In vivo induction of parthenogenesis using an irradiated pollen technique provides successful results in melon and accelerates breeding by shortening the time for obtaining 100% homozygous lines. Gamma rays (cobalt-60) are usually used for the pollen irradiation, although it is difficult to find a suitable source for irradiation. | Turkish Journal of Agriculture and Forestry Research Article Turk J Agric For (2016) 40: 552-559 © TÜBİTAK doi: Effect of different irradiation sources and doses on haploid embryo induction in Altinbas (Cucumis melo L. var. inodorus) melons Barış DAL, Nebahat SARI, İlknur SOLMAZ* Department of Horticulture, Faculty of Agriculture, Çukurova University, Adana, Turkey Received: Accepted/Published Online: Final Version: Abstract: In vivo induction of parthenogenesis using an irradiated pollen technique provides successful results in melon and accelerates breeding by shortening the time for obtaining 100% homozygous lines. Gamma rays (cobalt-60) are usually used for the pollen irradiation, although it is difficult to find a suitable source for irradiation. Haploid technology is widely used in melon breeding programs, so there is a need to find alternative sources for pollen irradiation. This study was performed to compare the efficiency of different irradiation sources to induce haploid embryos. One dose of cobalt-60 (300 Gy), two different doses (200 Gy and 300 Gy) of cesium-137, and two different doses (200 Gy and 300 Gy) of X-ray were used for the irradiation of melon pollen. All irradiation sources were efficient for fruit set, while the highest fruit set () was obtained from 200 Gy cesium-137 and the lowest () was obtained from 300 Gy X-ray. A total of 2294 haploid embryos were rescued, of which 2052 regenerated into plants. The number of rescued haploid embryos per fruit ranged between (300 Gy cobalt-60) and (200 Gy X-ray). The highest regeneration rate of haploid embryos into plants was (300 Gy cobalt-60) and the lowest was % (200 Gy cesium-137). Key words: Cesium-137, cobalt-60, embryo rescue, haploid plant, X-ray 1. Introduction Haploidization techniques are known to be useful tools in plant breeding. Haploid and doubled .