20 per cent concentration. Whereas, in case of fungicides complete inhibition (100%) was observed in combination fungicides picoxystrobin 7.05%+ propiconazole 11.7% w/w SC, azoxystrobin18.2% w/w + difenoconazole 11.4% w/w SC and fluopyrum 17.7% w/w + tebuconazole 17.7% w/w SC at a concentration of 5, 10 and 25 ppm, respectively. Under in vitro conditions, combination fungicides were more effective against S. sclerotiorum compared to contact fungicide mancozeb 75 % WP which resulted in lower inhibition of pathogen growth even at higher concentrations. The same set of botanicals and fungicides were used under in vivo conditions as a foliar spray application. Chenopodium album at 40 % concentration was observed most effective in reducing the per cent lesion length as compared to the control. Combination fungicide picoxystrobin7.05%+ propiconazole 11.7% w/w SC resulted in lower lesion length development and highest yield as compare to the control in Brassica juncea var. RLC 3.ThesisItem Restricted Sheath rot and its association with discolouration of rice(Punjab Agricultural University, Ludhiana, 2021) Sarbjit Kaur; Anju BalaThe present investigation was undertaken with the objective to find out the association of pathogens causing grain discolouration and sheath rot of rice and to identify the resistance sources against sheath rot in rice germplasm. Four pathogens viz., Sarocladium oryzae, Fusarium verticillioides, Fusarium fujikuroi and Albifimbria terrestris were found associated with sheath rot and grain discoloration of rice. The fungal pathogens were inoculated on plants using syringe inoculation, grain insertion method and spray inoculation on 2 varieties, PR 114 and PR 121. The variety PR 114 was more susceptible to fungal disease as compared to PR 121. Plants inoculated with grain insertion method showed high disease incidence followed by syringe inoculation method. Among all the pathogens, S. oryzae caused maximum per cent disease incidence and severity followed by F. verticillioides, F. fujikuroi and A. terrestris. The highest disease progress was also observed in plants inoculated with S. oryzae. All the pathogens produced similar disease symptoms in rice. All the pathogens caused chaffiness of panicles, significant reduction in seed germination, seedling length and vigor index was observed in highly infected seeds. The seed quality deterioration was directly proportional to the intensity of seed infection. Further, the effect of fungal metabolites extracted from discoloured grains was observed on physiological and biochemical parameters by dipping seeds in these metabolites for different durations. The seed quality losses were increased with the increase in duration of seed dipping in fungal metabolites. Significant reduction in total sugars and total proteins along with an increase in defense related enzymes, amino acids, proline, total phenols and malondialdehyde content was recorded. Fifty advanced breeding lines of promising rice germplasm were screened against sheath rot by inoculating three pathogens S. oryzae, F. verticillioides and F. fujikuroi using two inoculation techniques (syringe inoculation and grain insertion). Among all the lines evaluated against sheath rot, RYT 3886 was found to be resistant and RYT 3836 was moderately resistant to all the three pathogens.ThesisItem Embargo Biodiversity of seed-borne pathogenic mycoflora of wheat (Triticum aestivum L.) in Punjab(Punjab Agricultural University, 2023) Rubleen Kaur; Tak, Parminder SinghA total 105 grain markets of 23 districts of Punjab were surveyed for study of seed-borne mycoflora during 2021-22 and 654 grain samples were collected. Grains were visually inspected for incidence of Karnal bunt (KB), Black point (BP) and shrivelling. Prevalence of Karnal bunt, Black point and shrivelled grains was 10.24%, 55.20% and 79.51 per cent, respectively. Grain samples from Patiala and Mansa were found to have statistically lowest KB, black point and shrivelled seeds while highest incidence was observed in Pathankot followed by Hoshiarpur and Mohali. Three pathogenic and nine opportunistic fungi were isolated from these samples. Fungal diversity in Sarhali Kalan samples (66.67%) was highest, followed by Sirhind-1, Jalandhar, Rajpura (58.3% each). Bikhi, Nabha, Dadehra, Bucho mandi, Panjgrain (16.67%) carried low mycoflora load. All the samples collected met the minimum seed certification standards for germination. Maximum vigour index I and II of 3327.6 and 26.46 was observed in grain samples collected from Doraha-1 and Shahkot, respectively. Prevalence of Alternaria spp. (94%) was highest followed by Fusarium spp. (64%), Aspergillus flavus (48%) whereas, low prevalence was observed for Exserohilum sp. and Leohumicola sp. (2% each). The fungal isolates were characterized on the basis of morphology and cultural characteristics into 11 fungal genera belonging to 7 families which included Alternaria alternata, Bipolaris sorokiniana, Curvularia verrucosa, Curvularia spicifera and Exserohilum rostratum from Pleosporaceae family (34%); Aspergillus flavus, A. japonicus and Penicillium digitatum, from Aspergillaceae (17%); Fusarium equiseti from Nectriaceae (8%); Epicoccum purpurascens from Didymellaceae (8%); Leohumicola sp. from Incertae sedis (8%), Chaetomium globosum and Pseudothielavia terricola from Chaetomiaceae (17%) and Rhizopus stolonifer from Rhizopodiaceae (8%). Sequencing of Curvularia verrucosa, Bipolaris sorokiniana, Curvularia spicifera, Aspergillus japonicus, Pseudothielavia terricola, Alternaria alternata and Fusarium equiseti was done and cultures have been deposited in MTCC repository, Chandigarh. Thirty nine fungal isolates were inoculated on three wheat varieties and determined for seed health, foliar blights and carryover studies. Opportunistic fungi such as Curvularia sp. (isolate CUS-1), Aspergillus sp. (isolates AF-1, AF-7), Rhizopus sp. (RIZO-1), Penicillium sp. were found to reduce germination under field conditions. Highest average foliar blight severity was observed in Gurdaspur (26.98%) as compared to 20.60 per cent in Ludhiana. Bipolaris isolate BIS-1, Aspergillus flavus AF-1, Curvularia CUT-1, Alternaria ALT-6 and ALT-10 resulted high severity in Ludhiana while Fusarium FUS-1, Rhizopus RIZO-1, Drechslera DRH-3, Aspergillus flavus AF-7 and Alternaria ALT-8 were highly pathogenic in Gurdaspur. The seed inoculated with these fungi induced foliar blight, affected the germination as well as severity of foliar blight however, they could not be re-isolated in all the cases indicating their primary role only up to seedling stage. Overall, Alternaria spp. had the highest frequency in grain market samples as well as carryover studies.ThesisItem Restricted Epidemiology and Management of Post harvest diseases of Kinnow mandarin(Punjab Agricultural University, Ludhiana, 2021) Gurwinder Kaur; Raheja, SandeepSurveys were conducted periodically (twice in a month) from January to March during 2019 and 2020 to record the incidence and prevalence of major post-harvest rots of Kinnow mandarin and pathogens associated with it in South-western Punjab. Highest incidence of post-harvest rot of Kinnow mandarin 20.21 and 12.59 percent was observed in the month of March during the year 2019 and 2020, respectively. Penicillium digitatum and Penicillium italicum causing green and blue mould rots were found to be two most prevalent post-harvest pathogens with their prevalence of 30.88 and 26.44 percent, respectively during 2019 and 32.44 and 24.88 percent, respectively, during 2020. Temperature of 25˚C favoured maximum radial growth (84.67 mm) of both test pathogens also, maximum percent disease index of green (95.00 percent) and blue mould rot (90.00 percent) was recorded at 25˚C. The pH 5.5 and 6.0 supported maximum radial growth of P. italicum by 90.00 & 88.66 mm and of P. digitatum by 88.67 & 87.67 mm, respectively and were found to be at par with each other. Among different GRAS chemicals and botanicals evaluated against test pathogens, copper sulphate, boric acid, sodium bicarbonate and sodium carbonate at 100mM and above concentrations among chemicals and garlic extract at 10 per cent and above concentration among botanicals showed complete inhibition (100.0 percent) of both test pathogens under in vitro, whereas, under in vivo garlic extract at the concentration of 15 percent showed complete inhibition of green (100.0 percent) and of blue mold rot (92.22 percent). Boric acid at the concentration of 4 percent showed complete inhibition (100.0 percent) of both the test pathogens.ThesisItem Embargo Diversity of betasatellites associated with legumovirus(es) and their role in disease severity of yellow mosaic disease in mungbean(Punjab Agricultural University, 2023) Patil Amit Shantaram; Sirari, AsmitaA set of 69 Yellow Mosaic Disease (YMD) infected samples of different cultivars of mungbean and urdbean were investigated from different locations. Out of 69 samples, 45 showed mixed infection of Mungbean yellow mosaic virus (MYMV) and Mungbean yellow mosaic India virus (MYMIV). However, YMD infected samples showing leaf curling, puckering, total yellowing and leaf crumpling symptoms showed presence of betasatellites in 8 samples whereas presence of alphasatellites was shown in 5 samples. Furthermore, 10 whitefly samples were collected from mungbean and urdbean ecosystem for assessing presence of legumovirus-satellite complex. All whitefly samples showed presence of MYMV, MYMIV, betasatellites and alphasatellites. Eighteen off season monocot and dicot weed species were assessed for presence of Legumoviruses-satellite complex, out of which 17 weeds showed presence of MYMV only. After characterization of these detected strains, it was observed that Digera arvensis yellow vein betasatellite associated with MYMV and MYMIV was infecting mungbean. Furthermore, Radish leaf curl betasatellite, Potato apical leaf curl disease associated betasatellite, Digera arvensis yellow vein betasatellite and Tobacco leaf curl betasatellite along with Ageratum yellow vein India alphasatellite and Ageratum enation alphasatellite were found to be infecting urdbean. The diverse helper begomoviruses were observed in mungbean and urdbean namely MYMV, MYMIV, Radish leaf curl virus and Senna leaf curl virus. The whitefly vector collected from mungbean and urdbean ecosystem was found to acquire Rhynchosia yellow mosaic betasatellite, Papaya leaf curl betasatellite and radish leaf curl betasatellite along with Cajanus leaf curl Delhi alphasatellite, papaya leaf curl Vikaspuri alphasatellite, Ageratum yellow vein India alphasatellite and Mesta yellow vein mosaic alphasatellite. Further, 33 elite lines of mungbean were screened against Legumoviruses-betasatellite complex. Three interspecific derivative lines of mungbean viz; SML2070, SML2071 and SML2063 were identified as highly resistant donors.ThesisItem Embargo Seed transmission of Pseudoperonospora cubensis and identification of host resistance against downy mildew of cucumber(Punjab Agricultural University, 2023) Kritika; Ritu RaniDowny mildew caused by Pseudoperonospora cubensis is a major disease of cucumber causing severe losses to farmers by affecting foliage. Surveys were conducted in different districts of Punjab for recording disease incidence and severity. It was deduced that the disease was most prominent in district Sangrur followed by Ludhiana, Hoshiarpur, Moga and Bathinda. During survey, the fruits collected from naturally infected vines revealed the presence of sporangia and oospores of P. cubensis in seeds when observed under microscope. To investigate seed transmission, seed grow out test was performed and P. cubensis was observed to be highest in the seedlings of Sangrur (33.33%) followed by Ludhiana (20.00%) Hoshiarpur (13.33%), Moga (6.67%) and no transmission was observed in fruits collected from Bathinda. Seed infectivity assays were conducted by artificial inoculation of healthy seeds and fruits using both sporangial and oospore inoculum. Microscopic studies revealed the presence of P. cubensis in seed coat as well as in embryo and seed to seedling transmission of P. cubensis was determined through seed grow out test. Transmission of P. cubensis from healthy seeds subjected to sporangial and oospore suspension was 40% and 26.66%, respectively. Transmission of P. cubensis from seeds of artificially inoculated fruits with sporangial suspension and oospores suspension was 46.66% and 20%, respectively. Molecular confirmation was done to detect the seed borne nature of the pathogen through DNA extraction from seed coat and embryo of naturally infected seeds and artificially inoculated seeds and fruits. PCR assays using ITS-4 and ITS-5 primers amplified 800bp band of P. cubensis. The pathogen has mainly reported to be soil borne but the present study showed that P. cubensis is also transmitted through seed. Forty cucumber genotypes were screened by artificial inoculation of plants in pots and under natural conditions in polyhouse as well as in laboratory conditions using detached leaf assay and leaf disc assay to identify sources against downy mildew. Cultivars PCG-10 and Punjab Kheera-1 were found to be moderately resistant.ThesisItem Restricted Characterization of Fusarium species associated with pokkah boeng disease of sugarcane(Punjab Agricultural University, 2023) Meena, Manisha; AnuradhaSugarcane (Saccharum spp. hybrid complex) is an important cash crop of India. Among the various fungal diseases, pokkah boeng caused by Fusarium spp. has emerged as an important disease in this crop. As the occurrence of this disease has been reported from Punjab till date the cultural, morphological and molecular aspects of this disease are not studied. Keeping in view, the present research was carried to characterize the Fusarium spp. associated with pokkah boeng disease of sugarcane. Survey was conducted in the sugarcane growing command area of sugar mills (nine co-operative and seven private) of Punjab during the year 2021-22. The maximum average incidence of pokkah boeng was reported on commercially grown variety Co 0238 (17.70 %) which depicted that the said variety is highly susceptible for pokkah boeng disease. Thirty isolates of Fusarium were obtained after isolation and purification from diseased samples collected during the survey. On the basis of pathogenicity tests, all the test isolates of Fusarium found to be virulent by producing necrotic lesion in detached leaf assay and typical symptoms of pokkah boeng in syringe method. Among all the isolates, Fs23 and Fs25 were highly pathogenic. The isolates showed significant variations on basis of their cultural and morphological characteristics and were categorized into various groups. Molecular study of isolates revealed that isolates Fs7, Fs20, Fs27, Fs29 showed 100 per cent similarity with the ITS, RPB2 and TEF-1α gene sequences of F. sacchari available in GenBank whereas isolates Fs13 and Fs17 showed 99 per cent similarity with F. proliferatum. Hence, the two species of Fusarium namely F. sacchari and F. proliferatum were identified as causal pathogens associated with pokkah boeng disease of sugarcane in Punjab. Genetic diversity estimate by seven ISSR primers showed high degree of polymorphism. Two isolates Fs16 (Jalandhar) and Fs18 (SBS Nagar) were found to be highly diverse among all test isolates. Sugarcane clones along with commercially released varieties were screened against pokkah boeng to identify the resistance sources in which 23, 18 and four clones/varieties showed resistant, moderately resistant and moderately susceptible disease reaction, respectively.ThesisItem Restricted Characterization of blast and bacterial blight resistance genes in basmati rice(Punjab Agricultural University, 2022) Vashisth, Tanvi; Jain, JyotiThe present study was conducted to evaluate MCF1 populations of basmati rice developed from complex crosses (designated as cross A and cross B). Phenotypic evaluation of cross A was done for resistance to neck blast (Pyricularia oryzae) using highly virulent isolate NB-7 under artificial inoculation conditions. Cross B was evaluated against neck blast (NB-7) as well as bacterial blight (Xanthomonas oryzae pv. oryzae) using two pathotypes PbXo-7 and PbXo-8 under artificial inoculation conditions. Among the MCF1 population comprising of 421 plants from cross A, 12 plants were immune, 6 were highly resistant, 30 were resistant and 59 were moderately resistant to neck blast isolate NB-7. A population of 103 plants from cross B showed immune response to neck blast in 9 plants, while 12 plants were resistant to pathotype PbXo-7 and 27 plants were resistant to PbXo-8. Both the crosses were also analyzed for known blast resistance genes (Pi54, Pi2, Pi9 and Pi68) and bacterial blight resistance genes (xa13 and Xa21). A total of 200 plants were tested in cross A, and 199 were found to have the Pi54 gene, while 155 had the Pi2 gene. Only 4 plants showed the presence of Pi9 gene in cross A. The combination of two blast resistance genes was found in 149 plants (Pi54 + Pi2) and in four plants there was a combination of three genes (Pi2 + Pi54 + Pi9). In the cross B, only two plants showed the presence of blast resistance gene (Pi9) and 40 plants showed the presence of Xa4 gene. Two plants were heterozygous for bacterial blight resistance gene (xa13) and four were heterozygous for Xa21. There were only two plants identified as having blast + BB resistance genes (Pi9+Xa4) and one plant showing two BB resistance genes (Xa21+Xa4). The assay of biochemical parameters indicated a significant increase in activity of peroxidase, PPO, PAL, catalase and hydrogen peroxide among resistant/moderately resistant genotypes as compared to the susceptible genotypes at 10 days after inoculation with P. oryzae. Out of 35 genotypes screened against leaf and neck blast phases under artificial inoculation conditions, none was found to be resistant to both the phases. Only two entries viz., Tetep and Pusa Basmati 1637 showed moderately resistant reaction to both neck and leaf blast with susceptibility index (Sx) value <3. Three genotype namely JJ92, UPR3519-18-1-1 and IET 15392 exhibited moderately resistant reaction to leaf blast but were moderately susceptible to neck blast under artificial inoculation conditions. Under natural epiphytotic conditions (hotspot location), five entries namely JJ92, UPR3519-18-1-1, IET 15392, Tetep and Pusa Basmati 1637 showed moderately resistant reaction to neck blast and resistant reaction to leaf blast. The current study has the potential to contribute towards strengthening ongoing blast and bacterial blight resistance breeding program by utilizing the identified donors harbouring single as well as multiple resistance genes to both the diseases.ThesisItem Restricted Characterization of Badnavirus (es) Species associated with Yellow Mosaic Disease of Citrus in Punjab(Punjab Agricultural University, 2023) Dhadly, Dalvir Kaur; Sharma, AbhishekCitrus is attacked by a large number of viral diseases worldwide, some being confined to a particular region. Among these Citrus yellow mosaic virus disease (CiYMVD) is restricted to India. Only one Badnavirus species i.e. Citrus yellow mosaic virus (CiYMV) has been reported to be associated with this disease. CiYMV is a double stranded DNA (dsDNA) plant pararetrovirus virus belonging to family Caulimoviridae. In the present study, Citrus growing districts of Punjab i.e. Fazilka, Hoshiarpur and Ludhiana were surveyed and a variety of symptoms were observed on different Citrus species like yellow specks, yellow spots, yellow patches, leaf puckering, leaf mottling, vein clearing and vein banding. Incidence of Citrus yellow mosaic virus disease ranged from 6.7-23.3 per cent in Punjab. For the detection of Badnaviruses, rolling circle amplification (RCA) followed by PCR approach was found reliable. Citrus yellow mosaic virus and Gulupa bacilliform virus A were characterized from Citrus samples L-11 and H-6 collected from Ludhiana and Hoshiarpur respectively. From mealybug samples M5 and M4, Banana streak virus and Sugarcane bacilliform virus were characterized. While Cacao red vein-banding virus was characterized from bael tree growing in the vicinity of Citrus orchard. Badnavirus positive Citrus species were T-budded (i.e. used as scions) onto Rough lemon and Carrizo rootstocks, the virus was successfully transmitted to scion leaves and confirm the occurrence of CiYMVD in Punjab.
