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Tamil Nadu Agricultural University (2001)

Linkage Map Construction and Identification of QTLS for Downy mildew (Sclerospora gruminicula) resistance in Pearl Millet (Pennisetum glaucum (l.) R. Br.)

Azhaguvel, P

Titre : Linkage Map Construction and Identification of QTLS for Downy mildew (Sclerospora gruminicula) resistance in Pearl Millet (Pennisetum glaucum (l.) R. Br.)

Auteur : Azhaguvel, P

Etablissement de soutenance : Tamil Nadu Agricultural University.

Grade : PhD thesis 2001

Résumé
Pearl millet (Pennlsetu n glaucun ) is the slxth Important cereal crop It IS the staple food crop for poor farmers In the seml-arid troplcal reglons of lndla and West Africa The worst dlsease of pearl mlllet IS downy mlldew caused by a pseudo-fungal pathogen (Sclerospora grnr7i11i1soId) The genetlcs of th s host-pathogen system is poorly understood The study of reslstance has been hindered by both the host and the pathogen being outbreedlng and highly varlable and the segregatlon for host-plant resistance showing continuous variation Earller reports suggested that reslstance to downy mlldew IS a quantltatlve tralt controlled by polygenes In thls study a new pearl millet mapplng populat on waa developed from a res stant x susceptible cross A genetlc linkage map wlth a length of 561 8 cM wa constructed uslng RFLP markers along w th three morphological markers d, and d- dwarf plant height and P purple foltage colour The downy mlldew segregatlon pattern oC F-Fa progeriles from cross (IP 18293 x Tlfl 238D1) was studled agalnst six lndlan (Patancheru Jalna Jamnagar Jodhpur Durgapura and New Delhl) and two Afrlcan pathogen populat ons (Nlger and Mali) Pathogen population variab l ty w th reference to the reslstance behaviour among the segregating fam l es was studied and the best f t Mendellan segregation rat os were d scussed QTL mapplng was performed uslng Interval mapplng methods (MapmakeriQTL) and compos te interval mapping methods (QTL Cartographer) Seven different host-plant resistance QTLs are ident f ed against these eight pathogen populations There was a common reststance QTL for the Indian pathogen populat ons from Patancheru Jodhpur Jalna and Jamnagar on linkage group 2 Over-dominance of resistance was the inher tance pattern most commonly observed In the different screens All of the ident f ed resistance QTLs were from the res stant parental I ne IP 18293 Strategies for utilizing the dent f ed res stance QTLs for improving downy m ldew resistance of elite pearl millet hybr d parental lines were discussed

Présentation : ICRISAT

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Page publiée le 23 septembre 2012, mise à jour le 4 avril 2018