Germplasm Resources Creation,Selection,Comprehensive Evaluation And Utilization Of Feed Soybean

Soybean(Glycine max(L.)Merr.)is one of the most important oil crops in the world,and it is also an important protein feed resource.In recent years,with the rapid development of my country’s animal husbandry,it has gradually become an important part of my country’s agricultural economic industry.However,the shortage of feed resources also comes along,which seriously restricts the further development of my country’s animal husbandry.China is the world’s largest soybean consumer,more than 85% of it depends on imports.In 2020,the total soybean imports will exceed the 100 million tons mark.The soybean industry is already facing huge potential risks,which are related to the strategic bottom line of my country’s food security.Soybeans were introduced to the United States as forage grass in the early 19 th century,and whole-plant soybeans have long been widely used as high-quality pastures.However,soybeans contain trypsin inhibitors,which may negatively affect the digestive system of animals,limiting their use in animal husbandry.At present,there are few researches on the breeding and cultivation of forage soybean in China.The purpose of this experiment was to breed a new strain with trypsin inhibitor deficiency suitable for cultivation in Heilongjiang area.At the same time,using my country’s rich soybean germplasm resources,the varieties of the southern soybean ecological zone,the Huanghuaihai soybean ecological zone and the northern soybean ecological zone were introduced to the Heilongjiang area.Screening for high feeding value and finding the best harvesting time for whole plant soybeans.Finally,the selected excellent soybean planting resources were used to conduct intercropping mixed silage experiments with silage corn to explore the feasibility of soybean-corn intercropping and the optimal soybeancorn intercropping ratio in mixed silage samples.The main findings of this study were as follows:(1)In this experiment,Hefeng 50,the main soybean variety planted in Heilongjiang Province,was used as the female parent,and Zhonghuang 16,a soybean variety trypsin inhibitor deficiency,was used as the male parent.Through traditional artificial hybridization and molecular assisted breeding techniques,the breeding traits were good.High-generation line was bred as a trypsin inhibitor deficiency with a long growth period.It can avoid the decrease of the nutritional value of the feed caused by soybeans containing trypsin inhibitors,and can also reduce the damage of the digestive system of animals,and improve the utilization rate and safety of soybeans as feed.(2)Through the cross-regional introduction of 18 soybean varieties from different ecological zones,the yield,main feed quality indicators(crude protein,crude fat,acid detergent fiber,neutral detergent fiber,crude ash)were determined.Using the TOPSIS method based on the entropy weight coefficient the comprehensive score of feeding quality of different soybean varieties in each treatment was comprehensively evaluated.the Qihuang 34(QH34)and Nandou 5(ND5)varieties with excellent feed quality and yield were successfully screened out as high-quality feed soybean resources.The new strain with trypsin inhibitor deficiency also had high feed quality and dry matter yield,and had the potential to be used as feed soybean by silage and soybean cake.At the same time,it was concluded that the early stage of bulging grains(R5)was more suitable for mowing the whole soybean plant than the full flowering stage(R2).(3)The maize-soybean intercropping mixed silage experiment of five cultivation modes(three intercropping ratios)was carried out using the soybean varieties QH34 and Jinling 386.The maize-soybean intercropping mixed silage improved yield,feed quality and fermentation performance.Compared with single corn silage or soybean silage,mixed silage increased crude protein content and dry matter content,reduced acid detergent fiber and neutral content.At the same time,mixed silage had a lower p H,lower levels of acetic,propionic and butyric acids,and higher levels of lactic acid than others treatments.In the microbial community,the relative abundance of the genera Lactobacillus and Weissella increased in mixed silages,while undesirable bacteria,such as Clostridium,decreased compared to single soybean silages.Furthermore,among the three mixed silage groups,the group with an intercropping ratio of 1:3 had the lowest p H,the highest lactic acid concentration,and the highest relative abundance of Lactobacillus and Weissella genera.Therefore, maize-soybean mixed silage changed the microbial community and improved feed and fermentation quality,and the optimal intercropping ratio was 1:3.