The effect of the duration of callus culture on the accumulation of genetic alterations in pea Pisum sativum L.

Two groups of regenerant plants were obtained from different pea genotypes (lines R-9 and W-1 and cultivar Viola). The first group was derived after eight months of culture and the second, from calluses cultured for a prolonged (more than ten years) time. Using random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) methods, the regenerants and the original lines were compared with regard to genetic differences. The regenerants from both groups were shown to differ in DNA polymorphism from the original lines and from one another. The divergence of the regenerants was also different, depending largely on the original genotype. Examination of genetic differences between the first and the second group showed that the variability increased with culturing time. This was particularly evident for regenerants of the Viola cultivar, in which variability ranged from 0–5% (first group of regenerants) to 10% (second group of regenerants).