Genetic Analysis of Cadmium Tolerance And Exploring Its Inheritance Nature In Bread Wheat

Cadmium (Cd) is a nonessential and extremely toxic element that destructively impacts agricultural production. Accordingly, developing tolerant-Cd as well as low-grain Cd genotypes is considered a promising approach to cope with the pollution problem. The current study aimed at understanding inheritance nature of Cd tolerance and detect Cd-tolerant and low-grain Cd genotypes in bread wheat. Six parents were selected based on their Cd tolerance and were genotyped using triple-RAPD and ISSR markers to investigate their genetic diversity. The selected parents were crossed and the realized F1s were selfed to produce F2 populations and were backcrossed with their own parents to produce BC1 and BC2 populations. Six populations for each cross comprised P1, P2, F1, F2, BC1 and BC2 were evaluated in two adjacent experiments under non-Cd stressed and Cd-stressed conditions. Significant positive relative and standard heterosis were detected for flag leaf area, leaf chlorophyll content, proline content, Cd concentration and grain yield/plant under Cd-stressed condition. Dominance gene effect was more pronounced in controlling the evaluated traits in most cases. F values coupled with F/√H×D ratio were positive for Cd concentration and Cd sensitivity index in the three crosses under both conditions. Heritability estimates from offspring regression were high (< 50%) for flag leaf area, leaf chlorophyll content, proline content, Cd concentration while, moderately low for grain yield/plant and Cd sensitivity index. Prediction results revealed to high transgressive segregates and exceeding F1 with best-inbred line (P max) that have all favorable alleles were obtained from 3rd cross for flag leaf area, low Cd concentration and Cd sensitivity index under Cd-stressed conditions.