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2020 - 20213
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Author: Gurwinder Kaur × Type: Thesis ×
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    Epidemiology and Management of Post harvest diseases of Kinnow mandarin
    (Punjab Agricultural University, Ludhiana, 2021) Gurwinder Kaur; Raheja, Sandeep
    Surveys 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.
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    ThesisItemOpen Access
    Epidemiology and Management of Post harvest diseases of Kinnow mandarin
    (Punjab Agricultural University, Ludhiana, 2021) Gurwinder Kaur; Raheja, Sandeep
    Surveys 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.
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    ThesisItemOpen Access
    Mapping and transfer of GENES/QTLs for nematode (Meloidogyne graminicola) resistance from Oryza glaberrima into Oryza sativa L.
    (Punjab Agricultural University, Ludhiana, 2020) Gurwinder Kaur; Vikal, Yogesh
    Rice root knot nematode (Meloidogyne graminicola) is one of the emerging constraints for rice production, causes about 50% yield losses in field conditions and 98% yield losses in pot experiments. The identification and exploitation of resistant rice genotypes is one of the economic and sustainable option to minimize the yield losses caused by M. graminicola infestations. The present investigation was undertaken to identify the QTLs associated with rice root knot nematode resistance as well as the transfer of resistance to elite rice cultivars. A total of 42 accessions of O. glaberrima along with O. sativa cultivar PR121 were screened in triplicates during kharif 2016 and kharif 2017 in nematode infested sick plot at initial nematode population density of one juvenile per gram of soil. Reproduction factor of rice root knot nematode among O. glaberrima accessions was found to be <1 while in O. sativa cultivar PR121, reproduction factor was >1. Out of 42 accessions, three accessions (IRGC102196, IRGC102538 and IRGC102557) were found to be highly resistant, thirty-three accessions were resistant, and six accessions were moderately resistant. Data on different morphological traits (plant height, root length, fresh shoot weight, fresh root weight, dry shoot weight and dry root weight) revealed that no statistically significant differences were found among O. glaberrima accessions whereas PR121 exhibited significant reduction in all growth parameters in nematode infested sick plot as compared to controlled conditions. The BC1F1 population derived from the cross of O. glaberrima acc. IRGC102206 × PR121 was used for mapping of rice root knot nematode resistance. The BC1F1 plants were screened against M. graminicola in triplicates and genotyped using 84 polymorphic SSR markers. Both phenotypic data and genotypic data was analyzed and a total of 13 QTLs associated with gall number, gall index and different morphological traits were mapped on chromosomes 1, 3, 4, 5, 6 and 8. Out of 13 QTLs, three QTLs associated with gall number were identified; two QTLs designated as qGN4.1and qGN4.2 were mapped on chromosome 4 and one QTL, qGN6.1, was mapped on chromosome 6. QTL associated with gall index (qGI6.1) was found to be co-localized with qGN6.1. Similarly, qGN6.1 QTL was co-localized with plant height and root length. Due to less coverage by SSR markers, we simultaneously performed BSA-QTLseq (Bulked segregant analysis coupled with QTL-seq approach) analysis and identified QTLs for nematode resistance on chromosomes 1, 2, 3, 4, 5, 6, 11 and 12. The genomic interval of all QTLs was narrowed down to 1–2 Mb using QTL-seq analysis. The development of SNP based molecular markers from identified QTL regions will further help to saturate the linkage map and to identify closely linked markers to rice root knot nematode resistance. The identified markers will further fasten the improvement of genotypes for rice root knot nematode resistance through marker assisted breeding approach. Based on introgressed genomic regions from O. glaberrima carrying QTLs for nematode resistance the BC1F1 resistant plants were selected and backcrossed to generate BC2F1 and subsequently BC3F1 progenies for transfer of nematode resistance in the background of PR121. The data generated from this study can serve as valuable genomic resources for rice breeding programmes.