Sarvjeet SinghSethi, Sorabh2023-06-292023-06-292022Sethi, Sorabh (2022). Identification and characterization of QTLs governing key nitrogen fixation and nutrient traits in chickpea (C. arietinum L.) (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810197847The present study was conducted with an objective to identify and characterize the genetic factors underlying two broadly categorized traits viz., nutrient availability and nitrogen fixation related traits in chickpea and their relevance with economic yield in chickpea. The analysis of variance (ANOVA) revealed significant variation for all the traits under study among all genotypes across the years and environments (location) and also in pooled data. Measurement of skewness and kurtosis indicated presence of duplicate and complementary gene interaction for different traits. Correlation analysis indicated positive and significant correlation of seed yield with pods per plant. Similar association was observed between days to 50 % flowering and days to maturity. Apart from agronomic traits, no significant correlation was observed between nutrient and nitrogen fixation related traits. However, significant and positive correlation was observed among Fe and Zn content traits and also among different nitrogen fixation traits, but the pattern was not consistent for all the years and locations. For genotypic analysis, genotypic data was generated using genotyping by sequencing (GBS-ddRAD) approach. Total of 25,233 filtered SNPs were obtained based on 2X genomic coverage but post filtering, 520 SNPs were eventually used for generation of linkage mapping and bi-parental QTL mapping using QTL ICi mapping software. Total 14 QTLs have been identified, out of which four QTLs have been identified for nutrient traits i.e., three for grain Fe content while one QTL for Zn content. Six QTLs were identified for nodule number trait while for leghemoglobin content, total of four QTLs identified. In our study, no statistically significant QTL were identified for chlorophyll content and nodule dry weight. Promising lines for grain iron, zinc content and nitrogen fixation traits were identified which can be used as donor parents in chickpea breeding programme and developed markers can be used in marker assisted selection (MAS) for identifying desirable genotypes having allele of interest.EnglishThesis