Gamma ray irradiation (Co60) of lulo with and without thorns calluses and seedlings (Solanum quitoense Lam.) produced in vitro

The cultivation of lulo de Castilla (Solanum quitoense Lam.) in Colombia is subject to a series of sanitary problems, which has forced many producers to abandon the crop as a result of the total loss of plantations or to transfer the crop to new areas. It is necessary to implement breeding programs in order to produce varieties that are tolerant to the limiting problems. Since these programs require broad genetic variability in the progenitors, the present study aimed to evaluate the possibility of inducing in vitro variability in explants subjected to different doses of gamma radiation using a Co60 source. The evaluated radiation doses were 0 Gy, 15 Gy, 30 Gy, 45 Gy, and 60 Gy in calluses induced with cotyledonary leaves and in seedlings from in vitro cultures of lulo with and without thorns. The survival and regeneration potential were also evaluated. The calluses were the explants that showed the highest survival, and the lulo seedlings without thorns were the most radiosensitive with a mortality of 100% at a dose of 30 Gy. The lulo seedlings with thorns had 100% mortality at a dose of 45 Gy. The irradiated lulo seedlings with thorns had a greater regeneration capacity than the lulo without thorns, with 1.52 seedling per explant and 1.12 seedling per explant, respectively, and the RAM markers showed genetic variability in all the irradiation treatments.