Assessment of stableness for male sterility in newly developed CMS lines in sunflower (Helianthus annuus L.)

Diversification of parental lines both CMS and restorer inbreds are the absolute necessities in sunflower heterosis breeding programme for developing hybrids with high yield, high oil content as well as biotic and abiotic stress resistance. A total of 11 inbred lines with high oil content and high yield from TNHSF 239 population and also promising inbreds from a three way cross (TNHSF 239 x Wild 1-3-2) x Morden derivatives were utilized in conversion programme for developing new CMS lines in sunflower. Eleven newly developed CMS lines from BC₆ back cross population were evaluated for their stability across three locations namely Coimbatore, Vamban and Chettinad. All the CMS lines except COSF8A and COSF 9A exhibited stable sterility across the locations and all the maintainers showed 100% fertility at all the three locations. Three CMS lines namely COSF 6A, COSF 7A and COSF 12A were identified for their high oil content (40-43%). Hybrids of these CMS lines showed positive heterosis for yield and yield attributing traits. Therefore, newly developed promising CMS lines can be effectively utilized in hybrid breeding programme for developing high yielding and high oil hybrids in sunflower.