Exploring the role of gamma irradiation in modulating physiological and biochemical traits of dragon fruit (Selenicereus undatus)

Dragon fruit (Selenicereus spp.), known as pitaya or pitahaya, a tropical climbing fruit from the family Cactaceae, is rich in antioxidants, vitamins and fiber. Commercial propagation through stem cuttings limits genetic diversity, hindering cultivar development. However, white-fleshed varieties perform poorly in acidic soils, which restricted the cultivation that necessitated the need of genetic improvement. To exploit the potentiality of gamma irradiation research trial was carried out to study the influence of gamma irradiation at doses of 0, 100, 200, 300, 400 and 500Gy on the germinability, growth, biochemical content and enzyme activity of white-fleshed dragon fruit seedlings. The study reported that untreated seeds demonstrated the highest germinability, mean daily germination, survival percentage and growth rate. Lower irradiation doses (? 200 Gy) had less influence on physiological and growth parameters, while levels ? 400 Gy significantly reduced germination and development; however, irradiation at 302 Gy was identified as the lethal dose (LD50). The maximum total chlorophyll, protein and nutrient attributes were observed in untreated seedlings and moderately increased to 200 Gy, but the concentration declined sharply at higher doses. The study revealed that biochemical markers associated with abiotic stress tolerance traits likes, proline, phenol, flavonoid and antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) were significantly higher at the 200 Gy irradiation level. The findings suggested that gamma irradiation at 200 Gy dose may be ideal for inducing mutagenesis in dragon fruit, promoting abiotic stress tolerance with minimal adverse impact on seedling growth traits and development of abiotic stress tolerant mutant lines.