Crop germplasm resources are the genetic material basis for agricultural scientific and technological innovation and variety improvement, and are national strategic resources to ensure the sustainable development of agriculture (Zheng et al., 2011; Liu et al., 2017). China’s agriculture originated in the early Neolithic Age and has a history of more than 9000 years. From north to south, there are cold temperate zone, middle temperate zone, warm temperate zone, subtropical zone, tropical zone and other temperature zones, as well as the special Qinghai Tibet alpine region. The long history, complex terrain and diverse climate have created various farming systems and cultivated rich germplasm resources.

Since the founding of new China, China has carried out two nationwide collection of crop germplasm resources from 1956~1957 and 1979~1983 respectively, conducted special investigation and collection for many times, saved a large number of endangered local varieties and wild germplasm resources, and preserved more than 480 000 germplasm resources, which made great contributions to the development of China’s agriculture (Zeng et al., 2019). Now, with more than 30 years having passed, significant changes have taken place in society, economy, environment and planting structure, especially the rapid development of urbanization and industrialization, resulting in the rapid disappearance of a large number of local varieties and the sharp reduction of wild related species due to the destruction of living environment (Zhang et al., 2018). In order to comprehensively investigate the distribution, evolution and utilization of crop germplasm resources in China, clarify the impact of changes in society, economy, environment and planting structure on the evolution trend of germplasm resources, understand the temporal and spatial distribution of local superior varieties and wild relatives, and local residents’ cognition, protection and utilization of different crop germplasm resources, and in order to increase the quantity and diversity of germplasm resources preserved in China and provide material and technical support for new variety breeding and food security, China officially launched the third national survey and collection of crop germplasm resources in 2015. A comprehensive survey of crop germplasm resources was carried out in 2 228 agricultural counties (cities) in 31 provinces (autonomous regions and municipalities) across the country, and systematic investigation and rescue collection was carried out in 665 agricultural counties (cities) rich in crop germplasm resources. It was estimated that 100 000 germplasm resources would be collected and 70 000 would be stored in the warehouse by 2020 (Liu et al., 2018).

Zhejiang has a land area of 10.1×10⁴ km² and diverse landforms. It is one of the provinces rich in crop germplasm resources. According to the requirements of the Implementation Plan for the Third National Survey and Collection of Crop Germplasm Resources (Nongbanzhong [2015] No.26), Zhejiang Province has carried out the survey and collection of crop germplasm resources in 63 counties (cities and districts) such as Tonglu County, Chun’an County and Huangyan District since April 2017. At the same time, Zhejiang Province has carried out systematic investigation and rescue collection of crop germplasm resources in 19 counties (cities and districts) including Jiande City, Qingyuan County, Kaihua County. And Zhejiang Province plan to collect more than 4 000 copies of ancient local varieties, cultivated varieties with long planting years, and rare and endangered wild related germplasm resources. From 2017 to 2020, Zhejiang Academy of Agricultural Sciences and Agricultural and Rural Bureau of Jingning Shezu Autonomous County organized a comprehensive survey of crop germplasm resources in Jingning Shezu Autonomous County, and basically found out the planting history, species, distribution characteristics and local characteristic germplasm resources of various crops in this area. Through systematic investigation, some excellent germplasm resources were salvaged and collected. Through publicity, people’s awareness of the protection of crop germplasm resources is improved, which provides an important reference for promoting the protection and utilization of crop germplasm resources in Jingning Shezu Autonomous County.

1 Results and Analysis

1.1 Types of germplasm resources

From 2017 to 2020, the investigation team carried out systematic investigation and collection of 6 townships (streets), 12 administrative villages and 35 natural villages in Jingning Shezu Autonomous County, and collected 120 crop germplasm resources (Table 1). According to regional statistics, there were 43 in Shawan Town, 39 in Dajun Township, 13 in Hongxing Street, 10 in Zhengkeng Township, 8 in Hexi Street and 7 in Yingchuan Town. The resources were distributed at an altitude of 196 ~ 1 020 m, involving many kinds of crops such as grain, fruit trees and vegetables.

Table 1 The distribution of crop germplasm resources in Jingning Shezu Autonomous County

74 vegetable resources were collected, including Brassica juncea, Brassica chinensis, Phaseolus vulgaris, Vigna unguiculata, Brassica pekinensis, Lagenaria siceraria and Cucumis sativus. 27 food crops were collected, with Oryza sativa as the most, followed by Hordeum vulgare and Dioscorea esculentac. 11 fruit tree resources were collected, including Pyrus spp, Myrica rubra and Citrus maxima. 8 other crop resources were collected, including Morus alba and Arachis hypogaea.

1.2 Distribution characteristics of crop germplasm resources

Through the investigation of Jingning Shezu Autonomous County, it was found that remote villages with inconvenient transportation and inhabited by ethnic minorities mostly reserve seeds for themselves due to difficulties in purchasing seeds and seedlings, less demand for seeds and national habits. These places are very rich in germplasm resources. Dawan, Zhaihou Village, Yingchuan Town, located in the depths of the mountain, with an altitude of 855 m and only a few elderly people live in, are basically self-sufficient. decades of Diospyros kaki (2018332028), Myrica rubra (2018332031) and hundreds of years of Castanea henryi (2018332035) can be seen everywhere in this village. Wubu Village in Zhengkeng Township is a typical Shezu village. Except for Oryza sativa, Vigna unguiculata (2018332108), Cucumis sativusr (2018332117) and Brassica juncea (2018332111) are local varieties for many years.

In suburban areas, due to convenient transportation and personnel gathering, common grains and vegetables in large farmers’ markets, such as Oryza sativa, Vigna radiata, Brassica pekinensis, Cucumis sativus and Phaseolus vulgaris, are basically excellent varieties in the market. Some of the vegetables and fruits sold in the streets are still planted by the growers themselves, such as Allium fistulosum (2018332004), Laobaicai (2018332007), Wuyacong (2018332038) and so on.

1.3 Identification of some characteristic germplasm resources

1.3.1 Xiaoyumi

Corn (Zea mays) is the third largest food crop in the world, and its planting area in China is also very large. It is mainly used for feed, food and wine making. In recent years, fruit corn has also developed very rapidly, and it is basically a mature commercial variety. The Xiaoyumi (2018332051) found in Dafan, Yanglvhu Village, Hongxing Street, Jingning Shezu Autonomous County has been planted locally for about 70 years, and was introduced from Qiandao Lake area from 1950s to 1960s (Figure 1). The plant height is 200 cm, each plant has 4 ~ 6 ears, and the stem is slightly sweet; The ear is long, rod hammer shaped, and the ear is about 15 cm long; The grain surface is bright red, nearly round, with a diameter of about 0.5 cm; The yield is about 750 kg per mu. It is mainly used as popcorn and corn rice.

1.3.2 Zishanyao

Dioscorea oppositifolia is a plant of Dioscorea genus in the family of dioscoreaceae, also known as yam, Huaishanyao, Tushu, Shanyu. Edible tubers are mostly long cylindrical and white in flesh. Purple varieties were found in Jingning Shezu Autonomous County this time. The tubers are palm shaped, locally known as “Qi” (2018332106). The skin is purple black, while the flesh is purple red, rich in anthocyanins, with a single weight of up to 2 kg. They are used locally as soup, which has the effects of Tonifying the spleen and stomach, benefiting the lung and kidney (Figure 1).

Figure 1 The Xiaoyumi (2018332051) and Qi (2018332106)

1.3.3 Hongmi

Hongmi, also known as Yanzhimi, has a good health care effect. It can remove free radicals, delay aging and improve immunity. It has always been highly praised by people. Six samples of Hongmi were collected in Jingning Shezu Autonomous County (Figure 2): Hongjin (2018332009), Chigujingmi (2018332010), Chipidao (2018332029), Qingyuanhongmi (2018332032), Dajiehuang (2018332033) and Hongmang (2018332034), which have been cultivated in this area for many years. The outer skin of Hongmi is similar to that of ordinary rice. The rice is light red and contains certain anthocyanins. Its rice has good quality, high nutritional value, slight sour taste, light taste, and poor taste when cooked alone. It is generally mixed with commercial varieties for rice porridge or soup, and can also be processed into flavor snacks.

Figure 2 Six collected Hongmi germplasm resources

2 Discussion

In the two national crop germplasm resources surveys conducted 1956~1957 and 1979~1983, 49 germplasm resources were collected in Jingning Shezu Autonomous County and Yunhe County, including 15 Hordeum vulgare, 12 Oryza sativa, 7 Glycine max, 3 Triticum aestivum, 3 Pyrus spp, 3 Boehmeria nivea, 1 Camellia sinensis, 1 Lagenaria siceraria, 1 Azolla filiculoides, 1 Cucurbita moschata, 1 Vigna unguiculata and 1 Sesamum indicum (http://www.cgrchina.cn/#). A total of 120 germplasm resources were collected this time, and the number was higher than the previous two times, mainly due to the large range of crop types collected this time, but many previously collected germplasm resources were rarely found in this survey. Only one Daimai resource (2018332041) was found in this survey, which was planted in Dafan, Yanglvhu Village, Hongxing Street. Other Hordeum vulgare germplasm resources such as Jingning Dalimimai (ZDM03208), Jingning Youfudamai (ZDM03020) and Jingning Changtousizhu (ZDM03209) have been no longer planted locally. In addition, Triticum aestivum germplasm resources such as Heshangmai (ZM006971), Liuleng (ZM006969) and Tiedingmai (ZM006970) and Yeshengdadou (ZYD04460) have also disappeared. Other germplasm resources may have new names or disappeared, so it is necessary to identify the genetic relationship at the morphological and molecular level in the later stage.

Jingning Shezu Autonomous County is rich in crop germplasm resources and has a wide variety of crops, but the planting area of most varieties is very small, and some germplasm resources are gradually disappearing. The main reasons for the disappearance are as follows: (1) with the development of economy and the aggravation of population aging, the population engaged in agriculture has decreased sharply, the germplasm resources can not be inherited and die out gradually; (2) With the progress of agricultural production, the change of planting structure and land management mode, the commercial varieties with high yield and strong disease resistance have been vigorously promoted, the old varieties have degenerated, and the traditional local varieties would naturally decrease; (3) Climate change and the acceleration of economic construction have led to the destruction and sharp reduction of the habitat on which the wild relatives of crops depend.

Crop germplasm resources are national key strategic resources and the basis of breeding work. After years of planting, local varieties have good adaptability or specific uses locally (Chen et al., 2019). Through this general survey and systematic investigation, we basically understood the types, distribution characteristics and regions of germplasm resources in Jingning Shezu Autonomous County, and found and identified a number of excellent local varieties. To identify and evaluate the collected germplasm resources, analyze the genetic relationship and diversity, and clarify the genetic background of these germplasm resources is an important link in the breeding of new crop varieties. Using these germplasm resources with excellent traits and with the help of molecular biological means, we can deeply excavate from the aspects of quality, yield and stress resistance, create new germplasm with prominent target traits and breeding value, and speed up the breeding process (Liu et al., 2020). In addition, we can further study the evolution trend of the interaction between nationality, environment and crop population, clarify the law of the coordination between crop germplasm resources and human society and environment, to provide a basis for effectively carrying out diversity research and protection mechanism of germplasm resources (Tang et al., 2020).

3 Materials and Methods

3.1 Overview of the survey site

Jingning Shezu Autonomous County is a county under the jurisdiction of Lishui City, Zhejiang Province. It is located in the southwest of Zhejiang Province, between 119.1 833°~119.9 666° E and 27.6 500°~28.1 833° N. It belongs to the northern region of low latitude in the eastern hemisphere. The county was originally established in the third year of Jingtai of Ming Dynasty (1452), belonging to Chuzhou Prefecture; The People’s Government of Jingning County was established on May 21, 1949 and incorporated into Lishui County in 1960. In 1962, the former Yunhe County and Jingning County of Lishui County were designated as Yunhe County; In May 1963, Lishui District was re-established, governing Yunhe County (including Jingning); In June 1984, Jingning Shezu Autonomous County was established, which is the only Shezu Autonomous County in China. With a total area of 1 950 square kilometers, the county governs 2 Streets, 4 Towns and 15 Townships. The total population of the county is 171 545, including 18 594 Shezu people, accounting for 10.84% of the total population (http://www.jingning.gov.cn/col/col1376092/index.html).

Jingning Shezu Autonomous County is located in the middle of Donggong mountain range. It belongs to the middle mountain area of southern Zhejiang. The terrain is complex, and the terrain gradually tilts from southwest to northeast. The landform is dominated by deep cutting mountains. Oujiang tributary streams originating from Donggong mountains run through the whole territory from southwest to northeast, dividing the county into north and south parts. There are great differences in altitude in the territory. The highest Dazhen Township is 1020 m above sea level, the lowest Chencun Township is 80 m above sea level, and there are 779 peaks above 1000 meters above sea level in the county.

The northwest and southeast of Jingning Shezu Autonomous County belong to the source of Oujiang River and Feiyun River tributaries respectively. It has a subtropical monsoon climate, warm and humid, with abundant rainfall and four distinct seasons. Due to the complex terrain and great difference in altitude, there is a vertical climate zone. The average temperature of the county is 6.6°C in January, 27.7°C in July and 17.5°C in the year. The annual average frost-free period is 241 d, the annual average precipitation is 1 542.7 mm, the annual sunshine hours are 1 774.4 h, and the annual solar radiation is 102.2 kcal/cm². The climate with four distinct seasons and the Shezu ethnic customs of “building houses in the valley, using thatch to make tile, weaving bamboo to make fence and cutting reed to make door” let Jingning Shezu Autonomous County have bred rich crop germplasm resources.

3.2 Investigation methods

Since Jingning Shezu Autonomous County needs both general survey and systematic investigation, the county has adopted the method of combining census collection and systematic investigation. In 2017, the Seed Station of Agricultural and Rural Bureau of Jingning Shezu Autonomous County established a census team composed of professional and technical personnel to conduct a thorough census throughout the county. Zhejiang Academy of Agricultural Sciences has established a systematic investigation team composed of professional technicians in five different fields, including rice, upland crops, fruit trees, vegetables and comprehensive (mulberry, tea, hemp and green manure). In 2018, they began to carry out systematic investigation and rescue collection in the whole county with the census team of the Agricultural and Rural Bureau of Jingning Shezu Autonomous County.

On the basis of the previous census, the systematic investigation team and the census team selected Shawan Town, Zhengkeng Township, Hongxing Street and other Townships (Streets) with inconvenient transportation, complex terrain and rich resources as the key collection townships. Thanks to the leadership of local agricultural technicians, the investigators conducted careful visits and discussions with germplasm resource growers to fully understand the information of germplasm resources as much as possible. The systematic investigation team members filled in the questionnaire of the Third National Survey and Collection of Crop Germplasm Resources, collected various parts of germplasm resources and took photos, and then preserved the germplasm resources in the appropriate breeding season, according to the requirement of Standards and Specifications of Crop Germplasm Resources (http://www.cgrchina.cn/?page_id=12112).

3.3 Contents of investigation and appraisal

The survey content is mainly based on the questionnaire of the Third National Survey and Collection of Crop Germplasm Resources, which recorded the collection location, variety source, planting history, growth and reproductive habits, growth environment, phenological period, cultivation and management requirements, utilization ways and seed conservation and retention methods of germplasm resources in detail. Based on the specific specificity, advantages, utilization ways and protection measures of farmers’ cognition of planting resources, the outstanding characteristics of high quality, disease resistance, insect resistance, cold resistance, drought resistance, barren resistance and yield of crop germplasm resources were identified according to the Quality Control Specifications of Crop Germplasm Resources.

Authors’ contributions

MLX was the executor of the experimental design and research of this study; MLX, LTB, SJ, LFZ and ZYT were responsible for the investigation, inquiry, registration, photographing, collection and identification of crop germplasm resources; WXX and YJG were responsible for coordinating the investigation of germplasm resources in Jingning Shezu Autonomous County; JGH was the conceiver and person in charge of the project, guiding the experimental design, manuscript writing and revision. All authors read and approved the final manuscript.

Acknowledgments

This study was jointly funded by the Third National Survey and Collection Action of Crop Germplasm Resources - the Project of Species and Variety Resources Protection Fee in China (111721301354052231-2-2) and the Major Special Project for Breeding of New Fruit Variety in the “13^th five-year” Plan of Zhejiang Province (2016C02052).

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