Effect of Seedling Quality on Growth, Yield and Quality of Angelica sinensis

Ziteng HE, Youhua CAI*, Lianzhen HE, Zongren LI, Shengping HE, Qide DONG, Shenglong HU, Changman LI

1. Qinghai Hufeng Agro-technical Group Co., Ltd., Haidong 810599, China; 2. Qinghai University, Xining 810016, China

Abstract [Objectives] Aiming at the problems of high bolting rate, low yield and poor quality traits in the production of Angelica sinensis in Qinghai Province, this study investigated the effect of seeding quality on the growth, yield and quality of A. sinensis. [Methods] Field experiments were carried out in five aspects, including different seedling shapes, different seedling sizes, different seedling ages, different seedling raising methods, and different seedling sources. The effect of seedling quality on the survival rate, bolting rate, main quality traits (root length, root fresh weight, root head thickness, root head length) and yield of A. sinensis was investigated. [Results] The seedlings, 0.2-0.5 cm in diameter, 100-110-d old, raised from three-year-old provenance in cultivated land by conventional method, were more preferable, and their survival rate was high, bolting rate was low, yield is high, and quality traits performed well. [Conclusions] The seedlings, 0.2-0.5 cm in diameter, 100-110-d old, raised from three-year-old provenance in cultivated land by conventional method, were more preferable, and their survival rate was high, bolting rate was low, yield is high, and quality traits performed well.

Key words Angelica sinensis, Seedling quality, Bolting rate, Quality trait, Yield

1 Introduction

Angelicasinensis(Umbelliferae) is a perennial plant. It can be used as medicine, and can also be used for making tea, with effect of nourishing blood, activating blood circulation, regulating menstruation, relieving pain, relieving blood stasis, lubricating the intestines and enhancing human immunity. Radix Angelica Sinensis may be used in nine out of ten prescriptions, and it is also called "gynecological holy medicine". With the unique advantages in cold climate resources, Qinghai Province has become a latecomer for the production of high-qualityA.sinensis.A.sinensiscultivation has developed rapidly in Qinghai Province in recent years, and the annual planting area reaches 10 000 ha. Qinghai Province has become the second largest planting province ofA.sinensis, second only to Gansu province. However, the seedling breeding technology is seriously lagging behind, and the production and supply of high-quality seedlings is very scarce. The seedlings used in production are basically introduced scatteredly from multiple distributors in Gansu. The seedlings are more diseased, the quality of the seedlings is poor, the bolting rate is high, and the quality is difficult to control. In particular, the bolting rate in the field is generally above 40%, with the highest rate exceeding 70%, affecting the yield and quality of field cultivation to a large extent, seriously affecting farmers’ planting benefits[1]. In this study, field experiments were carried out in five aspects of different seedling shapes, sizes, ages, raising methods, and sources, to explore the effect of seedling quality on the survival rate, bolting rate, quality traits and yield ofA.sinensistransplanted, thereby providing scientific basis for seedling classification in the standardized production and high-yield, high-quality and high-efficiency production ofA.sinensisin Qinghai Province.

2 Materials and methods

2.1 Overview of experimental areaThe experimental site is located in the Agricultural Demonstration Park of Weiyuan Town, Huzhu County, Qinghai Province (the first major production county ofA.sinensisin Qinghai Province), with altitude of 2 500 m, annual average temperature of 3.4 ℃, precipitation of 50 cm, accumulated temperature (≥ 0 ℃) of 220 ℃, sunshine duration of 2 521.7 h, frost-free period of 112 d, and relative humidity of 65%. The experimental soil was chernozem.

2.2 Experimental materialsThe testedA.sinensisseedlings were Mingui No.1 bred in the seedling breeding base of Weiyuan Town, Huzhu County by Qinghai Hufeng Agro-technical Group Co., Ltd., including seedlings of different shapes, different sizes, different ages and different sources and seedlings raised by different methods.

2.3 Experimental design and methods

2.3.1Experimental design. The experiments all adopted a single-factor randomized block design with 3 replicates for each treatment. The area of each plot was 20 m2. There are 3 treatments for seedling shape experiment: straight seedlings, bifurcated seedlings and radish-shaped seedlings. The seedling size experiment had 4 treatments: extra-small seedlings (diameter<0.2 cm), small seedlings (0.2 cm < diameter ≤0.5 cm), medium seedlings (0.5 cm < diameter ≤0.8 cm) and large seedlings (diameter>0.8 cm). There were 6 treatments in the seedling age experiment: 80, 90, 100, 110, 120 and 130-d-old seedlings. In the seeding raising method experiment, two treatments were set up: conventional seedling in cultivated land and greenhouse seedling in winter. The provenance experiment consisted of two treatments: three-year-old seed and two-year-old early bolting seed.

2.3.2Experimental methods. After the previous crop was harvested, the land was ploughed at a depth of 30 cm. Irrigation was carried out in time after the soil thawed in spring. In early April, combined with deep plowing, organic fertilizer (3 000 kg/ha), diammonium phosphate (600 kg/ha) and potassium fertilizer (300 kg/ha) were applied as basal fertilizer. In mid-April, the seedlings were transplanted, at a spacing of 20 cm×25 cm. In each plot, 400 seedlings were retained. During the growth period, artificial weeding was performed three times. In late October,A.sinensiswas dug out.

2.4 Measured items and methods

2.4.1Survival rate. The ungreen plants in each plot were counted separately 20 d after the transplanting, and the survival rate was calculated.

2.4.2Bolting rate. From June 15 to July 20, the number of bolting plants in each plot was investigated once every 5 d. The bolting rate was calculated.

2.4.3Quality traits. A total of 10 representative plants were randomly selected from each plot during digging for examination of quality traits, including root length, root fresh weight, root head thickness and root head length.

2.4.4Yield. During the harvest period, the yield (fresh weight) of each plot was measured after manual digging.

2.5 Data analysisData processing and analysis was performed using WPS Excel 2019 and SPSS 20.0.

3 Results and analysis

3.1 Effect of seedling morphology on growth, yield and quality ofA.sinensisAs shown in Table 1, different seedling shape had no significant effect on the survival rate ofA.sinensisafter transplantation. The average survival rate of the seedlings reached 93.2%. The bolting rate of the bifurcated seedlings was 58.0%, 39.2% higher than that of straight seedlings. There was no significant difference between straight seedlings and radish-shaped seedlings.

Table 1 Effect of seedling shape on growth and yield of Angelica sinensis

The root length of straight seedlings was largest (26.3 cm), 20.6% and 14.8% higher than that of bifurcated seedlings and radish-shaped seedlings, respectively. The single root fresh weight of straight seedling was 193.0 g, 63.8% and 60.7% higher than that of bifurcated seedlings and radish-shaped seedlings. The root head thickness was 7.7 cm, 120.0% and 92.5% higher than that of radish-shaped seedlings and bifurcated seedlings, respectively. The root head length was 4.7 cm, 327.2% and 74.0% higher than that of bifurcated seedlings and radish-shaped seedlings. The effect was extremely significant. It suggests that the main quality traits ofA.sinensisgrowing from straight seedlings performed better.

The yield of straight seedlings was highest, 13 999.5 kg/ha, 30.0% and 21.5% higher than that of bifurcated seedlings and radish-shaped seedlings, respectively (P<0.01). There was no significant difference between radish-shaped seedlings and bifurcated seedlings (P>0.05).

3.2 Effect of seedling size on growth, yield and quality ofA.sinensisThe survival rate of all the seedlings, except the extra-small seedlings, was above 95% (Table 2). The larger the seedling, the higher the bolting rate, and the more significant the effect.

Table 2 Effect of seedling size on growth and yield of Angelica sinensis

Different seedling size had no significant effect on root length. There was no significant difference in single root fresh weight, root head thickness or root head length between small seedlings and medium seedlings, or between extra-small seedlings and large seedlings. The average single root weight of small seedlings and medium seedlings was 139.9 g, increased by 30.0% and 37.6%, respectively compared with that of extra-small seedlings and large seedlings. The average root head thickness was 4.4 cm, 91.3% and 109.5% higher than that of extra-small seedlings and large seedlings. The average root head thickness of small seedlings was 4.3 cm, 72.0% and 13.2% higher than that of extra-small seedlings and large seedlings, respectively. It suggests that the performance of main quality traits ofA.sinensisgrowing from small seedlings and medium seedlings was better.

The yield of the seedlings of different sizes ranked as small seedlings’>medium seedlings’>large seedlings’>extra-small seedlings’. The effect was extremely significant. The yield of small seedlings was the highest, 17 064 kg/ha.

3.3 Effect of seedling age on growth, yield and quality ofA.sinensisTable 3 shows that the survival rate of the 80-d-old seedlings was 83.3%, and that of the seedlings older than 90 d was all above 90%. The older the seedling, the earlier the bolting, and the higher the bolting rate. There was no significant difference in bolting rate among the 80-110-d-old seedlings, with a mean of 15.8%, which was significantly different from that of 120 (15.0% higher) and 130-d-old seedlings (47.8% higher). As shown in Fig.1, the peak of early bolting of 80-d-old seedlings appeared around July 10; the peak of early bolting of 90-d-old seedlings appeared around July 5; the peak of early bolting of 100 and 110-d-old seedlings appeared around June 30; the peak of early bolting of 120-d-old seedlings appeared around June 25; and the 130-d-old seedlings bolted concentratedly around June 20. That is, as the seedling age gradually increased, the peak period of early bolding gradually advanced. The main reason is that the older the seedlings are, the more nutrients of the seedlings will accumulate. Thus, they will grow vigorously after transplanting and bolt sooner.

Table 3 Effect of seedling age on growth and yield of Angelica sinensis

Fig.1 Dynamics in bolting rate of seedlings of different age

Different seedling age had no significant effect on root length. No significant difference was found in root fresh weight among the 100-110-d-old seedlings, with a mean of 172.0 g, 13.7%, 24.8%, 46.0% and 57.6% higher than that of 120, 90, 80 and 130-d-old seedlings, respectively. There was no significant difference between 80 and 130-d-old seedlings. In terms of root head thickness, there was no significant difference among 100-120-d-old seedlings, with a mean of 3.6 cm, 71.4%, 56.5% and 44.0% higher than that of 80, 90 and 130-d-old seedlings, respectively. No significant difference was observed among the 80, 90 and 130-d-old seedlings. There was no significant difference in root head length among 100-110-d-old seedlings, with a mean of 4.6 cm, 142.1%, 58.6%, 84.0% and 130.0% higher than that of 80, 90, 120 and 130-d-old seedlings, respectively. There was no significant difference among the remaining seedlings. It suggests that the performance of main quality traits ofA.sinensisgrowing from 100-110-d-old seedlings was better.

The yield of 100-110-d-old seedlings was highest, 14 731.5 kg/ha, significantly higher than that of seedlings of other age (120 d, 13.2%; 90 d, 24.4%; 80 d, 56.3%; 130 d, 66.8%).

3.4 Effect of seedling raising methods on growth, yield and quality ofA.sinensisAs shown in Table 4, the transplanting survival rate of seedlings raised in cultivated land by conventional method reached 96.5%, while that of seedlings raised in greenhouse in winter was only 61.7%, reduced by 34.8%. The effect was extremely significant. Different seedling raising methods showed little effect on the bolting rate and main quality traits, but showed an extremely significant effect on the yield of the seedlings. The yield of greenhouse seedling in winter was 34.9% lower than that of conventional seedling in cultivated land. This is mainly due to the low survival rate of the seedlings raised in greenhouse in winter.

Table 4 Effect of seedling raise method on growth and yield of Angelica sinensis

3.5 Effect of seedling source on growth, yield and quality ofA.sinensisNo significant difference was found in survival rate between three-year-old provenance and two-year-old early bolting provenance (Table 5). However, the bolting of two-year-old provenance was earlier, and the bolting rate was as high as 74.4%, 61.9% higher than that of three-year-old provenance. The effect was extremely significant. The root fresh weight, root head thickness and root head length of three-year-old provenance was 83.2%, 28.3% and 24.0% higher than that of two-year-old early bolting provenance, respectively. The performance of main quality traits was better. As the bolting rate of two-year-old early bolting provenance was too high, its yield was significantly lower than that of three-year-old provenance, reduced by 39.9%.

Table 5 Effect of different provenances on growth and yield of Angelica sinensis

4 Discussion and conclusions

High-quality seedlings are the basic guarantee for the quality and yield of medicinal materials[2]. Artificial cultivation ofA.sinensisgenerally adopts seed sowing and seedling transplanting. Therefore, the quality of seedlings has a direct impact on the yield and quality ofA.sinensisafter transplantation[3]. This study shows that seedling quality has a significant effect on the bolting, main quality traits and yield ofA.sinensis.

In terms of seedling shape, the bolting rate of straight seedlings was lower, but their root length, single root fresh weight, root head thickness and root head length were all significantly higher than those of bifurcated seedlings and radish-shaped seedlings. The quality traits of straight seedlings performed better, and their yield was higher. Different seedling shape had no significant effect on survival rate.

Considering the size of seedling, the larger the seedlings, the higher the bolting rate. Seeding size had an extremely significant effect on the bolting rate ofA.sinensis. The bolting rate of small seedlings (0.2 cm0.8 cm) was as high as 80.1%. When the seedlings are too large, the bolting rate will be higher. In addition, the growth potential of the large seedlings in the late growth period is relatively weak, which affects the root growth of the later period, resulting in a relatively low yield[4].

From the perspective of seedling age, the older the seedling, the higher the post-transplanting survival rate, the earlier the bolting, and the higher the bolting rate. The survival rate of the seedlings older than 90 d was all above 90%. The average bolting rate of 80-110-d-old seedlings was 15.8%, 15.0% and 47.8% higher than that of 120 and 130-d-old seedlings, respectively. As the seedling age increased, the peak of early bolting was also significantly earlier. That is, the older the seedling, the more nutrients that will be accumulated, the more vigorous the growth, and the earlier the bolting. The performance of quality traits of 100-110-d-old seedlings was better, and their yield was higher.

The post-transplanting survival rate of seedlings raised in greenhouse in winter was significantly lower, only 61.7%, 34.8% lower than that of the seedlings raised in cultivated land by conventional method. The yield of greenhouse seedlings was 34.9% lower than that of conventional seedlings. It indicates that the effect is extremely significant.

The bolting rate of two-year-old early bolting provenance was as high as 74.4%, 61.9% higher than that of three-year-old provenance. The quality traits and yield were obviously poor, with a yield reduction rate of 39.9%.

Considering comprehensively, in the field production ofA.sinensis, straight seedlings, 0.2-0.5 cm in diameter, 100-110-d-old, raised from three-year-old provenance in cultivated land by conventional method are more preferable, and their survival rate is high, bolting rate is low, yield is high, and quality traits perform better, significantly improving the yield and quality, increasing the output of first-class Radix Angelicae Sinensis. It is one of the most basic and effective measures to achieve high-yield, high-quality and efficient production ofA.sinensis.

The Chinese version of this paper is published inSeed[2020, 39(11), 103-106].