Patil, B.R.Kazi, Mohammed Asim M.2021-07-152021-07-152016-07https://krishikosh.egranth.ac.in/handle/1/5810170537Cotton fibers are single-celled seed trichomes of major economic importance in textile industry. Considering the importance of fiber quality, 225 genotypes of Gossypium anomalum L. introgressed G. arboreum L. lines were evaluated for their performance, assessment of variability, association and path co-efficient analysis. The study also focused on dissecting the molecular and biochemical basis of fiber strength through real-time PCR analysis and histological study using contrasting genotypes Arb-1 (22.9 g/tex) and Arb-2 (19.7 g/tex) for fibre strength. The research was conducted under rainfed condition at botanical garden, MARS, University of Agricultural Sciences, Dharwad during kharif 2013. The genotypes registered significant variability for all the characters studied and association analysis revealed that seed cotton yield was positively associated with number of sympodia, boll number, plant height, boll weight, seed index and number of locules. Plant height, number of sympodials, number of bolls, boll weight, lint index, seed index and number of locules contributed to increased seed cotton yield per plant. Also, since these traits had direct significant effect on seed cotton yield, emphasis can be laid on these attributes. The real-time PCR analysis revealed that the CesA4, CesA7, CesA8 and GhMT1 genes were upregulated during 24 DPA (initiation of secondary cell wall synthesis) and 30 DPA (secondary cell wall synthesis) which are the important stages in synthesizing maximum cellulose contributing towards the higher fiber strength. The expression studies revealed upregulation of these genes in the genotype possessing high fibre strength. Histological and biochemical results on seed cotton fiber growth stages revealed deposition of cellulose at 24 and 34 DPA, which conferred high fiber strength.EnglishThesis