IV. BALKAN AGRICULTURE CONGRESS, Edirne, Turkey, 31 August - 02 September 2022, pp.382
The global warming is threatening today’s agriculture production and water deficiency forces farmers to demand new plant varieties which tolerate drought stress at various plant development stages. The alfalfa (Medicago sativa) is an essential forage crop and has a significant economic importance worldwide due to its invaluable contribution to sustainable agriculture. However, alfalfa is very vulnerable to drought stress at germination and early seedling growth as well as at regrowth stage right after cutting in the planting year. Development of new drought tolerant alfalfa genotypes by using crossbreeding or by screening existing a narrow genetic bases of alfalfa is difficult due to low heritability and quantitative inheritance of drought stress controlled by several genes. Mutation breeding combined with molecular approaches provides new opportunities to developed drought tolerant novel alfalfa genotypes. Therefore, the objectives of the present study were to develop new drought tolerant alfalfa genotypes by in vitro screening of EMS mutagenized M 3 seeds at germination stages in the presence of osmotic stress of 35% PEG 6000 . The root growth assay provided several drought tolerant mutants and some of them were further characterized under water-deficit conditions applied for 24 days after the first cutting at flower bud stage. Drought stress responses of mutants were compared with irrigated and unirrigated control plants at the physiological, morphological, and transcriptional levels. The results revealed that in vitro screening of M 3 seeds was able to determine drought tolerant novel mutants which also tolerated water-deficit conditions after the first cutting at flower bud stage and gave unique mode of action at transcriptional and posttranscriptional levels.