Patent Application
20230148465
This invention relates to a new and distinct variety of Bunashimeji mushroom, Hypsizygus marmoreus (Peck) H.E.Bigelow. This new variety named ‘HKHM25,’ cultivated by repeated breeding of Bunashimeji mushroom having thick and elastic stems, dark cap color, strong cap roll, and a large mushroom size, has a high quality and enhanced cultivation stability, and ensures presentable stability, reproducibility, and uniformity.
The annual production of Bunashimeji mushrooms is approximately 120,000 tons in 2020, making it the second most consumed edible mushroom after enokitake mushroom in Japan. However, since Bunashimeji mushrooms have become available in large quantities in the market, Bunashimeji mushrooms with improved flavor, quality and shelf life has been pursued, which led to the development of ‘Hokuto 18gokin’ by our company. Further, our company has been conducting a wide variety of studies for the more stable cultivation and better quality of Bunashimeji mushrooms. Our company has developed a ‘marmo22go’ mushroom which is thicker, whiter, and has larger mushroom than ‘Hokuto 18gokin’.
Further, using ‘marmo22go’ as a parent, as a result of continuing breed improvement by cross breeding to improve stability and quality, ‘HKHM25’, which has thicker stems and stronger cap roll, as compared to ‘marmo22go’, was developed, confirming its stability, reproducibility, and uniformity.
The present invention is a new and distinct variety of mushroom plant characterized particularly by having thick and elastic stems, dark cap color, strong cap roll, and a large mushroom size, which can be cultivated by gathering and repeated breeding of fungal strains having a stability, reproducibility and uniformity when being produced. This novel and distinct variety of mushroom is identified as ‘HKHM25’.
‘HKHM25’ has been asexually reproduced by tissue culture, at HOKUTO CORPORATION in Japan. The history of the ‘HKHM25’ mushroom in terms of improvement period and the like are set forth in the following chronological list of each stage of variety improvement:
December 2014: Cultivation of ‘MH025615’ strain.
January 2017: Cultivation of ‘MH025617’ (‘marmo22go’) strain.
December 2019: ‘MH025615’ and ‘MH025617’ (‘marmo22go’) strains were crossed and a strain with thick stem, strong cap roll, and good quality among the obtained strains was selected as ‘MH025633’. We then repeated the cultivation test to distinguish the strains.
March 2021: After repeated cultivation tests, since distinguishability, stability, and uniformity were confirmed, the strain was named ‘HKHM25’ and its cultivation was completed. Applied for registration of a new variety to the Ministry of Agriculture, Forestry and Fisheries of Japan.
The above crossing is summarized in the phylogenetic tree illustrated in
The ‘HKHM25’ mushroom has the following characteristics: thick and elastic stems, dark cap color, strong cap roll, and overall large size.
(1) Comparison with Existing Variety by Dual Culture
Dual culture was performed for the ‘HKHM25’ mushroom and a similar variety to examine whether or not a zone line is formed.
As an examination method, a potato dextrose agar medium was used, and the ‘HKHM25’ mushroom and the similar variety were inoculated thereon face to face at an interval of 3 cm, and then culture was performed at 25° C. for 28 days to examine whether or not a zone line was formed.
Strains used for the comparison between present variety, ‘HKHM25’ and other varieties:
Zone lines were formed between ‘HKHM25’ and all other co-cultured varieties (Table 1,
After inoculating an agar piece of the ‘HKHM25’ having a diameter of 5 mm and an agar piece of the similar variety having a diameter of 5 mm on a potato dextrose agar medium, preculture was performed at 25° C. for 4 days so as to make the regeneration of hyphae equal (about 10 mm in diameter), and then culture was performed for 7 days at intervals of 5° C. between 5° C. and 30° C. An average daily hyphae growth rate was calculated based on a hyphae growth rate for 7 days of the culture. Also, the optimum culture period for ‘HKHM25’ is 80 days, and the number of growing days at that time is 23.1 days.
‘HKHM25’ had the fastest average daily hyphae growth rate at 20° C. In addition, HKHM25 had slower mycelial growth rate than ‘Hokuto 18gokin’ and ‘marmo22go’ at each temperature zone (Table 2).
Container: An 850 polypropylene bottle (Capacity: 850 ml, diameter 58 mm) was used.
Culture medium: Conifer sawdust, corn cob, rice bran and wheat bran were mixed at the dry weight ratio of 7:3:8:2, and the water content was adjusted to 65%. The culture medium was filled up to the brim of the bottle at the rate of 540±20 g per bottle, and was sterilized at high pressure.
Starter culture: About 20 ml of sawdust starter cultures per bottle was inoculated.
Culture: Culture was performed at 22° C. for 50 to 90 days at 70% moisture.
Growth: After completing the culture, the inoculum is removed, and shifted to a growing room. Development was conducted under a temperature of 15±1° C., at humidity of 95% or about 2,000 ppm CO2 density. Also, light was not particularly irradiated until the first 14th day, then irradiated with about 500 to 1,000 Lx. The mushroom is harvested when the cap in the center of the stump has sufficiently opened.
Table 2 shows the characteristics of the ‘HKHM25’ and specific difference in characteristics as compared with the similar variety when culture was performed under the abovementioned conditions.
In addition, according to R.H.S. Colour Chart, the color of the central part of cap: 199A, the color of the peripheral area of cap: 199C, the color of gill: 158C, the color of stripe: 155B. All color references are from The R.H.S. Colour Chart of The Royal Horticultural Society of London (R.H.S.), fifth edition published in 2007. Also, the descriptions are from mushrooms that are on the 24th day.
/mm
| Number | Date | Country | Kind |
|---|---|---|---|
| 35308 | Mar 2021 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| 20220304209 P1 | Sep 2022 | US |
