Mohanty, Iswar ChandraSaha, DebanjanaRout, G.R.Pradhan, S.K.Panda, S.Bastia, D.N.Garnayak, L.M2022-02-182022-02-182021https://krishikosh.egranth.ac.in/handle/1/5810182490TH - 6357Rice is one of the main staple food crops and a prominent source of calories for billions of people worldwide. Iron toxicity is a root related abiotic stress; affect the yield of rice in lowland production systems. High concentration of reduced iron (Fe2+) leads to iron toxicity and yield losses due to this varied from 15% to 100% depending on the genotype of rice, growth stage of plant, soil fertility and stress severity. The production of resistant rice genotypes through breeding programs is one of the most promising ways to increase yield under iron toxicity conditions. A powerful way to classify novel loci involved in complex phenotypic characteristics, is Genome-Wide Association Studies (GWASs).The most important aspect is morphological and genotyping characterization, according to this genome mapping method. In this present study, 150 germplasm lines of rice were screened in iron toxicity a hot spot and in control condition as well. Germplasm lines like Ganjamgedi, Kusuma, Pratikhsya, Ranidhan, Lalat etc are found iron toxicity tolerant by LBI scoring (IRRI 2013). Based on the morphological characterization, 120 panel populations have been created for the molecular characterization with 70 SSR markers. A total of 238 alleles were amplified with the 70 SSR markers and average alleles per locus were 4. The highest number of allele was 6 in the marker RM296. Minimum allele frequency was present in RM335 and lowest in RM174.The PIC value was maximum in RM335 and minimum value in RM339. Gene diversity (He) or expected heterozygosity was lowest in RM339 and highest observed in RM335. Estimation of K = 2 based on the ΔK determined by structure harvester, the entire population can be grouped into two sub groups (SP1 and SP2). While considering both the model GLM and MLM, RM346, RM492, RM293, RM201 and RM258 markers are strongly associated with leaf bronzing score. Significant association of RM293 present on chromosome 3 (193.4 cM) designated as qFeTox3.1and RM346 present on chromosome 7 (78.3 cM) designated as qFeTox7.1 was detected as novel QTL for Fe-toxicity tolerance.EnglishThesis