Implications of rising atmospheric carbon dioxide concentration on seed quality

Regeneration of plants through seed is governed by the ability and rate to germinate, which largely depends on the climatic variables prevailing during pre-harvest (mother plant growth) and post-harvest (processing and storage) stages. Atmospheric carbon dioxide concentration [CO₂] is increasing rapidly and is expected to surpass 550 ppm within this century. Elevated CO₂ (e[CO₂]) is reported to influence the mother plant at morphological, phenological, physiological and biochemical levels across the species. Such changes are expected to alter the quality components of the progeny seeds, which has received very little research attention. This review discusses about the possible implications of e[CO₂] on quality attributes of seed affecting its planting value with much emphasis on seed weight, germination, vigour and its biochemical constituents. Research indicates that the effect of e[CO₂] on seed weight is variable and influenced by the availability of nutrients particularly nitrogen. Likewise, seed germination shows a divergent effect, whereas seed vigour that indicates the strength of a seed usually is compromised under e[CO₂]. It generally alters the balance between tissue carbon and nitrogen content, thus impairs the normal C:N ratio in progeny seed, which eventually impacts the next generation crop. For mitigation, while global breeding efforts focused on elite but narrow gene pool across the crop species shredded some of the ecologically important seed traits, such as thick and dark seed coat in legumes, such traits must be considered in designing breeding programs as they provide resilience to various stresses. We have suggested additional potential mitigation strategies and areas for future research.