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Agaricus bisporus is a popular edible mushroom that is cultivated worldwide. Due to its secondary homothallic nature, cultivated A. bisporus strains have low genetic diversity, and breeding novel strains is challenging. The aim of this study was to investigate the genetic diversity and population structure of globally collected A. bisporus strains using simple sequence repeat (SSR) markers. Agaricus bisporus strains were divided based on genetic distance-based groups and model-based subpopulations. The major allele frequency (MAF), number of genotypes (NG), number of alleles (NA), observed heterozygosity (HO), expected heterozygosity (HE), and polymorphic information content (PIC) were calculated, and genetic distance, population structure, genetic differentiation, and Hardy–Weinberg equilibrium (HWE) were assessed. Strains were divided into two groups by distance-based analysis and into three subpopulations by model-based analysis. Strains in subpopulations POP A and POP B were included in Group I, and strains in subpopulation POP C were included in Group II. Genetic differentiation between strains was 99%. Marker AB-gSSR-1057 in Group II and subpopulation POP C was confirmed to be in HWE. These results will enhance A. bisporus breeding programs and support the protection of genetic resources.

Agaricus bisporus, commonly known as the button mushroom, is widely cultivated throughout the world. To breed new strains with more desirable traits and improved adaptability, diverse germplasm, including wild accessions, is a valuable genetic resource. To better understand the genetic diversity available in A. bisporus and identify previously unknown diversity within accessions, a phylogenetic analysis of 360 Agaricus spp. accessions using single- nucleotide polymorphism genotyping was performed. Genetic relationships were compared using principal coordinate analysis (PCoA) among accessions with known origins and accessions with limited collection data. The accessions clustered into four groups based on the PCoA with regard to genetic relationships. A subset of 67 strains, which comprised a core collection where repetitive and uninformative accessions were not included, clustered into 7 groups following analysis. Two of the 170 accessions with limited collection data were identified as wild germplasm. The core collection allowed for the accurate analysis of A. bisporus genetic relationships, and accessions with an unknown pedigree were effectively grouped, allowing for origin identification, by PCoA analysis in this study.

We designed 170 new simple sequence repeat (SSR) markers based on the whole-genome sequence data of button mushroom (Agaricus bisporus), and selected 121 polymorphic markers. A total of 121 polymorphic markers, the average major allele frequency (MAF) and the average number of alleles (NA) were 0.50 and 5.47, respectively. The average number of genotypes (NG), observed heterozygosity (HO), expected heterozygosity (HE), and polymorphic information content (PIC) were 6.177, 0.227, 0.619, and 0.569, respectively. Pearson’s correlation coefficient showed that MAF was negatively correlated with NG (−0.683), NA (−0.600), HO (−0.584), and PIC (−0.941). NG, NA, HO, and PIC were positively correlated with other polymorphic parameters except for MAF. UPGMA clustering showed that 26 A. bisporus accessions were classified into 3 groups, and each accession was differentiated. The 121 SSR markers should facilitate the use of molecular markers in button mushroom breeding and genetic studies.

The white button mushroom (Agaricus bisporus) is one of the most widely cultivated species of edible mushroom. Despite its economic importance, relatively little is known about the genetic diversity of this species. Illumina paired-end sequencing produced 43,871,558 clean reads and 69,174 contigs were generated from five offspring. These contigs were subsequently assembled into 57,594 unigenes. The unigenes were annotated with reference genome in which 6,559 unigenes were associated with clusters, indicating orthologous genes. Gene ontology classification assigned many unigenes. Based on genome data of the five offspring, 44 polymorphic simple sequence repeat (SSR) markers were developed. The major allele frequency ranged from 0.42 to 0.92. The number of genotypes and the number of alleles ranged from 1 to 4, and from 2 to 4, respectively. The observed heterozygosity and the expected heterozygosity ranged from 0.00 to 1.00, and from 0.15 to 0.64, respectively. The polymorphic information content value ranged from 0.14 to 0.57. The genetic distances and UPGMA clustering discriminated offspring strains. The SSR markers developed in this study can be applied in polymorphism analyses of button mushroom and for cultivar discrimination.

The production scale of mushrooms in Korea is approximately 600 billion won, which is 1.6% of Korea’s gross agricultural output. In Korea, ca. 190,000 tons of mushrooms are harvested annually. Although the numbers of mushroom farms and cultivators are constantly decreasing, total mushroom yields are increasing owing to large- scale cultivation facilities and automation. The recent expansion of the well-being trend has caused an increase in mushroom consumption in Korea: the annual per capita mushroom was 3.9 kg (’13), whichis a little higher than that in Europe. Thus, mushroom export, mainly Flammulina velutipes and Pleurotus ostreatus, has increased since the mid-2000s. Recently, however, it is slightly reduced. Nevertheless, Vietnam, Hong Kong, the United States, and the Netherlands continue to export mushrooms, and Korea has increased its export to Australia, Canada, Southeast Asia, etc. Canned Agaricus bisporus, the first export of the Korean mushroom industry, reached it speak sales in 1977-1978. When Korea initiated trade with China in 1980, the international prices of mushrooms fell sharply, leading to shrinkage of the domestic markets. Spurred by the high demand to develop substitute goods for A. bisporus, the oyster mushroom (P. ostreatus) gained attention since it seemed to suit the taste of Korean consumers. Although the log cultivation technique for oyster mushroom was developed in the early 1970s, it required a great deal of labor. Thus, we developed the shelf cultivation technique, which is easier to manage and allows for mass production. In this technique, the growing shelf is made mafrom fermented rice straw, whichis the only P. ostreatus medium in the world and isused only in South Korea. After then, the use of cotton wastes as an additional material of medium, the productivity. Currently, we are developing a standard cultivation technique and environmental control system that can stably produce mushrooms throughout the year. The increase of oyster mushroom production may boostthe domestic market and contribute to industrial development. In addition, oyster mushroom production technology played a role in forming the basis for the development of bottle cultivation, which made mass production . In particular, bottle cultivation using liquid spawn could allow for the export of F. velutipes and Pleurotus eryngii. In addition, the white varieties of F. velutipes were second developed in the world after Japan. We also developed the new A. bisporus cultivar ‘Saeah’, which is easy to grow in Korea. In hopes to advance the mushroom industry, we will continue to develop cultivars with international competitive power and to improve cultivation techniques.

Breeding the button mushroom requires genetic information about its strains. This study was undertaken to genetically characterize four domestically bred button mushroom strains (Saea, Saejung, Saedo, Saeyeon cultivars) and to assess the possibility of using the intergenic spacer 1 (IGS1) region of rDNA as a genetically variable region in the genetic characterization. For the experiment, 34 strains of Agaricus bisporus, two strains of A. bitorquis, and one strain of A. silvaticus, from 17 countries were used. Nucleotide sequence analysis of IGS1 rDNA in these 37 Agaricus strains confirmed that genetic variations exist, not only among the four domestic strains, but also between the four domestic strains and foreign strains. Crossing two different haploid strains of A. bisporus seems to generate genetic variation in the IGS1 region in their off-spring haploid strains. Phylogenetic analysis based on the IGS1 sequence revealed all A. bisporus strains could be differentiated from A. silvaticus and A. bitorquis strains. Five genetic groups were resolved among A. bisporus strains. Saejung and Saeyeon cultivars formed a separate genetic group. Our results suggest that IGS1 could be complementarily applied in the polymorphism analysis of button mushroom.

White button mushroom (Agaricus bisporus) is the most widely consumed mushroom in the world, and domestic consumption is increasing owing to expansion of the westernized diet in recent years. Before 2000, most Korean mushroom farmers cultivated foreign varieties, but recently, Korean breeders are developing hybrid strains using molecular breeding tools. To produce a better mushroom cultivar, we evaluated some traits of button mushroom Agaricus bisporus strains. Mycelial growth rate at different culture temperatures was investigated by 25>20>15>30>10oC. Recently developed domestic varieties had superior mycelial growth rate compared to the traditionally grown species. In particular, the ASI1338 strain showed excellent mycelial growth rate at different temperatures. Further, we confirmed that ASI1007, ASI1085, ASI1310, ASI1339 were strongly resistant to bacterial brown blotch, whereas ASI1053, ASI1103, ASI1140, ASI1146, ASI1177, ASI1183, ASI1195, ASI1321, ASI1331, ASI1336 were relatively weakly resistant. The average number of days for 16.5, and that for harvest was 5.7; the average yield was 142.7 g/2-kg bag. Mycelial growth rates at 10, 15, 20, 25oC were similar, but that at 30? was lower. The mushroom yield was highly correlated with the number of days for pinheading and harvest.

Agaricus bitorquis is an edible white mushroom of the genus that is cultivated at high temperature(25±1 o C) unlikeA. bisporus is cultivate at 16±2 o C. Unlike Agaricus bisporus, an edible white A. bitorquis mushroom is cultivated at hightemperature (25±1 o C). Most farmers cultivate this mushroom for a long cultivation period in Korea. For this reason, we madeheterokayons to develop a new cultivar that generate fruitbodies for short cultivation period. Over one hundred SSIs(singlespores isolates) were collected from selected A. bitorquis ASI1151 and ASI1349 strains. Seventy-three SSIs were germinated onCDA(compost dextrose agar) media after 20 days (minimum) or 83 days (maximum) incubation under different mediacondition. The mycelial growth rate of germinated SSIs was different. 9 homokaryons in ASI 1151 and 11 homokaryons in ASI1349 from SSIs were selected by OPN-02 primer in RAPD analaysis. Also this primer was used to select heterokaryon thatcross among each homokaryon with compatible locus. Therefore 44 compatible matings were confirmed of 99 crossed lines. KEYWORDS: Agaricus bisporus, Brown cultivar, Morphological and cultivational characteristics

A new brown button mushroom cultivar, ‘Hogam’, C34 line, was made by crossing homokaryons, ASI1164-37 andASI1175-66, selected by RAPD analysis and by cultivating three times. Mycelium of ‘Hogam’ on CDA (compost dextrose agar)media grew well at 25 o C. The optimum pin-heading temperature of new variety and optimum growing temperature was 14-18 o C. The thickness of the mature cap and stipe were thicker than a control, ‘Dahyang’ that developed in 2010. The color ofpileus was light brown and lighter than ‘Dahyang’. Days required from casing to first harvesting were three days longer thancontrol strain, but the weight of harvested fruiting body increased by 1.35 times. ‘Hogam‘ cultivar are expected to contribute tothe diversification of domestic mushroom cultivars.KEYWORDS: Agaricus bisporus, Brown button mushroom cultivar, Morphological and cultural characteristics 서론 양송이(Agaricus bisporus)는 생긴 모양을 빗대어 buttonmushroom으로 불리며, 식용버섯으로 맛과 향기가 뛰어나서 세계적으로 가장 널리 소비되는 버섯 중 하나이다(Jzsefet al. 2004). 최근 우리나라의 양송이 생산량은 6,678MT이고, 생산액은 433억이다(Special crop production in 2013).양송이에는 일반적으로 많이 소비되는 백색양송이 와 갓이갈색을 띄는 갈색양송이로 구성된다. 특히 갈색양송이는크래미버섯, 베이비 포토벨로, 베이비벨라, 미니벨라, 포터벨리니, 로먼버섯, 이탈리아버섯 또는 갈색버섯등과 같은여러 이름으로 불리며 일반 버섯보다 크게 키워, 갓이 약간벌어진 형태의 버섯은 potobello라고 불린다. 우리나라에서는 갈색양송이는 병충해에 강해 과거 705 등을 재배하였으나 가격이 낮고 재배규모는 적어 학교급식을 납품하는 농가에서 소규모로 재배를 하고 있다.양송이는 다른 버섯과 달리 이차 자웅동주성(secondaryhomothalism)으로 한 담포자내에 두 개의 반수체핵(haploidnuclei) 을가지는다핵성(multinucleate) 지닌다. 이에따라 교잡을 하지 않아도 포자내에 화합성을 가진 두 개의 핵이 임성을 띄어 대다수의 담자포자가 자실체를 형성한다.이에교잡을위한동핵균주확보가어렵고, 교잡후꺽쇠연결체(clamp connection)가 형성되지 않아 교잡을 확인하기가 어렵다(Rapar and Raper, 1972). 현재까지 육종연구는돌연변이(Fritsche, 1965; Stoller and Stauffer, 1953), 교배(Elliott, 1978; Kneebone, 1972; Moessner, 1962), 원형질체분리(Horgen, 1991), 형질전환(Rhee et al, 1996; Chen etal, 2000; Tomas et al, 2001) 등이 이루어졌다. 동핵균주의

Mushroom Research Division, Department of Herbal Crop Research, National Institute of Horticultural and Medicinal Crop RDA,Eumseong 369-874, KoreaABSTRACT: Button mushroom (Agaricus bisporus) strains from diverse origins were compared in this study to obtain basicinformation on their growth and biochemical properties that are helpful for breeding. Among 31 dikaryotic strains tested, moststrains showed better mycelial growth on oatmeal agar than on MEA and PDA. Mycelia of the mushroom strains revealed β-glucosidase activity the most clearly among the seven extracellular enzymes tested. All the strains showed protease activity, but β-glucosidase activity was found in 27 strains and xylanase activity was found in 30 strains. The activity of avicelase, CM-cellulase,amylase, and pectinase was detected in less than 20 strains. These results implied that enzymatic characteristics could be used asa criterion of strain selection for breeding study.KEYWORDS

This study was carried out to investigate storage stability of harvested mushroom in developed varieties of button mushroom through identification of quality change during 35 days. The mushroom harvested up to flush mushroom was stored on different storage temperature(4, 7, ) and weight, length, thickness, color of pileus and stipe in fruit body was tested every 7 days. The morphological trait and color of stipe in fruit body were influenced by harvesting period and storage temperature. On the morphological traits of fruit body, mushroom harvested at flush showed smaller difference than those at flush and mushroom stored at indicated more difference than ones at the other temperature. Mostly color of pileus in brown button mushroom had lower (color difference) than white mushroom during storage period. The color of pileus of fruit body in white mushroom had low at whereas that of brown mushroom was low at . The safe period of storage based on the L value is 7 days under a specified environmental condition. `Seolgang` was stored for 14 days as good quality of mushroom, `Saedo` had best quality after harvesting and `Seojeong` was most stable during storage change in white mushroom varieties.