Influence de différents traitements de prégermination des graines de Vigna unguiculata (L.) Walp. sur les performances germinatives et la tolérance au stress hydrique

Influence of different pre-germination treatments of Vigna unguiculata (L.) Walp. seeds on germination performance and water stress tolerance. Description of the subject. Priming or hardening is a pregermination treatment. This treatment consists of incorporating an osmotic seed treatment (osmopriming) or a hormonal (hormopriming) and/or a redehydration (hydropriming) treatment. The approach allows the elimination of dormancy, homogenization (synchronization) of germination, better growth, earlier flowering and a tolerance to abiotic stresses such as drought and salinity. In this kind of treatment, the seed is soaked and then dehydrated before radicle breakthrough, i.e. during the reversible phase of germination. Thus, the seed can return to its initial stage without any damage. Objectives. In this paper, we aimed to study the consequences of hydropriming and osmopriming (by PEG6000 at 10 and 30%) on cowpea seeds (Vigna unguiculata), on germination performance and on the water stress tolerance of plants from these seeds. Method. Vigna unguiculata seeds were hydroprimed, hydroprimed twice or osmoprimed (with PEG6000 10 and 30%). For each treatment, germination performance (germination capacity, speed) and the water stress tolerance of the plants were studied. Results. Results showed that increased hardness of the seed allowed a faster, more uniform germination and better growth of both the radicle and aerial parts. We also demonstrated that a double redehydration was more effective in improving these parameters. Conclusions. Application of these pretreatments, adapted according to the plant species, will has the capacity to improve seed germination and crop yield, as well as tolerance to water deficit