Allelopathic effects of Senecio grisebachii L. on seed germination and seedling growth of wheat and barley

We determined the allelopathic effects of aqueous and alkaloid extracts from aerial parts of Senecio grisebachii Baker L., grown in less cultivated and cultivated soils, on seed germination of Triticum aestivum L. (Buck 75 and Baguette 11 cultivars) and Hordeum vulgare L. (Scarlet and Andreia cultivars). The aqueous extracts of S. grisebachii from less cultivated soil showed slight differences in phenolic and flavonoid compounds and higher alkaloid content than plants from the cultivated soil. In plants grown on less cultivated soil the seneciphylline was the major alkaloid followed by senecionine. While in samples from cultivated soil the seneciphylline content was less. The aqueous extracts at 1% concentration from less cultivated soil plants suppressed the seeds germination and seedlings growth in both wheat cultivars, while that from cultivated soil, plants reduced the seed germination and seedlings development of barley cultivar Scarlet. The aqueous and acid base extracts at 1% concentration from the less cultivated soil plants produced similar effects on Andreia cultivar. This is the first study to evaluate the allelopathic interference of S. grisebachii on winter cereals and might be useful to develop new biological strategies to achieve sustainable agriculture.