Genetic analysis of cadmium tolerance and exploration of its inheritance nature in bread wheat (Triticum aestivum L.)

Abstract

Cadmium (Cd) is a non-essential and extremely toxic element that destructively impacts agricultural production. Accordingly, developing Cd-tolerant genotypes with low-grain Cd is a promising approach to cope with the pollution problem. The current study aimed to understand the inheritance nature of Cd tolerance and the detection of Cd-tolerant bread wheat genotypes with low-grain Cd. 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, the realized F1s were selfed to produce F2 populations, and F1s were backcrossed with their own parents to produce B1 and B2 populations. Six populations for each cross comprised P1, P2, F1, F2, B1 and B2 were evaluated in two adjacent experiments under non-Cd stress and Cd-stress conditions. Significant positive relative and standard heterosis were detected for flag leaf area, leaf chlorophyll content, proline content, Cd content and grain yield/plant under Cd-stress conditions. Desirable heterosis was assigned for Cd content, proline content and yield traits in the 1st and 2nd crosses under Cd-stress conditions. These crosses produced higher grain yield while accumulating lower amounts of Cd in grains under Cd-stress conditions. Furthermore, prediction results revealed high transgressive segregates and exceeding F1 with best-inbred lines with favorable alleles obtained from 1st and 2nd crosses for high-yielding and low Cd content under Cd-stress conditions. Both additive and dominance gene effects were involved in controlling Cd content, proline content,and yield traits