ESTIMATE THE GENETIC VARIATION AND ENZYMATIC PERFORMANCE OF CALLUSES OF TWO TYPES OF RICE EMBRYOS BY THE INFLUENCE OF SOME CHEMICAL FACTORS

Sciences, University of Baghdad, during the period 2021-2023.Two rice cultivars, black rice and Amber 33, were used for callus induction to study genetic variation.A 10% extract of Citrullus colocynthis fruit was applied at concentrations of 0, 75, 150, and 225 mL L to determine the LD50 (lethal dose for 50% of cells).After measuring the LD50, the callus of both rice cultivars was cultured in media containing varying concentrations of PEG (0, 1.5, 3, 4.5, and 6%).Genetic variations were assessed using RAPD-PCR with the primers 0PB10 and 0PB06.The primers demonstrated differences in the number of bands and their molecular weights.For black rice, the primer 0PB10 at a concentration of 225 mL L produced six bands with a maximum molecular weight of 2800 bp.Similarly, for Amber 33, the same primer at 225 mL L also produced six bands, with the highest molecular weight recorded at 3100 bp.The second primer, for black rice at a concentration of 225 mL L, produced four bands with a maximum molecular weight of 2400 bp.For Amber 33, the same primer at the same concentration resulted in five bands with a maximum molecular weight of 2000 bp.Enzymes SOD, POD, and CAT were also analyzed, showing that the 1.5% PEG concentration yielded the highest enzyme activity values, with SOD, POD, and CAT recorded at 8.47, 4.32, and 9.76, respectively.In contrast, the 6% PEG concentration produced the lowest activity levels for these enzymes, with values of 3.74, 0.95, and 3.98, respectively.