Using Russian dandelion allelochemicals to elevate disease resistance and improve sugar beet growth

The continuous cropping of sugar beet (Beta vulgaris L.) degrades soil quality, intensifies soil-borne diseases, and substantially reduces yield and quality. Thus, continuous cropping is a serious issue that needs urgent attention. Here, we found that rotation of Taraxacum kok-saghyz Rodin (TKS) with sugar beet increased the diversity of soil microbial community and reduced abundance of pathogenic Fusarium spp., thereby promoting the germination and growth of sugar beet seedlings. Allelochemicals (chemosensory substances) from the roots of TKS were extracted using a heating and stirring ultrasound method. The effects of TKS-RE (T. kok-saghyz-root extracts) allelochemicals on Fusarium spp mycelial growth and spore germination were analyzed. TKS-RE inhibited the growth of F. oxysporum and F. solani. Application of TKS-RE to the roots of sugar beet seedlings increased sugar beet biomass accumulation, activated antioxidant enzymes, increased betaine content, and reduced malondialdehyde content, as compared to the control. The result suggested this rotation of TKS with sugar beet can help establish a better cultivation system to reduce the negative effects of continuous sugar beet cropping and to utilize the advantageous TKS resources.