Yantong SHI, Lin LI, Lin YANG, Zijin NIE

Beijing Agricultural Technology Extension Station, Beijing 100029, China

Abstract [Objectives] To select dandelion varieties suitable for forest land in Beijing suburb plain.[Methods] With the local varieties in Beijing as control, four dandelion varieties, Hebei 2, Shandong 1, Anhui 1 and Henan 1 were introduced, and the growth differences, effective components and yield indexes of different varieties were analyzed. [Results] The leaf and root yield of Henan 1 dandelion was significantly higher than that of the control, and the content of caffeic acid in the root was also higher than the standard of Pharmacopoeia. [Conclusions] On the whole, the dandelion variety Henan 1 is suitable for demonstration planting under the young forest in the plains of Beijing suburb.

Key words Under the forest, Dandelion, Variety, Selection

1 Introduction

Under-forest economy is to carry out a three-dimensional management model of various industries under the forest canopy with the help of the ecological environment of woodland and the use of land resources and shady space under the forest canopy, so as to realize resource sharing, complementary advantages and circular development[1]. The forest-herb planting model is to make use of the time difference and space difference in the growth process of all kinds of plants to allocate them reasonably in horizontal and vertical structure and time, so as to solve the problem of waste of resources caused by large areas of idle land under the forest, so that farmers can obtain income in a relatively short time and increase the output value of woodland[2].

With the advance of the afforestation project in Beijing Plain, a large number of available woodland spaces have emerged. Dandelion (Taraxacummongolicum), a perennial herb in the Compositae family, is one of the medicinal and edible plants stipulated by the National Health Commission[3]. There are more than 2 000 species of dandelion in the world, while there are more than 100 species of dandelion all over China. Fresh dandelion to be eaten has been recorded in many places in China. Because its roots, flowers and leaves contain effective chemical components, it has many pharmacological values, such as cancer resistance, tumor resistance, antioxidation, scavenging free radicals and bacteriostasis[4]. The study shows that certain economic benefits can be obtained by planting dandelion under the young forest[5]. Planting traditional Chinese medicine under the forest can not only produce certain economic benefits, but also produce landscape effects, cover bare land in winter and produce ecological benefits[6]. However, there are few reports on the varieties (lines) which are suitable for planting under the forest. For the problems of single quality, low yield and quality degradation of dandelion under the forest in the suburbs of Beijing, the introduction and screening experiments of different varieties (lines) of dandelion were carried out in order to select the suitable dandelion varieties (lines) for planting under the forest.

2 Materials and methods

2.1 Time and place of the experimentThe field experiment was carried out on the afforestation land in the plain of Caogentang Farm in April 2020. The tree species are four-year-oldRobiniapseudoacacia, the row spacing is 4 m, and the canopy density under the forest is less than 40%.

2.2 Test materials and treatmentFour dandelion varieties (lines) from different producing areas were introduced: Hebei 2, Shandong 1, Anhui 1 and Henan 1. Beijing native dandelion varieties were used as control. Three rows with similar canopy density were selected, using random block arrangement for treatment, with three replicates, each plot area of 10 m2, a total of 15 plots.

2.3 Index determinationStarting from May 25, samples were taken every other month to measure the biomass of leaves and roots of a single plant. The leaves were harvested once in the three vigorous growth periods (July, August and September), and the total root yield of the plot was measured at the end of October. When harvesting, the above-ground part was taken off first, and the fresh weight of the leaves was weighed immediately after removing impurities. After manually extracting the under-ground part, it was brought back to the room to rinse with tap water and then dry to determine the fresh yield of dandelion in the plot. Finally, the sample was placed in a dry and ventilated place to dry naturally, the dry yield was measured according to the plot, and was converted into yield per unit area, kg/ha.

Determination of active component (caffeic acid) content: it was sampled during the harvest period; according to the 2015 edition ofChinesePharmacopoeia, Hebei Xinminhe Quality Inspection Technical Service Co., Ltd. was entrusted to determine the caffeic acid content of different dandelion roots.

2.4 Data analysisThe test data were processed by Excel software and analyzed by SPSS software.

3 Results and analysis

3.1 Comparison of growth differencesThe growth differences of different dandelion varieties under the forest are compared, as shown in Fig.1.

In Fig.1-A, the results showed that the width growth trend of different varieties was basically the same. Before June, dandelion grew slowly, grew rapidly from June to August, reached the peak at the end of September, and then plant width changed slowly until the harvest period stopped. Henan 1 grew rapidly, having the largest plant width. The growth difference of leaf number of different varieties is shown in Fig.1-B. Before September, the leaf number grew rapidly, showing a trend of first increase and then decline. After September, as the temperature became cooler, some leaves withered and the number of leaves decreased. In the period of vigorous growth, the number of leaves per plant of Henan 1 was significantly larger than that of other varieties.

Fig.1 Comparison of growth differences of different dandelion varieties under the forest

3.2 Comparison of active componentsThe comparison of effective components of different varieties (lines) of dandelion under the forest is shown in Table 1. The results showed that the emergence rate of the tested varieties was significantly higher than that of the control, and the emergence rate of Henan 1 was 88%, which was significantly higher than that of other treatments. The results of caffeic acid of the tested varieties showed that the caffeic acid content of the tested varieties was higher than the minimum caffeic acid content stipulated in theChinesePharmacopoeia(>0.02%). Among the tested varieties, the caffeic acid content of Hebei 2 was 0.06%, which was not significantly different from that of the control (0.05%). The caffeic acid content of other varieties was significantly higher than that of the control, and the highest caffeic acid content of Henan 1 was 0.16%, which was significantly higher than that of other varieties.

3.3 Comparison of yieldThe results of yield per unit area (ha) of leaves and roots of different dandelion varieties (lines) under the forest are shown in Table 2. During the peak period of plant growth, fresh leaves were harvested three times. The fresh

Table 1 Comparison of emergence rate and effective components of different dandelion varieties (lines) %

Table 2 Comparison of yield of different dandelion varieties kg/ha

leaf yield of Shandong 1 dandelion was lower than that of the control, and the fresh leaf yield of Hebei 2 dandelion was 12 482.85 kg/ha, which was not significantly different from that of the control. The fresh leaf yield of dandelion Henan 1 was the highest, reaching 16 863.83 kg/ha, which was significantly higher than that of other varieties. In terms of root dry weight, Henan 1 performed better, and its estimated yield reached 2 401.20 kg/ha, which was significantly higher than that of the control.

4 Conclusion

Fresh leaves can be harvested three times in the first year of planting under the forest, and the total yield of the three crops of Henan 1 was 16 863.83 kg/ha, which was higher than that of other varieties; the root dry yield of 2 401.20 kg/ha was significantly higher than that of the control, and the caffeic acid content was higher than the standard of Pharmacopoeia. According to the above indexes, Henan 1 is suitable for planting demonstration under the young forest.