Shyam Sundar Lakshman et al. /Afr.J.Bio.Sc. 3(1) (2021) 129-145 Page 129 of 145 Volume 3, Issue 1, January 2021 Received : 28 July 2020 Accepted : 15 November 2020 Published : 01 January 2021 doi: 10.33472/AFJBS.3.1.2021.129-145 Article Info A bstract Present experiment was conducted on 32 sunflower genotypes (11 CMS lines and 21 Restorer lines) on the basis of their diverse origin, growth habit, phenology and adaptation with an object to assess variation in oil yield attributing traits. The total variability consisting heritable and non-heritable components of the characters were estimated by genotypic (GCV) and phenotypic (PCV) coefficient of variation, heritability and genetic advance (GA) and the best positive traits for sunflower improvement through selection and breeding were assessed. All the characters among the different genotypes exhibited significant variation. Oil yield was highly significant and positively correlated with seed yield (kg/ ha) (0.95), number of filled grain/ head (0.85), grain filling% (0.65), days to 50% flowering (0.417), plant height (0.33). Seed yield (kg/ ha) was highly significant and positively correlated with plant height (0.33), head diameter (0.30). Seed yield (kg/ ha) varied from 625 (CMS-16A) to 1120(CMS-302A) in lines and 576 (EC-601751) to 1221(R-630) in testers respectively. The highest 100 seed weight and hull content (%) was obtained from P-2-7-1A. Seed yield, oil yield (kg/ ha) and numbers of filled grains were obtained from EC 601978. Genotypes were classified into eight distinct clusters with a maximum inter distance observed between cluster VI and VII. The experiment assisted to identify the superior genotype among diverse genotypes of sunflower which can act as parents with desirable traits like number of filled grain/ head, volume weight/ 100 ml, 100- seed weight, oil content and seed yield/ plant for further breeding purposes. Keywords: Sunflower, Genetic variability, Character association, Genetic diversity, Yield attributing traits * Corresponding author: Nihar Ranjan Chakraborty, Assistant Professor, Dept. of Genetics and Plant Breeding, Institute of Agriculture, Palli Siksha Bhavana, Visva-Bharati, Sriniketan-731236, West Bengal, India. E-mail: nrchakraborty@gmail.com 2663-2187/ © 2021 African Journal of Biological Sciences. All rights reserved. African Journal of Biological Sciences ISSN: 2663-2187 Journal homepage: http:/ / www.afjbs.com Genetic variability, character association and divergence studies in sunflower (Helianthus annuus L. ) for improvement in oil yield Shyam Sundar Lakshman 1 , Nihar Ranjan Chakraborty 2 *, Sandip Debnath 3 and A chal Kant 4 1 Junior Breeder, AICRP Sunflower, Nimpith Centre-743338, West Bengal, India. E-mail: lakshmanshyam_ss@yahoo.co.in 2 Assistant Professor, Dept. of Genetics and Plant Breeding, Institute of Agriculture, Palli Siksha Bhavana, Visva-Bharati, Sriniketan-731236, West Bengal, India. E-mail: nrchakraborty@gmail.com 3 Assistant Professor, Dept. of Genetics and Plant Breeding, Institute of Agriculture, Palli Siksha Bhavana, Visva-Bharati, Sriniketan-731236, West Bengal, India. E-mail: sandip.debnath@visva-bharati.ac.in 4 Research Scholar, Dept. of Genetics and Plant Breeding, Institute of Agriculture, Palli Siksha Bhavana, Visva-Bharati, Sriniketan- 731236, West Bengal, India. E-mail: 786achalgupta90@gmail.com Research Paper Open Access Shyam Sundar Lakshman et al. /Afr.J.Bio.Sc. 3(1) (2021) 129-145 https://doi.org/10.33472/AFJBS.3.1.2021.129-145 © 2021 African Journal of Biological Sciences.This is an open access article under the CC BY license (https:/ / creativecommons.org/ licenses/ by/ 4.0/ ), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 1. Introduction Sunflower (Helianthus annuus L., 2n = 34)) is a very good source of vegetable oil due to high oil quality (linoleic acid-55-70%) and high concentration of poly unsaturated fatty acids with 35-42% oil content in seeds. Sunflower improvement progrm mainly depends on hybridization by using desirable parent with genetically diverse