JPH05153864A - Method for culturing paddy-rice plant - Google Patents

Abstract

PURPOSE:To carry out culture of a paddy-rice plant while promoting growth of a paddy-rice plant and suppressing occurrence of diseases by applying a VA mycorrhizal fungi to the paddy-rice plant when the paddy-rice plant is cultured and culturing the plant under aerobic conditions. CONSTITUTION:A VA mycorrhizal fungi, e.g. preferably Scutellospora gregaria or Glomus fasciculatum is previously mixed in soil and a paddy-rice plant is sowed in the soil and cultured while keeping the seedling raising soil in aerobic condition of >=100mV oxidation-reduction potential.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cultivating paddy rice, and more particularly to a method for promoting the growth of paddy rice and cultivating healthy seedlings by applying VA mycorrhizal fungi to the rice to cultivate it.

[0002]

2. Description of the Related Art Paddy rice has a limited period of rice planting due to factors such as temperature and harvest time of previous crops. For this reason, it is necessary to raise seedlings at the timing of rice planting, and if the seedlings are delayed, they are likely to be affected by cold damage and typhoons. Therefore, promotion of the growth of paddy rice seedlings and raising healthy seedlings are important issues.

On the other hand, VA mycorrhizal fungi have long been known to be useful, such as infecting many plants, promoting the growth of the plants, improving disease resistance, and the like. However, V
Although it is known that mycorrhizal fungus infects upland rice, it is a common theory that it does not infect rice, and there has been no report that it infects rice.

As described above, the reason why VA mycorrhizal fungi are considered to be unlikely to infect aquatic plants such as paddy rice is that phosphorus, potassium, Can easily absorb nutrients such as nitrogen from the roots, and the environment of roots such as rice fields, swamps and riverbeds can easily become anaerobic,
It is not preferable for VA mycorrhizal fungi. However, the reason why it is difficult for VA mycorrhizal fungi to infect paddy rice is considered to be due to the cultivation method of paddy rice, not to the crop itself. If it is possible to infect paddy rice with VA mycorrhizal fungi, not only can paddy rice be cultivated more efficiently than in the past, but the yield of rice can be increased as a result.

Based on the above idea, the present invention has conducted extensive studies on a method for efficiently infecting paddy rice with VA mycorrhizal fungus, and as a result, depending on the environmental conditions for infection with VA mycorrhizal fungus,
The inventors have found that this problem can be solved, and have completed the present invention based on this finding.

[0006]

That is, the present invention provides a method for cultivating paddy rice, which comprises applying VA mycorrhizal fungi to the paddy rice and cultivating it under aerobic conditions. To do.

VA mycorrhizal fungus is a kind of zygomycete existing in soil, and it is known that its hyphae form mycorrhizal roots of various plant roots and both of them coexist. There are various types of VA mycorrhizal fungi used in the present invention, for example, genus Scutellospora, Glomus (Glo).
mus, Gigasora, Acaurospora (Aca)
ulospora), Sclerocystis,
There are microorganisms belonging to the genus Entrophospora. Above all, Scutellospo
VA mycorrhizal fungi belonging to the genus ra), the genus Glomus, the genus Gigasora and the like are preferable.

Concretely, as such VA mycorrhizal fungi,
For example Scutellospora gre
garia), Glomus intrarradices (Glomus intrar
adi-cies), Glomus fasciculator
sciculatum), Glomus mosseae, Glomus etunicatum, Glomus
Caledonium (Glomus caledonium), Gigaspora margarita, Akaurospora laevis
(Acaulospora laevis), Enterophospora infrequens, and Sclerocystis dussii.

These VA mycorrhizal fungi are collected from the natural world (Tatsuhiko Suzuki, Problems on VA mycorrhiza 5, Agriculture and Horticulture, Vol. 62, No. 3, p28-33, 1987) and others.
Nutrient thin film culture method (Japanese Patent Laid-Open No. 55-118390) or method using organ-cultured root (Japanese Patent Publication No. 62-4903).
No. 7, etc.) and the like can be used. In addition, Gromus Intraradices is a US NP
Sold by Company I as Nutri-Link (trademark). Moreover, what attached the VA mycorrhizal fungus to the inorganic substance or organic substance of a carrier (0.5-5 mm) grade can also be used as a VA mycorrhizal fungus.

The variety of paddy rice to be infected with VA mycorrhizal fungi is not limited, but varieties such as Sasanishiki, Hitomebore and Koshihikari are preferable.

Next, there is no special condition for the method of applying VA mycorrhizal fungus to paddy rice, and the application time may be before or after rooting of the paddy rice, but it is particularly preferably applied at the time of sowing. As an application method, it is preferable to mix with the soil or to apply it in a layered form to the lower layer of the seed.

Since the period for raising seedlings of paddy rice is usually as short as 20 to 30 days, VA should be infected with VA mycorrhizal fungi immediately after rooting.
It is also a good method to mix mycorrhizal fungi in the soil beforehand. The amount of VA mycorrhizal fungi applied to paddy rice may be such that paddy rice can be infected, but it is usually 500 per 1 nursery box.
˜50,000, preferably 2,000 to 10,000 spores may be administered.

As described above, the cultivation of paddy rice is required to maintain an aerobic environment, and the conventional method of using paddy rice seedlings is not preferable because it tends to be anaerobic.
A method using a nursery box having high air permeability is preferable. The aerobic condition in this case is such that the redox potential in the nursery soil filled in the nursery box is -100 mV or higher, preferably -50 mV. The temperature is 10 ° C or higher, preferably 15 to 35 ° C.
Is.

Further, with respect to the fertilizer, it is not necessary to give it because the fertilizer is usually sufficiently added to the commercially available seedling soil for paddy rice. When using homemade soil,
It is important to avoid over-fertilization, especially over-supply of phosphorus. In addition, a fungicide is often used to prevent the damage caused by mold during seedling raising, but captan, demosane, manneb, sodium azide, lidomil, terazol, thiobendazole, arietti (all are trade names), copper sulfate Etc. can be used. Since the bactericide may inhibit germination, infection, and hyphal elongation of VA mycorrhizal fungi, it is preferably applied at a low concentration.

In rice paddy, mullet seedlings often occur,
This is a phenomenon caused by molds such as Rhizopus, Trichoderma and Fusarium. However, VA for paddy rice
When the mycorrhizal fungus infects, it competes with the causative fungus of the mullet fungus, so that the effect of suppressing the murre bacterium is also obtained.

The method of cultivating paddy rice to which VA mycorrhizal fungus is applied is as follows:
It may be performed by a known method. By applying VA mycorrhizal fungi to the paddy rice and cultivating the seedlings while taking care not to make the root environment of the paddy rice anaerobic as described above, the growth of the paddy rice is promoted and healthy seedlings are cultivated. be able to.

[0017]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Example 1 and Comparative Examples 1 to 3 Stump stumps were collected from the fields of upland rice (cultivar Norin 26), and further 600 kg of fine roots and soil around the roots were collected. 9 this soil
It was packed in 10 containers of 0 × 60 × 30 cm, and 2 g of chemical fertilizer (N: P: K = 10: 10: 10) was added to each liter of soil. After planting 24 corns per container in this soil, the containers were placed in a greenhouse and appropriately irrigated, and cultivated for 4 months.

Thereafter, the corn was extracted and the soil was sufficiently removed from the roots. Spores of VA mycorrhizal fungi were collected from this soil using the wet sieving method. Most of the spores were spores of the genus Glomus, but also spores of the genus Gigaspora and Scatellospora. Collect only spores of the genus Glomus, Akadama soil: Bray clay: Kanuma soil = 1: 1:
300 to 1 g of the base material mixed at a ratio of 1 (weight ratio)
After mixing at a ratio of individual pieces, they were stored in a refrigerator at 4 ° C for one month.

[0019] 1.7 liters of seedling cultivation soil for paddy rice (manufactured by Kureha Chemical Co., Ltd.) was put in a seedling box of 60 × 30 × 5 cm,
20 g of the base material containing VA mycorrhizal spores stored in a refrigerator was spread per seedling raising box. On top of this, 0.4 liters of the seedling-raising soil was covered, and the seedlings were placed in a greenhouse at 27 ° C. and left for 7 days with daily watering. After that, seed sterilized and seedlings of Koshihikari seed that had been subjected to sprouting treatment (for 2 days) were sowed, and 0.8 liter of seedling cultivation soil was sprinkled on the seed.

The seedling raising box was kept at a minimum temperature of 18 ° C. and was raised for 22 days in a vinyl greenhouse. Table 1 shows the height (plant height) of the above-ground part of rice and the infection rate of VA mycorrhizal fungi after raising seedlings (Example 1). In addition, the results of raising seedlings by the same method except that VA mycorrhizal fungus was not added are shown in Table 1 (Comparative Example 1). Further, a test was conducted in the same manner as in Example 1 except that the sun-dried soil of paddy field was used without using the above-mentioned seedling cultivation soil for paddy rice (Comparative Examples 2 and 3). Shown in.

[Method of Measuring Infection Rate] First, trypan blue was used for staining according to the following procedure. (A) Rinse the collected plant roots with water to remove the soil. (A) The drained root is placed in a beaker, soaked in a 10% KOH solution, and gently boiled for 1 hour. At this time, cover the upper part. In addition, boiling may be done with hot water. (C) Discard the KOH solution and bleach for 30 minutes with a 10 times diluted hydrogen peroxide (about 3%) solution. It may be omitted if the root pigment is low. (D) The roots are dipped in a lactophenol-trypan blue dyeing solution having the composition shown below and boiled gently for 5 to 30 minutes to dye. * Composition of lactophenol-trypan blue dyeing solution Carbolic acid (phenol) 200 ml Distilled water 200 ml Lactic acid 200 ml Glycerin 400 ml Trypan blue 1 g Total 1000 ml (e) Rinse the dyed root with water and wash away the dyeing solution. (F) Put roots in a dish filled with water and observe with a stereomicroscope. Next, the infection rate was calculated as follows. The sample was placed on a grid at 1 cm intervals, and the stained portion was counted from 100 spots on the grid by a stereoscopic microscope to obtain the infection rate.

[0022]

[Table 1]

[0023]

According to the method of the present invention, it is possible to infect paddy rice with VA mycorrhizal fungi. as a result,
The growth of paddy rice can be promoted and the occurrence of diseases can be suppressed. Since paddy rice is a basic agricultural crop of Japan, the utility of the present invention is extremely high.

Claims (2)

[Claims] 1. When cultivating paddy rice, VA is applied to the paddy rice.
A method for cultivating paddy rice, which comprises applying a mycorrhizal fungus and culturing under aerobic conditions. 2. The aerobic condition is a redox potential of −100.
The method according to claim 1, which is mV or higher.