Soil legacy effects of proceeding crops on the growth of wild soybean (Glycine soja) and cultivated soybean (Glycine max)

The proceeding crop affects soybean yield, soybean continuous cropping in particular leads to soil disease and autotoxin, which inhibits growth and reduce yield; therefore it is urgent to find soybean germplasm resistant to continuous cropping.Traditional breeding methods have reached a bottleneck, while wild-related species resources have great potential to provide beneficial alleles for crop improvement. As a related species of cultivated soybean (Glycine max), wild soybean (Glycine soja) is of great value for broadening the genetic basis of soybean breeding and cultivating soybean varieties resistant to continuous cropping.In this greenhouse control experiment, we analyzed the effects of the soil legacy of different proceeding crops (maize and soybean) on the growth of wild soybean and cultivated soybean.The results showed that the soil of soybean continuous cropping significantly inhibited the growth of subsequent wild soybeans and cultivated soybeans.Compared with sterilized soil, non-sterilized soil significantly reduced the biomass of cultivated soybean while had little effect on the biomass of wild soybean, which indicated that soil pathogenic microorganisms played an important role in the damage of soybean continuous cropping.Soil pathogenic microorganisms increased root mass fraction and tended to distribute biomass to belowground, reduced plant photosynthesis and dry matter accumulation rate.Compared with cultivated soybean, wild soybean rapidly adjusted biomass allocation and leaf traits in response to stress caused by the proceeding crop.Our results provides a theoretical basis for obtaining excellent traits of continuous cropping resistance from wild soybean and cultivating new soybean varieties with continuous cropping resistance in the future.