Conventional and Molecular Improvement of Maize for Drought Tolerance: Research Review

Maize (Zea mays L.) is an important staple crop for food, feed, and industry globally. Despite the importance of maize as a principal food crop in developing countries, drought is a major constraint that affects maize production, particularly in Sub-Saharan Africa, where maize is grown under rainfed conditions. Plant breeders have been striving to improve and develop drought-tolerant crops. Nevertheless, these efforts still cannot meet the demand for food security due to fast population growth and climatic change. Conventional maize breeding for drought tolerance follows a diverse approach that includes recurrent selection, backcrossing, pedigree breeding, and subsequently evaluating inbred lines and hybrids at optimum conditions, a managed screening site, and random stress across multiple environments. Molecular markers were used to select donor parents with drought-adaptive alleles and then integrated into elite maize lines to create a new population of drought-tolerant inbred lines.