Genetic variation and identification of molecular markers associated with osmotic adjustment-related traits in gamma irradiation-induced mutants of sunflower (Helianthus annuus L.)

摘要

The objectives of the present study were to evaluate the genetic variability and to identify molecular markers associated with osmotic adjustment-related traits among a population of gamma-induced M6 mutants of sunflower grown under two water treatments. The gamma-induced mutants and original line (AS613) were grown under a fully automated mobile rainout shelter. The experiment consisted of a split-plot design with three blocks. The main plot consisted of water treatments (well-watered and water-stressed) and the subplot contained genotypes (AS613 and 31 M6 mutant lines). Water stress was imposed in flower bud formation stage and relative water content (RWC), osmotic potential at full turgor Qi'spj) and osmotic adjustment (OA) were studied under well-watered and water-stressed conditions at the beginning of flowering. A wide range of variation was observed and some mutant lines with higher values than the original line were identified for osmotic adjustment-related traits. This showed the efficiency of gamma irradiation for inducing genetic variation for drought tolerance in sunflower. Marker-trait analysis showed that some AFLP markers were associated with each trait in both, water treatments (stable markers) and some others are specific for a given water treatment. Furthermore, some AFLP markers were associated with more than one trait. The identified markers could be used in marker-based selection programmes for improving drought tolerance in sunflower.