Improvement of tropical and subtropical fruit trees: tangerine, pummelo in Thailand through induced mutation and biotechnology.

摘要

Acute and chronic gamma irradiations for mutation induction in tangerine (C. reliculata) and pummelo (C. grandis) were studied to produce new cultivars with seedless or less seed by using cultured shoot and root from seeds, scions and pot plants. These experiments were conducted at Gamma Irradiation Service and Nuclear Technology Research Center, Horticulture Research Institute, Phichit and Phrae Horticultural Research Center between 2000 and 2006. The results showed that the optimum medium are MS+BA 2 mg L-1 for shoot induction and MS+BA 2 mg L-1 (half) for root induction. Irradiation with Chronic 0, 4, 8, 12, 16, 20 and 24 Krad of gamma rays and Acute 0, 4, 6 and 8 Krad of gamma rays were treated and later, they were irradiated one more time. The M1V0 were developed to be M1V4 in the MS+BA 2 mg L-1 medium. After that, the plantlets (M1V4) were transplanted to pots and will be planted in the field for further selection. The scions which were treated by acute and chronic irradiation were budded on rootstocks and on mature plants and also, the irradiated pot plants were planted in the field at Phichit and Phrae HRC. The cutting back technique was used to develop M1V0 to M1V4. After that, the fruit quality and seedlessness of these plants were investigated. It was found that 2 M1V4 'Khao Thong Di' pummelo which were treated with gamma rays by chronic irradiation with 9.51 and 32.45 Krad, have fruits with seedless. Also, 6 M1V3 and 5 M1V4 tangerine plants which were treated with gamma rays by acute irradiation at 4 and 8 Krad, have fruits with less seeds. However, the fruit quality and seedlessness from these plants will be further evaluated for another 1-2 years before release to the farmers.