Conclusions Under this research project improvement of quality, such as seedlessness of fruits for Tangerine (C. reliculata) and pummelo (C. grandis), which contribute ain a noticeable manner to the income generated by agriculture in Thailand was studied using induced mutation and in vitro techniques. The radiation was performed in two sets of experiments: i) Acute irradiation of scions of tangerine viz. Shogun or Sai Nam Puaeng and pummelo viz. Kao Thong Dee at different doses (4-8 krad), and ii) Chronic irradiation of tangerine pot plants viz. Shogun or Sai Nam Pueng and pummelo pot plants viz. Kao Thong Dee at different doses (0.05-0.15 Gy/hr). The scions and/or in vitro derived buds from the treated plants were sub-sequently re-grafted on mature plant until M1V4 for stabilisation of the putative. The optimal media were determined and the protocol carefully described. Some of these irradiated plants were evaluated and confirmed as producing seedless fruits in the field at Pichit and Phare Horticultural Research Center.