WO2011074804A2

WO2011074804A2 - Method for mass producing miscanthus

Info

Publication number: WO2011074804A2
Application number: PCT/KR2010/008545
Authority: WO
Inventors: Youn Ho Moon; Bon Cheol Koo; Surn The Bark; Young Lok Cha; Seung Hyun Ahn; Sae Jung Suh
Original assignee: Republic Of Korea(Management : Rural Development Administration)
Priority date: 2009-12-18
Filing date: 2010-12-01
Publication date: 2011-06-23
Also published as: KR101093016B1; WO2011074804A3; WO2011074804A9; KR20110070626A

Abstract

Disclosed is a method for mass production or proliferation of miscanthus grass, which is increasingly attractive as a next-generation energy source from both domestic and abroad, as well as creation of a Mischanthus grass field.

Description

METHOD FOR MASS PRODUCING MISCANTHUS

Embodiments of the present invention relate to a method for mass production or proliferation of miscanthus, which is receiving increasing attention as a next-generation energy source both domestically and abroad, as well as creation of a Mischanthus grass field.

Miscanthus grass, more particularly, Miscanthus sinensis var. purpurascens, commonly known as “pampas grass”, is a C4 crop native to East Asia including Korea and has an annual dry stem yield of 30 ton/ha or more, as compared to other non-food energy crops such as switch grass, due to high photosynthetic efficiency. In addition, Miscanthus is a perennial crop and can thus be harvested continuously for 15 to 20 years without plowing and seeding after planting. Miscanthus substantially maintains soil fertility and thus reduces fertilizer consumption, when it is harvested after nutrients in the stems move to the subterranean stems in autumn during which time the stems mature and begin to wither. Further, Miscanthus is an environmentally friendly crop, since it is highly resistant to both disease and insects in natural environments and thus eliminates the necessity of spraying pesticides.

Conventional methods for proliferation of Miscanthus generally include “seed propagation” to breed seeds and “subterranean stem cutting” in which subterranean stems are cut and excavated from a field 2 to 3 years after planting, and the stems are seeded in a main field. Seed propagation is advantageous in that large amounts of seeds can be collected in autumn, thus reducing production costs of plantlets. However, since Miscanthus has a low seed germination rate and is a cross-pollinated plant and an anemophilous flower pollinated by the wind, this plant has different gene types of seeds and exhibits non-uniform growth in a field which was formed by directly sowing seeds of Miscanthus or seeding the same in a seed bed and growing the seeds. Moreover, among various species of Mischanthus grass, M.X. giganteus cannot undergo seed propagation because it is a triploid Mischanthus created by hybridization of a diploid Mischanthus grass (Mischanthus sinensis) and a tetraploid Mischanthus grass (M. sacchariflorus).

For these reasons, studies are being made in foreign nations to prepare seedlings through subterranean stem cutting, as vegetative propagation and thereby create a Miscanthus field. Subterranean stem cutting, in which subterranean stems acting as nutrient-storing organs of Miscanthus are excavated, which was first developed in Denmark. As shown in FIG. 1, in accordance with this method, subterranean stems are cut with a rotary tiller, and the cut subterranean stems are collected with a potato harvester and are then planted in a new field to create Miscanthus field.

FIG. 1 are images illustrating a series of processes in which propagation and creation of Miscanthus field are performed by cutting subterranean stems of Miscanthus in accordance with a method developed in Denmark in 2007. In this figure, A is an image illustrating a process for cutting subterranean stems with a rotary tiller, B is an image illustrating the cut subterranean stems, C is an image illustrating a process of collecting the subterranean stems with a potato harvester, D is an image illustrating a process of seeding the subterranean stems, and E is an image illustrating a new Miscanthus field created after seeding.

However, subterranean stem cutting has a low propagation to an extent in which a growing area is increased by about 50-fold of a propagation bed area, since subterranean stems are harvested once every 2 to 3 years. In addition, when a propagation bed is mounted in a field containing a great amount of gravel or clay, the operation with the rotary tiller is difficult and selection of sandy soil field is required for harvesting efficiency. The cutting of subterranean stems with the rotary tiller causes great damage to buds sprouting from subterranean stems, thus disadvantageously reducing creation of new buds after seeding and increasing plant missing.

The reason for not greatly increasing a Miscanthus growing area to date although Miscanthus is a promising non-food energy crop is that practically applicable and low-cost mass propagation methods have yet to be developed. The present inventors developed a method for producing Miscanthus rooted cuttings by cutting the top of stems, inducing sprouts from the bud of the joint and cutting the stems to produce Miscanthus rooted cuttings, thereby enabling mass-production of Miscanthus young seedlings with high rooting rate and superior seedling properties, thus greatly increasing a Miscanthus growing area within a short period of time and contributing to production of bio-energy.

An aspect of the present invention is to identify formation conditions of cutting slips with the most superior rooting rate and seedlings properties depending on type of cutting slips upon cuttage, mass-production of cutting slips with high rooting rate and superior properties of seedling, and applicability of Miscanthus cottage to various Miscanthus species.

According to a technical concept of the present invention, there is provided a method for producing Miscanthus including: cutting the top of stems of Miscanthus to induce sprouts from the buds of respective joints under the cut parts; preparing cutting slips with the respective joints; and subjecting the cutting slips to cottage to produce seedlings.

Miscanthus before cutting the top of stems thereof may be grown to 10 or more joints.

Also, the joints, from which sprouts are induced, may be in a state in which the sprouts extend from the buds of joints, but new leaves do not spread.

Also, the joints, from which sprouts are induced, may be in a state in which the sprouts extend from the buds of joints and new leaves spread.

According to a technical concept of the present invention, there is provided a method for creating a Miscanthus field by directly cut-planting the cutting slips in a field.

Among Miscanthus species, triploid improved Miscanthus is a crop having the most dry stem number per unit area, which is prepared into high density pellets in EP and US to produce thermal energy. In addition, Miscanthus is attracting attention worldwide as a cellulose-based crop for fermentation into ethanol, a next-generation transportation fuel, and considerable research is underway into production of ethanol using the same. However, in order to extend Miscanthus growing area, the disadvantage of difficult propagation should be overcome. Subterranean stem cutting, as a conventional Miscanthus propagation method, has low propagation efficiency and involves high seedling production costs, thus showing a lower Miscanthus growth area increase, as compared to other energy crops such as switch grass.

The present invention exhibits high propagation efficiency and involves low seedling production costs, thus reducing the share of seeding costs involved in creation of new Miscanthus fields, increasing planting density due to reduced seedling price, and shortening economically harvestable term. When the field satisfies suitable soil requirements, new Miscanthus fields can be readily created by directly cut-planting slips from which sprouts extend. In addition, when novel promising species are developed, they can be rapidly propagated and dispersed, thus providing considerably high industrial availability.

These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 are images illustrating a series of processes in which propagation and creation of Miscanthus fields are performed by cutting subterranean stems of Miscanthus in accordance with a method developed in Denmark in 2007;

FIG. 2 shows comparison results between classified young and mature cutting slips, and initial and late sprout extension cutting slips;

FIG. 3 shows comparison results of young and mature cutting slips, and initial and late sprout extension cutting slips after the cutting slips are subjected to cottage for 14 days;

FIG. 4 is an image comparing sprout extension of buds according to cutting the top of stems;

FIG. 5 is an image illustrating cutting slips harvested from untreated stems and FIG. 6 is an image illustrating cutting slips harvested after cutting the tops of stems.

FIG. 7 is an image comparing growth behaviors of root and sprout (aboveground) of late sprout extension cutting slips of Miscanthus sacchariflorus, improved Miscanthus and Giant Miscanthus type I after cottage for 40 days; and

FIG. 8 is a schematic diagram illustrating a method for mass-producing Miscanthus according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Example 1] Properties of available seedlings

Substances in this example were Miscanthus sacchariflorus, triploid introduced (improved) Miscanthus, and Giant Miscanthus type I (deposit number KCTC 11580BP) as Miscanthus gene sources obtained from the Bio-energy Crop Research Center, National Institute of Crop Science, Agricultural Demonstration Station.

Once Miscanthus had grown to 10 or more joints, the highest part of joints in which the leaf sheaths peel off was cut. As a result, sprouts extend from respective joints under the cut part. Cutting the top of stems aims to induce sprouts to extend from the joints by removing apical dominance.

Miscanthus contained a bud grown into a sprout in each joint. Accordingly, a cutting slip was prepared from each joint of stems by cutting the stems such that the top and bottom of the joints were left to a length of 10 to 15㎝ and 3 to 5㎝, respectively and the total length of cutting slip was thus adjusted to 13 to 15㎝. The prepared cutting slips were classified into young cutting slips, mature cutting slips, initial sprout extension cutting slips and late sprout extension cutting slips.

A cutting slip in which fresh leaf sheaths are left on the joint was referred to as a young cutting slip, a cutting slip in which leaf sheaths wither away or die was referred to as a mature cutting slip, a cutting slip in which sprouts extend from the buds of joint, but new leaves do not completely spread, was referred to as an initial sprout extension cutting slip, and a cutting slip in which sprouts extend from the buds of joint and new leaves spread was referred to as a late sprout extension cutting slip.

The cutting slips thus prepared and classified according to the type were subjected to cuttage at a density of 10×10㎝ such that the joints in which buds or sprouts were adhered to the seed bed formed from a bed soil composed of a mixture of sand and red clay (1:3) were buried to a depth of 3 to 5 cm. After cuttage, the cutting slips were nurtured by adding water daily to keep the bed sufficiently wet. After 14 days, 20 cutting slips of each type were excavated and properties of seedlings such as rooting rate, Rooting number and root length were evaluated. Rooting rate is expressed as a percentage of the number of subjects having roots with a length of 1 mm or higher to total subject number, and the Rooting number and root length were obtained by dividing the total Rooting number and length of subjects by the total subject number, respectively. Sprout number and length as growth properties of aboveground (sprout) were also obtained by dividing the total sprout number and length of subjects by the total subject number, respectively.

Rooting behavior of young and mature cutting slips and initial and late sprouts extension cutting slips was evaluated, after the cutting slips were subjected to cuttage in seed beds for 14 days, and the results thus obtained are shown in Table 1 and FIGS. 2 and 3.

FIGS. 2 and 3 shows comparison results of cutting slips of young and mature cutting slips, and initial and late sprout extension cutting slips after cottage for 14 days.

Table 1

Growth behaviors of root and sprout (aboveground) (cuttage for 14 days)

Type of cutting slip	Rooting rate (%)	Rooting number (n)	Root length (cm)	Sprout number (n)	Sprout length (cm)
Young cutting slip	47	1.9	0.4	1.0	6.5
Mature cutting slip	70	2.9	0.6	1.0	8.7
Initial sprout extension cutting slip	94	5.5	2.4	1.0	20.3
Late sprout extension cutting slip	100	10.0	5.2	1.5	25.0

As can be seen from Table 1, the young and mature cutting slips exhibited rooting rates of 47% and 70%, respectively, while the initial and late sprout extension cutting slips exhibited higher rooting rates of 94% and 100%, respectively. The young and mature cutting slips exhibited rooting numbers of 1.9 and 2.9 and root lengths of 0.4 cm and 0.6 cm, respectively, which means that the young and mature cutting slips exhibited poor rooting behavior. On the other hand, the initial and late sprout extension cutting slips exhibited rooting numbers of 5.5 and 10 and root lengths of 2.4 cm and 5.2 cm, respectively, which means that the initial and late sprout extension cutting slips exhibited good root growth behavior. The young and mature cutting slips exhibited sprout lengths of 6.5 cm and 8.7 cm, respectively, while the initial and late sprout extension cutting slips exhibited sprout lengths of 20.3 cm and 25.0 cm, respectively, which means that the initial and late sprout extension cutting slips exhibited superior seedling properties.

[Example 2] Sprout extension promotion method

In order to obtain sprout extension cutting slips with superior rooting rate and seedling properties, effects of cutting of apical stems on extension of sprouts from joints were evaluated. When Miscanthus grows to 10 or more joints, the leaf sheaths at respective joints thereof naturally peeled away and the top of the highest joint in which the leaf sheaths peel was cut. After 2 weeks, 20 top-cut stems and 20 natural stems were collected and the number of initial and late sprout extension cutting slips thereof was evaluated.

In order to obtain sprout extension cutting slips with high rooting rate and superior seedling properties, the stems in which the top of joints in which the leaf sheaths die was cut and 14 days passed over were compared with natural stems in terms of sprout extension cutting slip number. Results thus obtained are shown in FIGS. 4, 5 and 6 and Table 2.

FIG. 4 is an image comparing sprout extension of buds according to cutting the top of stems. FIG. 5 is an image illustrating cutting slips harvested from untreated stems. FIG. 6 is an image illustrating cutting slips harvested after cutting the top of stems.

Table 2

Number of sprout extension cutting slips per plant according to cutting the top of stems (n/plant)

Treatment type	Initial sprout extension cutting slip	Late sprout extension cutting slip	Total
No treatment
	1	0	1
Cutting of the top	2	4	6

As can be seen from Table 2, one sprout extension cutting slip was obtained per plant from the untreated stem in which the top is not cut, while six sprout extension cutting slips were obtained from the stem whose top was cut. This demonstrates that the top cutting increases sprout extension cutting slips.

[Example 3] Response of respective Miscanthus species to cottage

In order to identify applicability of cottage techniques established by the inventors to various Miscanthus species, late sprout extension cutting slips of Miscanthus sacchariflorus (tetraploid), indigenous to Korean swamps, improved Miscanthus (Miscanthus X giganteus, triploid) cultivated as an energy crop in foreign nations, and Giant Miscanthus type I were subjected to cuttage for 40 days in the same manner as in Example 2 and root behaviors were then evaluated.

The comparison results of growth behavior of root and sprout (aboveground) after cottage for 40 days are shown in FIG. 7 and Table 3.

Table 3

Growth behaviors of root and sprout (aboveground) of late sprout extension cutting slips for various Miscanthus species (cuttage for 40 days)

Miscanthus species	Rooting rate (%)	Rooting number (n)	Root length (cm)	Sprout number (n)	Sprout length (cm)
Giant Miscanthus type I (tetraploid)	100	16	11.7	5	54
Improved Miscanthus (triploid)	100	14	12.1	5	51
Miscanthus sacchariflorus (tetraploid)	100	13	13.9	5	41

As can be seen from Table 2, there was no difference between improved Miscanthus, Miscanthus sacchariflorus, and Giant Miscanthus type 1 in that improved Miscanthus and Miscanthus sacchariflorus had a rooting rate of 100% and exhibited superior rooting behavior such as rooting number and root length.

Accordingly, stem cuttage for mass-producing Miscanthus is believed to be applicable to propagation of improved Miscanthus, which exhibits high dry stem yield, but cannot propagate seeds as well as Giant Miscanthus type I and Miscanthus sacchariflorus.

As can be seen from Table 4, the number of seedlings produced per propagation bed area, obtained from the mass-production technique via stem cuttage of Miscanthus according to the present invention, was 1,020/m² which is even higher than the number (50-100/m²) of the subterranean stem cutting. When new Miscanthus fields are currently created in foreign nations such as the US, the planting density of seedlings is 100×100 cm². Accordingly, a new field with an area of 50 to 100 m² can be formed with seedlings obtained from a propagation bed with an area of 1 m² by subterranean stem cutting. On the other hand, propagation using the cottage method according to the present invention enables creation of new fields with an even wider area of 1,020 m².

Table 4

Comparison of mass-production of Miscanthus by stem cottage (the present invention) and subterranean stem cutting (prior art) in terms of propagation efficiency

Propagation method	Number of seedlings produced per propagation bed area (n/m2)	Potential planting area (m2)	Note
Subterranean stem cutting	50-100	50~100	Biennial or triennial production
Cuttage	1,020	1,020	Annual production

※ Propagation efficiency calculation

Subterranean stem cutting: Lewandowski, et. al. (2000). Miscanthus: European experience with a novel energy crop. Biomass and Bioenergy 19:209-227

Cuttage: 170 plants/m² (investigation grade of spontaneous land stem density) × 6 stems per plant (see Table 2) = 1,020

Potential planting area: based on the plating density of 100×100 cm²

In addition, although subterranean stem cutting utilizes a sandy soil field in order to improve harvest efficiency, the present invention may utilize a gravel-containing soil or viscous soil as a field for collecting cutting slips and aboveground stems, thus allowing cutting slips to be harvested and propagated on an annual basis. Subterranean stem cutting utilizes a rotary tiller to cut subterranean stems during harvesting of seedlings, thus causing serious damage to buds of subterranean stems grown into sprouts, but eliminating the necessity of using a rotary tiller and preventing damage to buds.

Subterranean stem cutting has low propagation efficiency and inevitably involves low planting density in order to save seedlings when new fields are created. For this reason, the number of stems produced at the beginning of field creation is small and an economically harvestable term is lengthened 3 years. However, mass-production of Miscanthus via stem cottage increases planting density due to high propagation efficiency, thus generating more stems even at the beginning of field creation and shortening economically harvestable term.

Although a few embodiments of the present invention have been shown and described in conjunction with accompanying drawings, it is clearly understood that the foregoing embodiments do not particularly restrict the scope of the present invention. Accordingly, it would be appreciated by those skilled in the art that various substitutions, variations and/or modifications may be made in these embodiments without departing from the principles and spirit of the invention.

Claims

A method for producing Miscanthus comprising:

cutting the top of Miscanthus stems to induce sprouts from the buds of respective joints under the cut part;

preparing cutting slips with the respective joints; and

subjecting the cutting slips to cuttage to produce seedlings.
The method according to claim 1, wherein Miscanthus before cutting the top of stems thereof is Miscanthus grown to 10 or more joints.
The method according to claim 1, wherein the joints from which sprouts are induced are in a state in which the sprouts extend from the buds of joints, but new leaves do not spread.
The method according to claim 1, wherein the joints from which sprouts are induced are in a state in which the sprouts extend from the buds of joints and new leaves spread.
A method for creating a Miscanthus field by directly cut-planting the cutting slips according to claim 1 in a field.