-Sericulture and Silk Research Institute leads sericulture discipline and industry development in dry areas of China. Documentary Source： Propaganda Department of Party Committee Author： Li Xiaochun R

As the birthplace of sericulture in the world, China has a history of sericulture for more than 5,000 years. The poem "Women hold baskets, follow them, and seek soft mulberry" in The Book of Songs (July) and the record of "A house of five acres, a tree with mulberry, fifty people can wear clothes and silks" in Mencius all show the long history of planting mulberry and raising silkworms in China.

The world-famous "Silk Road" is the representative of China’s splendid culture, which has opened a big stage for China’s commercial and cultural exchanges with the world. As the starting point of the Silk Road, Shaanxi is one of the important cradles of sericulture in China. The excavation of Shiquan "Gold-plated Copper Silkworm" witnessed the scale of sericulture industry in southern Shaanxi in Han Dynasty.

On May 16th, Associate Professor Jiao Feng of our school, doctoral students Luo Rongsong, Dai Xuelei and Liu Hui were co-first authors, and professors Qian Yonghua, Jiang Yu and Zhao Aichun of Southwest University were co-authors. The paper "Chromosome-level reference genome and population genomic analysis provide insight into the evolution and improvement of domestic mulberry" was published online in Molecular Plants and officially published as a cover article on July 6th. It was appraised by peers as "another major breakthrough in mulberry research since Southwest University obtained the genome frame map of wild Sichuan mulberry", indicating that sericulture research in our school has reached the world leading level in this field.

Continuation: leading the development of sericulture industry in northern China

In 1950s, the first director Yao Tuan (second from left) and researchers made mulberry clusters.

In 1938, Professor Yao Liu, who had studied in Japan twice, moved to Shaanxi with the Agricultural College of National Northwest United University and merged into Northwest Agricultural College, and set up a sericulture research room as its director, which was the first of its kind in modern sericulture teaching and research in Shaanxi. In 1958, Shaanxi Sericulture Research Institute was established, renamed Shaanxi Sericulture and Silk Research Institute in 1995, and merged with Shaanxi Academy of Agricultural Sciences in 1999.

In the past 82 years, the Institute has carried out scientific research, demonstration and popularization around the innovative utilization of sericulture germplasm resources, the development of practical new technologies and equipment, and the diversified development of sericulture resources, and has made remarkable achievements.

As early as 1980s, the Institute pioneered the selection and utilization of fruit mulberry in China, and cultivated a series of varieties, such as Hongguo No.1, No.2 and No.3, Baiyuwang and Beifanghong, which were extended to more than 20 provinces and cities. Professor Lu Cheng, the chief scientist of the national modern sericulture industrial technology system, commented: "The fruit fragrance of the red fruit series mulberry varieties floats in China." At the same time, Yangling Shengsang Green Food Co., Ltd., a key leading enterprise of agricultural industrialization in Shaanxi Province, has been hatched. At present, the total assets of the enterprise are 450 million yuan, and the annual output value is over 100 million yuan.

In the 21st century, with China’s sericulture industry entering the transition period, according to the idea of "establishing mulberry industry and diversified development", on the basis of the work of the older generation, researcher Su Chao led the team to carry out the research on the ecological function of mulberry and the diversified utilization of mulberry resources, and opened up a new model of ecological mulberry industry with both ecological and economic utilization, which became a demonstration model of sericulture industry in northern Shaanxi and even northern arid and semi-arid areas of China. At present, the ecological mulberry garden in northern Shaanxi has a total area of more than 600,000 mu, reducing soil erosion by about 5 million tons every year.

Su Chao and Jiao Feng carried out mulberry tissue culture experiment.

Mulberry is full of treasures, and the dry weight of crude protein in mulberry leaves is more than 20%. In 2014, the research institute successfully developed mulberry leaves and poria tea, and realized large-scale production in a mulberry health company in Yulin, with an output value of over 100 million yuan. In addition, the research and development of mulberry branches and leaves as goat feed supplements has demonstrated and promoted more than 30,000 in breeding enterprises in northern Shaanxi in recent years, increasing the income by more than 30 million yuan.

In July, 1989, led by the Sericulture and Silk Research Institute, the "Sericulture Breeding Cooperation in Northern Sericulture Areas" was established in eight provinces and nine institutes in northern sericulture areas such as Shaanxi, Shandong, Shanxi, Henan, Xinjiang, Hebei, Liaoning and Ningxia. Since then, the northern sericulture has entered a new stage of joint, cooperation and common development from individual combat. In 1997, it was renamed as "Northern Sericulture Research Cooperation Zone" and has now expanded to 15 sericulture science and education units in 11 provinces. In the past 30 years, the cooperation zone has jointly identified 80 pairs of silkworm varieties (including 19 pairs approved) and identified 48 mulberry varieties in 7 batches (including 17 varieties approved), and has now become the most influential sericulture scientific research cooperation organization in the northern silkworm area and even the whole country.

From "Shaanxi Silkworm No.3" which won the fourth prize of national invention to "Shaanxi Mulberry 305", the first domestic artificial clone autotriploid mulberry variety; From the method of "pair breeding" initiated in China to the highest basic silkworm variety at home and abroad with cocoon shell rate of 30%; From the automatic weighing instrument for scattered eggs of silkworm eggs to the efficient and broad-spectrum disinfectant "Qiang Chloran" for silkworm houses; From the establishment of the largest fruit and mulberry base in Lintong to the addition of the only functional ecological mulberry comprehensive experimental station in northern Shaanxi, the series of innovative achievements made by the sericulture and silk research institute were evaluated by Xiang Zhonghuai, an academician of China Academy of Engineering, as "Shaanxi sericulture discipline organization led the development of sericulture discipline and industry in northern China".

"The breeding of artificial clone autotriploid mulberry variety Shaanxi Sang305 won the first prize of Shaanxi Science and Technology in 2004.

In 2017, the National Sericulture Industry Technology System-Shaanxi Ecological Mulberry Comprehensive Experimental Station was established.

Innovation: Breakthrough progress has been made in basic research of mulberry and practical technology of sericulture.

Shaanxi, as the cradle of Chinese civilization, has the footprints of sericulture development in the mountainous areas of southern Shaanxi, Guanzhong Basin and northern Shaanxi Plateau. In recent years, Silkworm and Silk Research Institute has made great progress in basic research of mulberry and practical technology of sericulture.

In view of the fact that there is a lack of scientific and systematic species classification of mulberry trees with a cultivation history of more than 5,000 years, 132 domestic cultivated mulberry trees (except Guangdong mulberry) were re-sequenced, and it was confirmed that white mulberry, Rusang, Shansang and Mizuho mulberry belong to the same species, that is, white mulberry. Professor Qian Yonghua said that this is the first time to use genome data to clarify the classification of cultivated mulberry species.

The reference genome of the cultivated mulberry "Husang 32" was reported for the first time, and the 28 chromosomes of cultivated mulberry were confirmed to be diploid by cytological and genomic evidence, which solved the mystery of ploidy of cultivated mulberry. It provides an example for the basic research of ploidy of perennial woody plants in the genome era, and has important reference value for the ploidy research of perennial woody plants.

As an excellent cultivated mulberry variety group distributed in Hangjiahu area, Husang has great value to sericulture prosperity and regional economic and social development in this area since the Southern Song Dynasty. However, the study of ancient agricultural history has long been controversial about its origin and evolution, and it lacks experimental evidence to support it. Based on the resequencing analysis of 134 mulberry varieties from China and Japan, the Institute pointed out that Husang is a unique variety branch formed after long-term intense artificial selection, which is mutually confirmed by the palynology research of Songze site and archaeological evidence of Qianshanyang in Xing Wu, and also coincides with the history that the key silk production areas moved to Hangjiahu area since the Song Dynasty, and the high-yield and high-quality Husang varieties were selected, which provided a theoretical basis for solving production problems.

In view of the continuous increase in labor costs, in recent years, the Institute has developed and integrated "light, simple and efficient sericulture production supporting technology", which was listed as the main technology for the development of cocoon and silk industry by Shaanxi Cocoon and Silk Office in 2013. At present, the coverage rate of the whole province is over 70%, and the new benefit is 350 million yuan. "In the past, it took at least two people to help raise a silkworm. Now, with automatic reeling technology, two people can raise 20 silkworms." Chen Zipei, deputy director of the Sericulture Development Service Center in Shiquan County, said.

In 2006, the school and Shiquan County jointly established Shiquan sericulture experimental demonstration base. At that time, Shiquan had 50,000 mu of mulberry fields and 40,000 silkworms a year, and the comprehensive output value of sericulture was less than 100 million yuan. In 2018, there were 100,000 mu of mulberry fields in the county, with 70,000 silkworms raised annually. The total output value of sericulture industry was 1.6 billion yuan, and the comprehensive income of farmers’ sericulture industry was 400 million yuan. The sericulture industry became the leading industry in increasing farmers’ income, rural development, industrial expansion and economic development. Shiquan also became the largest sericulture county in northwest China and the county with the highest technical level of sericulture farmers. The sericulture industry in Shiquan not only achieved double benefits, but also promoted the upgrading and benefit improvement of sericulture industry in Shaanxi.

Persistence: from the persistent love and dedication to the cause.

In the heyday of 1980s, there were more than 170 employees in the research of silkworm and silk. Since then, due to the shrinking of industrial development, the massive loss of scientific and educational personnel, the serious shortage of research funds, and institutional changes, there are only 11 scientific and educational personnel in the research institute, including 9 "post-60s". It is these "only surviving" researchers who never forget the responsibility and mission of developing the traditional sericulture discipline, stick to the sericulture discipline like spring silkworms, and make continuous efforts and forge ahead to rejuvenate the traditional discipline industry.

With the mission of developing China from a big sericulture country to a powerful sericulture country, Jiao Feng, who received double doctorates from Zhejiang University and Tokyo A&M University in Japan, came to the institute as an introduced talent in 2009, but unexpectedly encountered a series of difficulties: the application for the National Natural Fund in forestry discipline was repeatedly rejected, but there was no mulberry application channel under sericulture discipline in animal husbandry discipline; Obstacles in mulberry transgenic technology make it difficult to break through basic research; Hope to carry out genome research, but there has been no experimental conditions and financial support; He is still an associate professor at the age of 53. Mulberry is our choice for silkworm, and we don’t know what silkworm needs. Only by finding out the key genes can we lay the foundation for gene regulation sites and genetic improvement of excellent traits. Jiao Feng tried his best to start the basic research of mulberry. In the past ten years, he carried out cytology and stress biology research on mulberry polyploid, and at the same time investigated and collected information on mulberry cultivars. After the cost of sequencing the third generation of genome was reduced, during the two years of cooperative research with Professor Jiang Yu, he settled down and sat in an office vacated by Jiang Yu, and discussed with Jiang Yu while sequencing and analyzing. Almost all holidays were spent revising papers, sampling and experimenting. With the tenacity of career as a lifelong struggle and the scientific attitude of seeking truth and being pragmatic, Jiao Feng’s paper as the first author was published as a cover article in Molecular Plants, and the classification of cultivated mulberry plants was cracked by using cytological and genomic evidence.

For decades, the researchers of the Institute insisted on conducting investigations in the germination, flowering and fruiting of mulberry trees, and it was time to go to the fields, no matter whether it was hot summer or heavy rain. "Mulberry trees that are all the same in others’ eyes are objects in our view. Only by going down often can we find their different characteristics and lay a good foundation for breeding. " This is also a habit that Su Chao has kept up to now, using off-duty and holidays to go to the fields to find special materials and solve problems in scientific research and production in time.

When the mulberry trees were cut in summer, they were worried that the workers were not standardized in cutting the experimental mulberry trees, which would lead to inaccurate experiments. They took the graduate students into the field and worked for a whole day, which would last for four or five days. On June 1 this year, two comrades suffered from heatstroke because of continuous work.

In order to complete the cross-regional multi-point comparison test of fruit and mulberry varieties, they carried out field tests and investigations again and again in the face of the wind, sand and hot sun. After more than 20 years, they cultivated a fruit and mulberry variety "Hongguo No.2" with high quality and high yield, which is suitable for fresh eating and processing, and passed the variety examination and approval of Shaanxi Provincial Forest Variety Examination and Approval Committee.

Now, in addition to training 20 doctoral and master’s degree students, the Institute undertakes the construction of Shiquan sericulture experimental demonstration base, northern Shaanxi ecological mulberry experimental station, Guanzhong fruit mulberry base and nearly 500 mulberry germplasm resources and 220 domestic silkworm germplasm resources, especially mulberry and domestic silkworm germplasm resources, which have not been supported by special funds for a long time, and must be investigated and raised by special personnel every year. Finding money is also an important task. In the words of Su Chao, director of the Institute, precious varieties cannot be allowed.

Mizhi ecological mulberry experimental park

With the proposal of the "Belt and Road Initiative" in the new era, the sericulture industry has carried a new historical mission.

"sericulture for one day, sericulture for life." Holding the simple belief of "not impetuous, not tossing and complaining", practicing the spirit of "western agriculture" and the spirit of scientists, in order to revitalize China’s sericulture industry, and to continue to make greater achievements in new sericulture disciplines and industries in Shaanxi and even the northwest, the researchers of Sericulture and Silk Research Institute have been working hard for ten years with perseverance and perseverance.