The expression of the ZmDREB2A/2.1S and ZmPP2C genes is a potential marker for the detection of drought-tolerant maize at high planting densities

The efficacy of a breeding program hinges on its ability to swiftly select desirable lines, as the expression of some key genes is a rapid and efficient marker. Although a wide range of genes are involved in water deficit tolerance, their expression is of considerable interest in maize breeding programs. Thus, this research aimed to analyse the expression of several water deficit-related genes in two contrasting maize lines. Two contrasting lines for drought tolerance (L91-T – tolerant and L24-NT – nontolerant) were sown and grown at two densities—60 and 120 thousand plants/hectare. Leaves, stems, and adventitious roots were collected from these plants for the assays. The relative expression of ZmDREB2A/2.1S (LOC732788), ZmPP2C (LOC542176), CAT3 (LOC542370), and SOD (LOC100136885) was analysed through qRT‒PCR. Independent of the density, higher expression of ZmDREB2A/2.1S was observed for the tolerant line for all tissues collected. For ZmPP2C, greater expression was detected in the nontolerant line. The expression of both genes was greater in the leaves of 120 thousand plants/hectare. The expression of antioxidant system genes (CAT and SOD) was greater for the nontolerant line than for the nontolerant line at 120 thousand plants/hectare. In the search for potential markers for maize water deficit tolerance, with correct adaptations and further studies, the expression of ZmDREB2A/2.1S and ZmPP2C may be used for tolerant and nontolerant lines, respectively.