Effect of recurrent irradiation on the improvement of a variant line of wild tomato (Solanum pimpinellifolium)

Solanum pimpinellifolium L. a breed of wild tomato is rich in lycopene. It possess traits which can be transferred to cultivated varieties. Its fruit size is a major hindirance to its domestication. This breed of tomato is very small and thus this work was carried out to improve the size and other desirable traits of the variety. A variant line, SP 300/30.4.2.4, selected from second generation (M2) following irradiation of seeds of S. pimpinellifolium L. at 300 Gy was used for the work. 2000 seeds were re-irradiated at 150 Gy and 300 Gy for each treatment and nursed immediately. Plant height at first flowering was highest among the control plants reaching a maximum of 47 cm compared to plants irradiated at 150 Gy and 300 Gy which reached 37 cm and 36 cm respectively. Irradiation therefore led to a reduction in plant height of treated plants. Irradiated materials produced bigger fruits than the controls. The highest mean fruit weight recorded for 300 Gy treated plants was higher than those for 150 Gy and the controls. Variations were observed in the fruit size, shape, colour, plant architecture, number of days to 50% fruiting and flowering. The variations observed could be used selected for and used in subsequent breeding work.