Phenotypic Responses Of Cultivated Soybean And Wild Soybean To Different Environmental Stresses

Soybean(Glycine max)is one of the most important oil crops in the world.At present,the demand for soybean in China is increasing year by year,but there is a huge gap between domestic soybean yield and demand.Northeast China,as the main soybean production area in China,is facing the problem of yield reduction caused by climate change and irrational farming.In order to solve this problem,it is of strategic significance for the sustainable development of soybean industry in northeast China to carry out the breeding of new varieties of soybean under stress.The wild soybean(Glycine soja)is a wild relative of cultivated soybean,it is of great value for broadening the genetic basis of soybean breeding and cultivating soybean varieties with repeated crop tolerance.In this study,(1)The effects of different water conditions(normal watering or drought)and nutrient conditions(limitation or addition)on the growth of wild soybean and cultivated soybean were investigated by greenhouse control experiment.(2)The effects of different nutrient conditions(limitation or addition)and weed conditions(no-competition or competition)on growth of wild soybean and cultivated soybean;(3)Effects of different previous crops(maize and soybean)and soil pathogenic microbial stress(sterilized and non-sterilized)on growth of wild soybean and cultivated soybean;The tolerance of cultivated soybean and wild soybean to different environmental stress was compared.The results showed that:(1)Drought stress significantly inhibited the growth of cultivated and wild soybean,and the tolerance of wild soybean to drought was stronger than that of cultivated soybean.This is mainly because the root allocation ratio of wild soybean is much higher than that of cultivated soybean under drought stress.Compared with the normal watering treatment,the specific root length of cultivated soybean decreased by11.2%,while that of wild soybean increased by 7.8%.Nutrient addition decreased the root mass fraction of cultivated soybean and wild soybean,but increased the specific root length.There was no significant difference in phenotypic traits between different soybean cultivars under drought and nutrient stress.(2)Weed competition had significant inhibitory effect on the growth of aboveground part of cultivated and wild soybean.When cultivated soybean and wild soybean were planted separately,nutrient addition could significantly promote their aboveground growth;in the case of weed competition,nutrient addition would inhibit the aboveground growth of cultivated soybean and wild soybean.In addition,Dongsheng 9 soybean is suitable for planting in areas where weeds are difficult to control;The area with reasonable weed control and fertilization is more suitable for planting Hefeng 55 soybean.(3)Soil pathogenic microorganisms introduced by repeated soybean cropping can inhibit the growth of cultivated and wild soybeans.Compared with the sterilization treatment,the total biomass of cultivated soybean decreased by 28.8% under the nonsterilization treatment,while the total biomass of wild soybean decreased only by 1.9%.Compared with cultivated soybean,wild soybean has stronger adaptability to soybean continuous cropping stress by changing root distribution and leaf morphology;It also showed stronger tolerance to soil pathogenic microorganisms.In addition,it is suggested that Dongsheng 9 should be selected for planting in soybean continuous cropping areas;If the cultivation area adopts crop rotation or corn soybean rotation,it is recommended to select Dongsheng 7 and Hefeng 55 soybean varieties for planting.This study explored the differential expression of phenotypic characters between cultivated soybean and wild soybean under common farmland environmental stress;It was found that under different environmental stresses,the performance of wild soybean in biomass allocation and root and leaf plasticity was stronger than that of cultivated soybean.This provides a theoretical basis for obtaining excellent stress resistance traits from wild soybean and cultivating new stress resistant cultivated soybean varieties in the future.Secondly,it has important reference value for the fertilization and weed management in soybean planting,the solution of problems such as continuous cropping and soil diseases,and the selection of soybean varieties.