Genetic Variability among Egyptian Rice Genotypes (Oryza sativa L.) for Their Tolerance to Cadmium

Aim: Heavy metals are significant environmental pollutants. Cadmium (Cd) is a toxic heavy metal and is also known as one of the major environmental pollutants. Therefore, study the germination ability, seedling growth performance and genetic variability of twelve Egyptian rice (Oryza sativa L.) genotypes in response to Cd stress.

Design: Twelve Egyptian rice genotypes are investigated for their tolerance to cadmium stress at seedling stage. Four cadmium chloride concentrations are applied i.e., 0, 0.01, 0.02 and 0.04 mg/ml to the germinated rice seeds. Five traits are studied i.e., germination percentage, germination index, root length, shoot length and root/shoot ratio.

Results: The results show that the most affected trait is root length in response to Cadmium stress, while germination percentage is the lowest affected trait. The studied rice genotypes show highly significant variability in their response to cadmium stress at seedling stage. The most tolerant genotypes are Giza 177 and Giza 178 for germination percentage, under cadmium stress. While, all studied Egyptian rice genotypes are highly sensitive to cadmium stress at high concentrations for all traits.

Conclusion: It can be concluded that, highly genetic variability are observed among studied Egyptian rice genotypes for tolerance to cadmium stress. Moderate tolerance is observed for germination percentage trait, while the most sensitive trait to cadmium stress is root length.