Maize landraces as useful donors of genetic diversity for resilience to drought

Releasing maize varieties with greater drought resilience could help to mitigate the effects of climate change. However, continuous breeding gains are constrained by the low genetic diversity of maize varieties used in the past and current breeding programs. The integration of underutilized landraces within breeding programs has the potential to catalyze advances in resilience to drought, whilst concurrently contribute to the mitigation of genetic erosion. Consequently, the present study involves the evaluation of 51 landraces under contrasting environmental conditions, encompassing both humid Atlantic and dry continental climates, and employing diverse water management strategies. The objectives of the study were: first, to characterize the agronomic performance, stability, and adaptation to specific conditions of the landrace panel, and second, to identify potential landrace donors to be crossed to elite inbreds in order to generate base materials for selection programs specific to particular environments. A multiplicative site regression model was employed to visualize the performance of landraces across various environments, thereby facilitating interpretations in terms of mean performance and stability. A total of seven landraces demonstrated good performance across diverse environments, as their mean grain yield values did not differ significantly from those of certain commercial hybrids. However, only two of them, namely Zm_00101 and Zm_00125, demonstrated effective adaptation to severe water stress. Consequently, these landraces have the potential to contribute as valuable genetic variants that could enhance the resilience of elite materials to drought conditions. • Valorization of underused maize landraces for reducing genetic erosion • Identification of sources of adaptation and resilience to drought among landraces • Admixture of Central and North American germplasms could be behind resilience