A high level of genetic purity in crop varieties must be achieved and maintained for agronomic performance, encouraging investment and innovation in plant breeding and ensuring that the improvements in productivity and quality imparted by breeders are delivered to the consumer. Since the success of hybrid seed production is dependent upon the genetic purity of the parental lines, in this study, the experimental F1exp maize hybrid and its parental inbreeds were used as a model system to examine the discriminative power of morphological, biochemical and SSR markers for seed purity assay. The highest number of off-type plants was estimated by morphological markers. According to the comparison of prolamins and albumins banding patterns of parental and derived F1exp seeds, genetic impurities could not be detected. Molecular analysis detected two types of genetic profile irregularity. Beside its use for verifying varieties of maize, report on umc1545 primer pair ability to detect non-specific bands (i.e., off-types), in both the maternal component and F1exp, which is the first report on this issue yet, strongly supports the recommendation of this SSR marker use for more accurate and time-efficient maize hybrids and parental lines genetic pyrity testing.

An effective strategy to address the impacts of climate change on maize involves early planting, which mitigates drought stress during critical growth phases, preventing yield reductions. The research assessed two maize inbred lines (sensitive and tolerant to low temperature) under conditions of waterlogging stress. This is crucial since early sowing often faces both low temperatures and heavy rain. Morphological, biochemical, and molecular responses were recorded after 24 h, 72 h, and 7 days of stress during the growth stage of 5-day-old seedlings. The findings indicated a more pronounced decline in all morphological characteristics in the sensitive line. Both genotypes displayed an increased root-to-shoot ratio, suggesting that the shoots deteriorate more rapidly than the roots. Physiological evaluations demonstrated that the tolerant line was more effective in managing ROS levels compared to the sensitive line. The involvement of H₂O₂ in aerenchyma formation implies that the decreased POD activity and elevated MDA levels observed after seven days may be associated with aerenchyma development in the tolerant line. Genes essential for PSII function revealed that waterlogging adversely affected photosynthesis in the sensitive genotype. In summary, the low-temperature tolerant genotype exhibited significant resilience to waterlogging, indicating potential interaction between the pathways governing these two abiotic stressors.

In temperate regions, early sowing of high nutritive genotypes could support maize production sustainability by avoiding warming-related unfavorable environment conditions during flowering. Seven standard maize (SM) lines and their nine quality protein maize (QPM) counterparts were evaluated for cold tolerance during germination. Cold stress (13°/6 °C) was applied for five days, after a 48 h imbibition period under optimal temperature (25°/22 °C). Germination, physiological parameters, and some primary and secondary metabolites in the seeds were analyzed. No significant differences (p > 0.05) were observed in cold tolerance between SM and QPM. Cold stress significantly reduced germination energy (SM-p < 0.05, QPM-p < 0.001) and physiological traits (p < 0.001), with shoot traits being most severely affected. The potentially high impact of gallic (p < 0.001), protocatechuic (p < 0.05), and p-coumaric (p < 0.001) acids on germination under stress and negative effect of lutein + zeaxhantin and β-cryptoxhantin (p < 0.05) on root length was revealed. Among all lines, L3QPM excelled under stress, with unchanged germination energy and the lowest fold change in vigor indices (0.35 for VI1, 0.45 for VI2). Also, β + γ-tocopherol and gallic and caffeic acids were significantly higher (p < 0.05) compared to its SM original. Lines L1QPM2, L3QPM, and L7QPM, combining improved nutritional quality with high cold tolerance, will be incorporated in further early sowing research and breeding programs.