Person: Singh, P.K.
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Singh
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P.K.
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Singh, P.K.
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0000-0003-4610-3120 4 results
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- Evaluation of CIMMYT germplasm for resistance to leaf spotting diseases of wheat(Czech Academy of Agricultural Sciences, 2011) Singh, P.K.; Duveiller, E.; Singh, R.P.The leaf spotting disease complex is a major biotic constrain in enhancing grain production in the major wheat growing regions. Two leaf spotting diseases, tan spot, caused by an ascomycete fungus Pyrenophora tritici-repentis, and Stagonospora nodorum blotch besides causing average yield losses of 5?10%, cause significant losses in grain quality by red smudge, black point and grain shriveling. Conservation agriculture in combination with wheat monoculture involving cultivation of susceptible cultivars has resulted in frequent onset of leaf spots epidemics worldwide. Development of resistant wheat cultivars, in conjunction with crop rotation, will provide an effective, economical, and environmentally safe means of controlling leaf spot. International Maize and Wheat Improvement Center (CIMMYT), Mexico has initiated major efforts to mitigate the threat of tan spot. Efforts include screening of wheat germplasm, identification of new sources of resistance, characterization of new tan spot resistance genes through classical and molecular genetic analysis, incorporation of resistance into adapted cultivars, and assessing the variability in the tan spot fungus. Screening studies reveal that elite CIMMYT germplasm has high level of resistance to tan spot caused by P. tritici-repentis race 1. These germplasm have diverse genetic make-up and the resistance is likely broad based. Association mapping studies done with CIMMYT germplasm reconfirmed the presence of previously identified genomic regions for tan spot resistance; however, novel genomic regions on long arm of chromosomes 6A and 7B have also been identified. Studies done to date indicate that CIMMYT germplasm possess high level diverse genetic based resistance to tan spot of wheat. Efforts are in place to develop desired wheat cultivars with tan spot resistance. Virulence studies indicate presence of P. tritici-repentis race 1 only with some variability in level of toxin Ptr ToxA produced in each of the 76 isolates studied.
Publication - Multi-trait and multi-environment QTL analyses for resistance to wheat diseases(Public Library of Science, 2012) Singh, S.; Hernandez, M.V.; Crossa, J.; Singh, P.K.; Bains, N.; Singh, K.; Sharma, I.Background: Stripe rust, leaf rust, tan spot, and Karnal bunt are economically significant diseases impacting wheat production. The objectives of this study were to identify quantitative trait loci for resistance to these diseases in a recombinant inbred line (RIL) from a cross HD29/WH542, and to evaluate the evidence for the presence loci on chromosome region conferring multiple disease resistance. Methodology/Principal Findings: The RIL population was evaluated for four diseases and genotyped with DNA markers. Multi-trait (MT) analysis revealed thirteen QTLs on nine chromosomes, significantly associateed with resistance. Phenotypic variation explained by all significant QTLs for KB, TS, Yr, Lr diseases were 57%, 55%, 38% and 22%, respectively. Marginal trait analysis identified the most significant QTLs for resistance to KB on chromosomes 1BS, 2DS, 3BS, 4BL, 5BL, and 5DL. Chromosomes 3AS and 4BL showed significant association with TS resistance. Significant QTLs for Yr resistance were identified on chromosomes 2AS, 4BL and 5BL, while Lr was significant on 6DS. MT analysis revealed that all the QTLs except 3BL significantly reduce KB and was contributed from parent HD29 while all resistant QTLs for TS except on chromosomes 2DS.1, 2DS.2 and 3BL came from WH542. Five resistant QTLs for Yr and six for Lr were contributed from parents WH542 and HD29 respectively. Chromosome region on 4BL showed significant association to KB, TS, and Yr in the population. The multi environment analysis for KB identified three putative QTLs of which two new QTLs, mapped on chromosomes 3BS and 5DL explained 10 and 20% of the phenotypic variation, respectively. Conclusions/Significance: This study revealed that MT analysis is an effective tool for detection of multi-trait QTLs for disease resistance. This approach is a more effective and practical than individual QTL mapping analyses. MT analysis identified RILs that combine resistance to multiple diseases from parents WH542 and/or HD29.
Publication - 8th International symposium on mycosphaerella and stagonospora diseases of cereals: book of abstracts(CIMMYT, 2011) Duveiller, E.; Singh, P.K.Abstract Book of the VIII International Symposium on Cereal Diseases by Mycosphaerella and Stagonospora held in Mexico City, Mexico, from September 10 to 14, 2011.
Publication - Wheat diseases and pests: a guide for field identification(CIMMYT, 2012) Mezzalama, M.; Duveiller, E.; Singh, R.P.; Singh, P.K.; Dababat, A.A.This booklet is designed as a quick guide for identifying wheat and triticale diseases in the field. It is intended primarily for agricultural researchers, technicians, and farmers in developing nations, but will also be of value to others. The text comprises a brief description of the major wheat and triticale diseases, insect pests, nematodes, physiologic and genetic disorders, and mineral and environmental stresses. Complementing this text and as an aid to identification are numerous color photographs1, drawings2 and, in the center of the booklet, a brief diagnostic key. In the case of specific causal organisms, the perfect stage name or telemorph (when known) is followed by the imperfect stage name or anamorph in parentheses. While most of the diseases, pests, disorders, or stresses included can be economically significant, some are not and are presented only because they are unique or might be confused with more economically significant problems.
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