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ThesisItem Open Access Biocontrol of fusarial wilt of bottle gourd(Punjab Agricultural University, Ludhiana, 2019) Ruchika, Ruchika; Narinder SinghThe wilt of bottle gourd caused by Fusarium oxysporum is a serious disease in bottle gourd growing areas of Punjab. Rhizosphere soil samples were collected from bottle gourd fields of Ludhiana, Kapurthala and Bathinda districts of Punjab in order to analyze the antagonistic microflora. Five isolates of Trichoderma and three isolates of Pseudomonas were isolated and screened in vitro for their antagonistic activity against Fusarium oxysporum. Among the various isolates, two isolates of Trichoderma (T1 and T2) and one isolate of Pseudomonas (P1) showed good inhibition against Fusarium oxysporum under lab conditions. Trichoderma isolate T2 showed maximum inhibition of Fusarium oxysporum (76.33 % and 65.83%) in dual culture and volatile assay, respectively. On Molecular characterization the selected isolates T1 and T2 were identified as Trichoderma asperellum and isolate P1 was identified as Pseudomonas aeruginosa. The selected isolates were then applied as seed, soil and seed + soil treatments using 10g and 15g formulation of each antagonist to check their efficacy against Fusarium oxysporum in two different seasons (March and June) under field conditions. Maximum germination (91.67% and 87.50%) and maximum disease inhibition (92.31% and 86.67%) was found in case of chemical treatment followed by Trichoderma asperellum isolate T2 with a germination of 87.50 per cent and a disease reduction of 84.62 and 80.00 per cent in March and June, respectively. Maximum yield (235.99q/acre and 229.00q/acre) along with maximum total length (5.43 m and 4.83 m) was obtained in case of Trichoderma asperellum isolate T2 in March and June, respectively due to disease control and the plant growth promoting behaviour of the antagonist. The results of rhizospheric competence showed that enough propagules of the antagonists were present throughout the growing season to effectively manage the wilt pathogen. Talc based bioformulation of the selected antagonists showed maximum shelf life on storing at 0°C and packing in polythene bags.ThesisItem Restricted BIOCHEMICAL AND HISTOPATHOLOGICAL STUDIES IN BARLEY FOR COVERED SMUT (Ustilago hordei) RESISTANCE(Punjab Agricultural University, Ludhiana, 2019) Jashandeep Singh; Vineet KumarCovered smut caused by Ustilago hordei is an important disease of barley in India. In present study, biochemical basis of resistance, histopathological & ultrastructural changes and identification of sources of resistance to U. hordei were undertaken. The biochemical basis of resistance was studied on a set of three barley cultivars viz. PL 426 (resistant), PL 891 (moderately susceptible) and VJM 201 (susceptible). Maximum level of total phenols (0.64 units min-1 g-1 fresh weight) and activity of peroxidase (POD) (86.70 units min-1 g-1 fresh weight) was recorded in PL 426 whereas maximum activity of polyphenoloxidase (PPO) (89.30 units min-1 g-1 fresh weight) and phenylalanine ammonia lyase (PAL) (1.39 units min-1 g-1 fresh weight) was recorded in PL 426 and PL 891, respectively. The aqueous extract of seedlings of PL 426 (resistant variety) inhibited 98% of teliospores at 100% concentration. Ultrastructural comparison of compatible and incompatible Hordeum vulgare-Ustilago hordei, host-pathogen interaction done with scanning electron microscope showed germinated teliospores and trailing hyphae all over the host surface in the compatible interaction. Whereas, in incompatible interaction the teliospores were intact and extracellular polysaccharides were present completely adjacent to teliospores which might be involved in hindering the germination of teliospores. Eighty three germplasm accessions comprising of 74 germplasm lines and 9 varieties were evaluated against covered smut disease. Among the 9 varieties, 5 varieties namely HBL 113, HBL 391, HBL 316, DWRUB 92 and DWRUB 123 were found to be completely free from covered smut disease under field conditions at two locations viz. Ludhiana and Faridkot. PL 172 and PL 891 were categorized as moderately resistant and moderately susceptible, respectively. Among 74 germplasm lines tested at both locations, 41 showed high level of resistance and were found free from disease. BL 1562, BL 1656, BL 1627 and BL 1562, BL 1652 lines were found to be resistant at PAU, Ludhiana and RRS, Faridkot, respectively. 17 germplasm lines showed moderate resistance against covered smut.ThesisItem Open Access Etiology of charcoal rot of maize caused by Macrophomina phaseolina (Tassi.) Goid. in Punjab(Punjab Agricultural University, Ludhiana, 2019) Ahmadi, Khalilullah; Harleen KaurFive different stages (55, 65, 75, 85 and 95 days old plants) of three maize hybrids viz. PMH 10, DKC 9108 and PMH 2 were evaluated for determination of most susceptible growth stage against charcoal rot during spring season. The data revealed that 75 days old plant was the most susceptible growth stage for charcoal rot. At this particular stage, mean disease severity (60.83 %) was maximum, resulting in minimum mean grain yield (55.27 q/ha).This stage also coincides with tasseling and silking stage of the plant. The effect of five different sowing dates on disease severity of charcoal rot of five maize hybrids during spring 2018 and 2019 revealed that crop sown on 20th January suffered minimum disease severity (40.91 and 36.3 %) resulting in maximum grain yield (74.27 and 77.89 q/ha) during spring 2018 and 2019 respectively. The plant height and cob height was found maximum on this date. As sowing date was delayed, severity of charcoal rot increased, thus decreasing grain yield, plant height and cob height. Among meteorological factors, disease severity was found positively correlated with mean temperature (+0.98) and negatively correlated with mean relative humidity (-0.92) and total rainfall (-0.90). The effect of three irrigation schedules (additional irrigation at tasseling and silking stage, local practice and stress at tasseling and silking stage) on the development of charcoal rot showed that application of an additional irrigation at tasseling and silking stage had least mean disease severity (36.28%) compared to other irrigation schedules and resulted in highest mean grain yield (72.61 q/ha). Water stress at tasseling and silking stage of the crop aggravated the disease development. Fifty four maize germplasm lines were evaluated artificially against charcoal rot, out of which five germplasm lines (PML-81, LTY 9808, JCY 13-1-1, SNL 172470 and SNL 172475) were found resistant, thirty moderately resistant, seventeen moderately susceptible and two of them were found highly susceptible. The maize hybrids sown in month of January and February coupled with additional irrigation at tasseling and silking stage resulted in low disease severity of charcoal rot, thus maximizing the grain yield. The germplasm lines found resistant after artificial screening of charcoal rot at the most susceptible growth stage (75 - 85 days old plants) during spring season could be successfully utilized in future breeding programme for maize improvement.ThesisItem Restricted Integrated management of Meloidogyne incognita and Rhizoctonia bataticola in root rot disease complex in mungbean(Punjab Agricultural University, Ludhiana, 2019) Rohit Kumar; Dhillon, Narpinderjit KaurMungbean crop is attacked by number of soil and air borne pathogens. Of the different soil borne pathogens; root-knot nematode (Meloidogyne spp.) is an important pathogen affecting growth and production of mungbean. Another soil and seed borne pathogen, Rhizoctonia bataticola causes root rot disease of mungbean. Meloidogyne incognita and R. batalicola being soil borne organisms may affect each other activity besides influencing the responses in their common host mungbean. Studies were conducted on the build-up of root knot nematode in nine different genotypes in summer and kharif season. The reaction of different genotypes was varied in two seasons. Eight of the nine genotypes were found to support multiplication of root knot nematode while decrease in nematode population was observed in only one genotype ML 2056. M. incognita populations in soil were observed to be significantly higher in kharif season in four genotypes viz., SML 1906, TMB 37, SML 1827, SML 1900 in comparison to summer season while in the other five genotypes there was no significant difference in the nematode population in two seasons. The interaction of M. incognita and R. bataticola revealed that higher incidence of root rot disease and maximum decrease in plant growth parameters was recorded in simultaneous inoculation of Meloidogyne incognita and R. bataticola. Of the one hundred two genotypes screened against M. incognita in summer and kharif mungbean; only ten genotypes were found to be moderately resistant. Of the eighty eight mungbean genotypes screened against Rhizoctonia bataticola only ten were moderately resistant. In multiple disease resistance studies, four genotypes which were moderately resistant against both pathogens were evaluated. Breakdown of resistance was observed in ML2581 and ML2560, while ML 2056 showed moderately susceptible reaction and ML2607 was observed to be moderately resistant against both pathogens. Integrated management of root knot nematode and R. bataticola in mungbean revealed that combined application of Bionematon@4l/ha + neem cake@1 t/ha + Captan (seed Treatment) was more effective than the individual application of chemical, bioformulation or cakes.ThesisItem Restricted Integrated management of Meloidogyne incognita and Rhizoctonia bataticola in root rot disease complex in mungbean(Punjab Agricultural University, Ludhiana, 2019) Rohit Kumar; Dhillon, Narpinderjit KaurMungbean crop is attacked by number of soil and air borne pathogens. Of the different soil borne pathogens; root-knot nematode (Meloidogyne spp.) is an important pathogen affecting growth and production of mungbean. Another soil and seed borne pathogen, Rhizoctonia bataticola causes root rot disease of mungbean. Meloidogyne incognita and R. batalicola being soil borne organisms may affect each other activity besides influencing the responses in their common host mungbean. Studies were conducted on the build-up of root knot nematode in nine different genotypes in summer and kharif season. The reaction of different genotypes was varied in two seasons. Eight of the nine genotypes were found to support multiplication of root knot nematode while decrease in nematode population was observed in only one genotype ML 2056. M. incognita populations in soil were observed to be significantly higher in kharif season in four genotypes viz., SML 1906, TMB 37, SML 1827, SML 1900 in comparison to summer season while in the other five genotypes there was no significant difference in the nematode population in two seasons. The interaction of M. incognita and R. bataticola revealed that higher incidence of root rot disease and maximum decrease in plant growth parameters was recorded in simultaneous inoculation of Meloidogyne incognita and R. bataticola. Of the one hundred two genotypes screened against M. incognita in summer and kharif mungbean; only ten genotypes were found to be moderately resistant. Of the eighty eight mungbean genotypes screened against Rhizoctonia bataticola only ten were moderately resistant. In multiple disease resistance studies, four genotypes which were moderately resistant against both pathogens were evaluated. Breakdown of resistance was observed in ML2581 and ML2560, while ML 2056 showed moderately susceptible reaction and ML2607 was observed to be moderately resistant against both pathogens. Integrated management of root knot nematode and R. bataticola in mungbean revealed that combined application of Bionematon@4l/ha + neem cake@1 t/ha + Captan (seed Treatment) was more effective than the individual application of chemical, bioformulation or cakes.ThesisItem Restricted Management of botrytis gray mold (Botrytis cinerea Pers. ex. Fr.) of chickpea through host resistance and fungitoxicants(Punjab Agricultural University, Ludhiana, 2019) Jagmeet Singh; Upasana RaniBotrytis gray mold caused by Botrytis cinerea is one of the most destructive diseases of chickpea. Maximum disease was observed in seedling inoculated from 5th to 25th February under 100 percent shade condition and disease development was more on PBG 5. Evaluation of chickpea inter-specific derivative lines (115) and germplasm (68) revealed that none of the line possessed high degree of resistance. Six inter-specific derivative lines (9054, 9056, 8007, 8018, 8022 and 8026) and two germplasm lines (GL-93011and GL-98010) showed moderately resistant reaction. Out of forty seven accessions of wild Cicer species, sixteen accessions (C. judaicum ILWC-95, C. judaicum ILWC-182, C. judaicum ILWC-185, C. judaicum ILWC-17148, C. reticulatum ILWC-237, C. reticulatum ILWC-141E, IC-525691, IC-525197, EC-366339, EC-366342, C. pinnatifidum ILWC-225, C. judaicum ILWC-223, C. pinnatifidum ILWC-261, C. pinnatifidum ILWC-0, C. pinnatifidum ILWC-263 and C. pinnatifidum ILWC-212) gave resistant reaction. Out of twenty seven lines derived from the cross of three parents (C. pinnatifidum 188, ICCV 96030 and PBG 1), only three lines (10008, 10009 and 10011) showed C. pinnatifidum 188 specific segment and moderately resistant reaction. These three lines were flanked by primers GA-22, GA-24, GA-105, NCPGR-127 and NCPGR-141. Testing of fungitoxicants by poison food technique (in vitro) showed that maximum per cent growth inhibition of 78.66 and 84.54 respectively was found in azoxystrobin + difenconazole 325 SC even at low concentration of 1 and 5 ppm respectively. Next best fungitoxicant propiconazole 25 EC gave more than 90 percent inhibition at 50 ppm. Similar results were achieved when these fungitoxicants were evaluated for sporulation at their respective concentrations. ED50 value of 1 μl ml-1 was achieved in azoxystrobin + difenoconazole, propiconazole and carbendazim. Non-systemic fungitoxicants were found to be non-effective against the pathogen. Azoxystrobin + difenoconazole 325 SC @0.1 percent with disease reduction of 88.68 per cent over control with per cent disease index of 7.72 as compared to check (68.24%) was followed by propiconazole 25 EC @ 0.1 percent disease reduction of 85.85 per cent over control with per cent disease index of 9.65 per cent.ThesisItem Open Access Biocontrol of fusarial wilt of bottle gourd(Punjab Agricultural University, Ludhiana, 2019) Ruchika; Narinder SinghThe wilt of bottle gourd caused by Fusarium oxysporum is a serious disease in bottle gourd growing areas of Punjab. Rhizosphere soil samples were collected from bottle gourd fields of Ludhiana, Kapurthala and Bathinda districts of Punjab in order to analyze the antagonistic microflora. Five isolates of Trichoderma and three isolates of Pseudomonas were isolated and screened in vitro for their antagonistic activity against Fusarium oxysporum. Among the various isolates, two isolates of Trichoderma (T1 and T2) and one isolate of Pseudomonas (P1) showed good inhibition against Fusarium oxysporum under lab conditions. Trichoderma isolate T2 showed maximum inhibition of Fusarium oxysporum (76.33 % and 65.83%) in dual culture and volatile assay, respectively. On Molecular characterization the selected isolates T1 and T2 were identified as Trichoderma asperellum and isolate P1 was identified as Pseudomonas aeruginosa. The selected isolates were then applied as seed, soil and seed + soil treatments using 10g and 15g formulation of each antagonist to check their efficacy against Fusarium oxysporum in two different seasons (March and June) under field conditions. Maximum germination (91.67% and 87.50%) and maximum disease inhibition (92.31% and 86.67%) was found in case of chemical treatment followed by Trichoderma asperellum isolate T2 with a germination of 87.50 per cent and a disease reduction of 84.62 and 80.00 per cent in March and June, respectively. Maximum yield (235.99q/acre and 229.00q/acre) along with maximum total length (5.43 m and 4.83 m) was obtained in case of Trichoderma asperellum isolate T2 in March and June, respectively due to disease control and the plant growth promoting behaviour of the antagonist. The results of rhizospheric competence showed that enough propagules of the antagonists were present throughout the growing season to effectively manage the wilt pathogen. Talc based bioformulation of the selected antagonists showed maximum shelf life on storing at 0°C and packing in polythene bags.ThesisItem Open Access Diversity and management of aflatoxin producing Aspergillus spp. in groundnut(Punjab Agricultural University, Ludhiana, 2019) Belludi, Rakesh; Sandhu, P.S.Survey was conducted in the major groundnut growing states of India to collect the groundnut samples to detect the aflatoxin contamination. Out of 53 samples collected, 32 isolates were isolated, among them six were of Aspergillus niger, which were proved to be nontoxic by ammonia vapour test. Other 26 isolates were carried for further identifications. Through this study, all 26 isolates were proved to be of A. flavus. Based on the morphological quantitative characters like growth rate, size of the conidia and conidiophores, all the isolates were classified into five clusters by multivariate cluster analysis at 93.13 per cent similarity level. Further, all the isolates were assessed with the qualitative tests to detect the toxigenic strains. In bioassay eight isolates were proved toxigenic and isolate afl 26 from Telangana was the most toxigenic. From ammonia vapour test, it was proved that 14 isolates were toxigenic, among these afl 26 isolate from Telangana was again proved highly toxic. All the isolates which proved toxic were further carried to quantify the aflatoxin production through HPLC. According to this, nine out of 17 isolates were proved to produce aflatoxin B2 above detectable levels, which were above the safe limits of Indian and USFDA standards. The field experiments were conducted to evaluate the effects of cultural practices viz., date of sowing, soil amendments like FYM & lime and bioagents like Trichoderma harzianum & Pseudomonas fluorescens on aflatoxin production. It showed that early sowing of crop in April month reduces the collar rot infection, but it aggravates the aflatoxin producing fungi. Application of FYM and lime reduces the aflatoxin contamination and meanwhile increased the pod yield of the groundnut. Whereas bioagents also reduced the aflatoxin contamination. In another experiment to evaluate the effect of storage conditions on aflatoxin production, higher aflatoxin contamination was found in the pods (inoculated with toxigenic strain afl 26) stored at 35°C with >20 per cent moisture content, hence it is recommended to store the pods at 15°C with 12-15 per cent moisture content.ThesisItem Open Access Integrated management of mango anthracnose(Punjab Agricultural University, Ludhiana, 2019) Harinder Singh; Arora, AnitaAnthracnose caused by Colletotrichum gloeosporioides is one of the most destructive diseases of mango. During survey it was observed that the disease was prevalent in Gurdaspur, Hoshiarpur and Pathankot districts with highest disease incidence in Pathankot (43.36 %) and lowest in Hoshiarpur (39.22 %). The disease appeared as irregular, dark brown to black necrotic lesions with light centres on mango leaves. The fungus produced septate and hyaline hyphae, which were initially cottony white and become gray in later stages. The conidia were cylindrical or oblong, straight with rounded ends, non-septate with oil droplets having 13.10-16.50 μm length and 3.90-4.30 μm breadth. The acervuli produced in the culture were round to irregular in shape, dark brown to black coloured with dark brown to black, erect setae measuring 60.90-64.30 × 2.50-3.60 μm. All the cultivars had shown susceptible reaction under laboratory and field conditions except the cultivar Malika which was highly susceptible under laboratory conditions. The systemic fungicides azoxystrobin and propiconazole were highly effective in inhibiting the mycelial growth (100%) of pathogen at 100 μl/ml. The ED50 value of azoxystrobin was ˂5 μl/ml and ED90 value ˂25 μl/ml. Mancozeb was the least effective fungicide in inhibiting the mycelial growth (32.89%) of the fungus. The fungicides azoxystrobin and propiconazole were significantly effective in reducing percent disease index and providing disease control at both the locations Ladhowal (Ludhiana) and Gangian (Hoshiarpur). Thiophanate methyl was the next best treatment in reducing percent disease index.
