Mutagenic Effects of Gamma Rays and Ems on Germination, Plant Survival, Lethality, and Pollen Sterility in M₁ and M₂ Generations of Sunflower (Helianthus Annuus L.)

Abstract

Induced mutagenesis can generate useful variability in sunflower while also causing biological injury that depends on mutagen type and treatment intensity. This study evaluated the effects of gamma rays and ethyl methane sulphonate (EMS) on two sunflower genotypes, DRSF-108 and DRSF-113, in the M₁ and M₂ generations. Dry seeds were exposed to 200, 300, and 400 Gy gamma irradiation, while EMS treatments were applied at 0.1, 0.2, and 0.3%; untreated seeds served as the control. Field germination, plant survival, lethality, and pollen sterility were assessed. In both genotypes, increasing gamma-ray and EMS treatments generally reduced germination and plant survival and increased lethality and pollen sterility. In the M₁ generation, the lowest field germination values occurred at 400 Gy and 0.3% EMS, with DRSF-108 recording 41.11% and 38.88%, respectively, and DRSF-113 recording 39.44% and 38.33%, respectively. Across the mutagenic treatments, M₂ germination and plant survival were higher and lethality was lower than in M₁, while pollen sterility was lower under most treatments. The 200 Gy and 0.1% EMS treatments were comparatively less injurious, whereas 400 Gy and 0.3% EMS caused the greatest biological damage. Among the EMS concentrations evaluated, 0.1% EMS provided the most favourable balance between induced variability and limited biological injury. These results support the further evaluation of surviving M₂ mutant populations for sunflower improvement.