Sheoran, R.K.Sachin Kumari2018-10-292018-10-292018http://krishikosh.egranth.ac.in/handle/1/5810082437The present study entitled “Studies on genetic divergence, stability, heterosis and combining ability in sunflower (Helianthus annuus L.)” was undertaken to estimate genetic divergence, economic heterosis, combining ability with the objective of exploring possibilities of their commercial utilization and stability analysis in four different environments. The material for the present investigation comprised of seventy five hybrids developed by making crosses between fifteen female parents (lines) and five male parents (testers) in line x testers mating design along with one standard checks (HSFH 848). The crosses were made at research area of Oilseed Section, Department of Genetics and Plant Breeding, CCS HAU, Hisar during the spring season of 2014. Hybrids and parents were evaluated under four different environments i.e. Summer 2014, last week of August (E1) and First week of Sept. (E2) and during spring 2015, i.e. first week of February (E3) and last week of February (E4). Data on five randomly selected plants from each genotype in each replication were recorded on different quantitative characters viz. plant height (cm), head diameter (cm), stem diameter (cm) days to 50% flowering, days to maturity, hundred seed weight (g), seed yield per plant (g), oil content (%), hull content (%), percent seed filling, germination (%), electrical conductivity (μScm-1g-1), viability (%), vigour index I, vigour index II, palmitic acid (%), stearic acid (%), oleic acid (%) and linoleic acid (%) in all the test environments. Based on Euclidean minimum distance, all the genotypes were grouped into six clusters which showed the presence of enough amount of genetic diversity in the present material. The cluster IV was having highest numbers of genotypes followed by clusters V,I,VI, II, III .The intra-cluster distances were less than that of inter cluster distances which showed that there was narrow genetic variation within the clusters while there was maximum genetic variation in between the clusters. Hybrids CMS 207 A x HRHA 5-3, CMS 852 A x RHA 271, CMS 207 A x RHA 297, CMS 234 A x 6D-1 and CMS 207 A x 6D-1 were found better and superior for stability, combining ability and heterosis studies for seed yield and its contributing trait and also for oil content. The combining ability analysis revealed that non- additive variance in the expression of all the traits. Among lines CMS 207 A, CMS 148 A, CMSH 91 A, CMS 17A and testers RHA 271 and HRHA 5-3 were the good general combiners. The hybrids with good heterotic value, good GCA, SCA and better value of stability could be directly used for heterosis breeding because of their dominant nature. The use of genotypes in hybridization from these results is likely to produce more heterotic combination in future.ennullThesis