Golakiya B. A.SANGHANI ATUL ODHAVJIBHAI2016-09-212016-09-212014-10http://krishikosh.egranth.ac.in/handle/1/78103Key words: Linkage, QTL, DMR, Linkage group, SSR, LOD. Present experiment on “LINKAGE AND QTL MAPPING FOR DOWNY MILDEW RESISTANCE IN PEARL MILLET (Pennisetum glaucum (L.) R. Br.)” was conducted at Department of Biotechnology, Junagadh Agricultural University, Junagadh, The study was formulated to improve the yield potential of hybrids of J-2372, which is one of the elite and important restorer lines used in hybrid breeding programs in Gujarat. Identification of downy mildew resistance genomic regions was set as an objective. Downy mildew of pearl millet is one of the most important devastating diseases limiting pearl millet productivity. DNA-based marker tools facilitated better understanding of the inheritance and expression of downy mildew. To fulfill the objectives, the two pearl millet inbred parental lines were crossed to F1, and the F1 progenies were selfed to produced 125 segregating F2 mapping population progenies for generating marker data using 24 SSR out of 80 markers exhibiting clear polymorphism between parental lines. The downy mildew screening of segregating F2 population progenies based on J-2480 x J-2372 against downy mildew was done at JAU., Jamnagar. R QTL interval mapping method identified two downy mildew QTLs on Linkage Group 1 and Linkage Group 6. This best single-QTL model detected by interval mapping on Linkage Group 1 (M1 marker) recorded a high LOD score of 6.3 with map position 14.8 and explained 46.4 % of recorded phenotypic variation in downy mildew incidence among 125 F2 progenies and Linkage Group 6 (M44 marker) recorded a LOD score of 1.6 with map position 56.07 and explained 36 % of recorded phenotypic variation in downy mildew incidence among 125 F2 progenies against Sclerospora graminicola pathogen The confidence interval detected that the position between 10-15 cM on linkage group 1 was responsible for the resistance against downy mildew in pearl millet. The effect plot for marker M1 indicated that the resistance against the downy mildew was governed by dominant inheritance and can be easily used for the transfer of trait though marker assisted selected using marker M1. In present study, downy mildew resistance QTLs detected exhibited over-dominant modes of inheritance, and DMR resistant QTLs come from resistant male parent J-2480. These identified DMR QTLs from J-2480 can now be transferred to genetic backgrounds of elite pearl millet hybrid parental lines (J-2372) through marker-assisted backcrossing programs. Flanking markers of the identified QTLs can facilitate selection of resistant progenies during the backcrossing process, where as other marker loci can be used in reducing the length of the donor segments carried along with the introgressed DM resistance genes and/or selecting for recovery of recurrent parent alleles on non-carrier chromosomes.enMILLETThesis