The present investigation in sunflower (Helianthus annuus L.) was carried out to gather information on gene action and combining ability effects of parents, their hybrids, genotype x environment interaction and stability parameters for various phenological, agronomic/morphological traits and oil content. The experimental material comprised diverse CMS lines and testers crossed in Line x Tester design (4 x 10) to obtain 40 F1s. Hence parents, hybrids and 2 checks were grown during kharif, 2015 at two locations i.e. Udaipur (Rajasthan State) and Latur (Maharashtra State) while during rabi, 2015-16 at Latur only thereby evaluating in three environments following recommended package and practices. The heterosis for seed yield/ plant ranged between -30.41 to 36.63 %. The high specific combiner crosses recorded moderate level of heterosis, heterobeltiosis and economic heterosis. CMS 234A X RHA 138-2, CMS 234A x EC 601957, ARM 249A x EC 623023, CMS 234A x R 16 and ARM 249 x RHA 138-2 could be adjudged as the best heterotic crosses for yield and its component traits viz. head diameter, Seed filling percentage, volume weight and 100-seed weight where as CMS 234A X RHA 138-2, ARM 249A x EC 623023, CMS 234A x R 16 for yield, oil content and hull content. These crosses also manifested high per se performance, good GCA effects of at least one parent and significant SCA effects.