Characterization of mycotoxic Fusarium species associated with ear rot of maize

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dc.contributor.advisorDr. Harleen Kaur
dc.contributor.authorHarinder Singh
dc.date.accessioned2024-05-31T13:55:41Z
dc.date.available2024-05-31T13:55:41Z
dc.date.issued2024
dc.description.abstractEar rot samples of maize (Zea mays L.) were collected during Kharif and spring seasons from different districts of Punjab. In all, 48 Fusarium isolates were obtained and purified for further studies. These isolates were grouped into six major groups based on morphological characteristics viz., colony color, pigmentation, type of mycelium, pattern of growth, growth rate and sporulation. Two species of Fusarium viz., F. verticillioides and F. proliferatum were identified using ITS, TEF-1α, RPB2, VERT- 1/VERT-2 gene specific primers. The sequences of four representative isolates-Fus 15, Fus 28, Fus 44 and Fus 45 when submitted to BLAST showed 99-100 per cent similarity with F. verticillioides and Fus 48 isolate had shown 97.91 per cent similarity with F. proliferatum. Further, out of 47 isolates of F. verticillioides VERTIF-1/VERTIF-2 primers 40 isolates with fumonisin producing ability. FUM13F /13R primers identified 36 isolates of F. verticillioides with fumonisin producing ability. FUM1 primers revealed that out of 48 Fusarium isolates, 41 isolates possessed FUM1 gene. Genetic diversity analysis of Fusarium isolates using 20 SSR primers revealed high degree of polymorphism and clustered 48 isolates into two major groups and seven subgroups. The primer 3H07 amplified maximum number of loci (6) ranging from 100-1400 bp in size and had highest PIC value of 0.76. On comparing the clusters of morphological, molecular and pathological characterization defined correlation could not be obtained among morphological characteristics, SSR pattern and pathological behavior of Fusarium isolates. For standardization of inoculation technique, we used four techniques viz., needle inoculation into the cob, toothpick inoculation in the ear, needle inoculation into the silk and spray silk inoculation, out of which needle inoculation into the cob technique gave highest mean disease index of 26.44 and 36.77 per cent during spring and Kharif seasons, respectively. Higher disease severity of FER was obtained when cobs were inoculated at 7 days after silking in both spring (19.34 %) and Kharif (32.16%) seasons. On comparing the seasons, Kharif season showed comparatively more disease severity (25.25 %) than spring season (17.1 %). Using this standardized technique, forty-five advanced maize germplasm lines were screened artificially against FER during Kharif 2021, disease severity varied from 27.77 to 96.29 per cent being lowest (27.77 %) in LM13×Teosinte-1-2-1-1-1 (BC1F1) and highest (96.29 %) in LM14×Teosinte-1-1-1-1 (BC1F1) line. Out of 45 lines, none of lines showed resistance reaction to FER, however 13 lines were found moderately resistant. Pathological behavior of all Fusarium isolates was studied on four hybrids (PMH 1, PMH 2, PMH 10 and PMH 13) and two inbreds (LM 13 and EML 173) of maize during spring 2022. Based upon their virulence, heatmap was generated and all isolates were clustered into seven groups. Group I isolates comprising Fus 15 (Ludhiana), Fus 23 (Jalandhar) and Fus 48 (Sirmour) were highly aggressive giving maximum disease severity of 68.74 per cent. Among the hybrids, PMH 1 showed minimum mean disease severity (34.16%) giving moderately resistant reaction to all Fusarium isolates. Among the inbreds, LM 13 showed minimum mean disease severity of 41.16 per cent giving moderately resistant reaction. The fumonisin production potential of F. verticillioides isolate- Fus 15 and F. proliferatum isolate-Fus 48 was observed on PMH 1 and PMH 2 hybrids under artificial inoculation conditions. Concentration of Fumonisin B1 (FB1) produced by Fus 15 and Fus 48 isolates was comparatively higher in PMH 2 than PMH 1 hybrid. Maximum fumonisin production of both FB1 and FB2 in maize grains was estimated at 21 days after incubation.
dc.identifier.citationHarinder Singh (2024). Characterization of mycotoxic Fusarium species associated with ear rot of maize (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810209543
dc.language.isoEnglish
dc.pages161
dc.publisherPunjab Agricultural University
dc.research.problemCharacterization of mycotoxic Fusarium species associated with ear rot of maize
dc.subPlant Pathology
dc.themeCharacterization of mycotoxic Fusarium species associated with ear rot of maize
dc.these.typePh.D
dc.titleCharacterization of mycotoxic Fusarium species associated with ear rot of maize
dc.typeThesis
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