Current Importance and Potential Use of Low Doses of Gamma Radiation in Forest Species

It is well known that ionizing radiation is currently a very important way to create genetic variability that is not exists in nature or that is not available to the breeder (Ahloowalia & Maluszynski, 2001; Lemus et al., 2002). Therefore, there are many papers aimed to determine the best radiation dose to applied in plant breeding work. As a result it has been defined intervals gamma radiation useful for many cultivated species, though the determination of the radiosensitivity of tissues by exposure to different intensities of radiation (De la Fe et al., 1996; Castillo et al., 1997; Fuchs et al., 2002; Lemus et al., 2002; Fuentes et al., 2004; Ramírez et al., 2006). However, most studies have been conducted have been designed to evaluate the biological response to high doses of radiation, while in relatively few studies have used low doses to stimulate physiological processes (radiostimulation) although the ionizing radiation hormesis has been widely supported (Luckey, 1980). Hormesis is the excitation, or stimulation, by small doses of any agent in any sistem (Luckey, 2003). The beneficial effect of hormesis has been well documented in species of agricultural importance (Zaka et al., 2004; Kim et al., 2005). However, there is not enough information about its use in forestry. Although little is known about the basic nature of this phenomenon, Vaiserman (2010) had indicated the possible relationship between the hormesis and epigenetic effects. The application of low-dose ionizing radiation could produce in coniferous species hormetics radiostimulants effects through genetic and epigenetic changes that manifest as adaptive responses.