Introduction to heirloom vegetables in Kyoto prefecture ( Kyo - yasai ), Japan

The group of vegetables known collectively as Kyo-yasai is a key part of food culture in Kyoto, once Japan’s capital city for over 1000 years. A favorable climate and other cultural influences enabled Kyo-yasai culture to flourish. This study reviews the history, work to preserve, and marketing of Kyo-yasai . It also summarizes the scientific research conducted in the past few decades concerning breeding, functionality, nutrition, and taxonomy to provide an overview of Kyo-yasai today. The first record of heirloom vegetables in Japan was in the third century. After Kyoto became the capital in 794, a variety of vegetables were gradually introduced, and these have been developed and selected as Kyo-yasai for many centuries now. However, F 1 vegetable cultivars became the national norm after World War II, and Kyo-yasai faced the risk of extinction. Consequently, farmers, researchers, municipalities, and other groups decided to preserve Kyo-yasai. In 1974, the Kyoto prefectural government began preserving Kyo-yasai seeds. At the time it also defined 37 heirloom vegetables as ‘traditional Kyo-yasai .’ Additionally, agricultural cooperatives, wholesale markets, restau‑ rants, and municipalities started to promote sales of Kyo-yasai . Furthermore, a breeding program was set up by Kyoto prefectural institutes looking at ways of improving cultivation suitability. Functional and taxonomical research by Kyoto Prefectural University and other organizations has revealed not only that Kyo-yasai has higher functionality overall compared than common F 1 cultivars, but also the genomic uniqueness of Kyo-yasai . These efforts collectively improved our understanding of Kyo-yasai and promoted their production. The preservation of these heirloom vegeta‑ bles has a clear benefit in that it would contribute to the diversity of species and food cultures.


Introduction
Since ancient times, Japanese farmers have cultivated a wide variety of vegetables, owing to its warm and humid climate, and also because of cultural influences from neighboring countries.While serving as the capital for over a thousand years, the cultural and population center of Kyoto helped the cultivation of vegetables to flourish in areas surrounding the city.The cultural significance of vegetables in Kyoto, along with the abundance of varieties, has been documented and passed down to the present day.However, seed companies have introduced new cultivars, particularly of the hybrid (F 1 ) type, and these have become increasingly competitive in the market in the past sixty years [1].Therefore, it is necessary to improve the cultivation suitability, quality, and yield of heirloom vegetables in Kyoto (Kyo-yasai) for growers and markets in the region.
The word 'Kyo-yasai' is generally used to denote vegetables produced in Kyoto in a broad sense, although there is no clear definition.In this paper, it means the vegetables grown using heirloom seeds in Kyoto.
This paper aims to provide an overview of the history, efforts at preservation, and sales promotion of Kyoyasai.Additionally, it summarizes the scientific research conducted in the past few decades regarding breeding, functionality, nutrition, and taxonomy to provide a current understanding of Kyo-yasai.
The relationship between the description of old literature and the current classification may be unclear.Therefore, ancient references are summarized in Table 1, and literature after 1602 is listed in the 'References' section.

Brief history of vegetables in Japan
The Japanese archipelago is a long stretch of islands from south to north, covering northern latitudes of 24° and 46°.As a result, climatic conditions vary from semi-tropical to cold, depending on the region.Consequently, various heirloom vegetables are available in each district of Japan.Vegetables such as Asatsuki, Chinese chive, Goldband lily, Japanese butterbur, Japanese hornwort, Japanese pepper, mioga ginger, rakkyo, Udo ginseng, wasabi, water dropwort, and water shield have been grown and domesticated through selection for over 2000 years.Brassicaceae leaf vegetables, including Komatsuna and Mizuna, Japanese radish (daikon), pickling melon, taro, and Welsh onion, were introduced from China, Korea, and Southeast Asia before the seventh century [2].Cowpeas, cucumbers, eggplants, lettuce, and turnips were introduced up until the ninth century.Many of these species have several variations depending on their growth areas.Heirloom daikons and turnips have diverse shapes and colors, while Mizuna and Komatsuna have many useful varieties of leafy vegetables.Welsh onion also has many variations and cultural methods [3].
After the arrival of the Portuguese in Japan in 1543, many vegetables originating from North and South America were introduced in the late sixteenth and early seventeenth centuries, such as chili pepper, corn, potato, and squash.
During the Edo era (1603-1868), Japanese society experienced over 250 years of peace and the country effectively cut itself off from the rest of the world.During this time horticulture became popular in all sections of society.
Starting in the Meiji era (1868), the Japanese government introduced various crops from European countries, the USA, and China, and attempted to produce them throughout Japan.Tomatoes, cabbages, and other vegetables were adopted, and agricultural public research stations established in every prefecture conducted cultivation experiments and bred cultivars suitable for the Japanese climate.Notably, Japanese plant breeders pioneered the development of F 1 hybrid vegetables in the early twentieth century.Although F 1 hybrid cultivars currently dominate in Japan, some heirloom vegetables have been conserved.Local organizations and groups continue to promote the production and distribution of these varieties.[4].

Brief introduction of Japanese culture related to vegetables and the role of Kyoto
By the end of the fourth century, the Kinki region, including Kyoto prefecture, became the center of the most powerful administration in Japan.Heian-Kyo was founded as the ancient capital of Japan in 794 where Kyoto City is located today.It remained the imperial capital of Japan until 1869, although Ieyasu Tokugawa established an administrative center in Edo (now Tokyo) in 1603 (Fig. 1).
During the Heian era (794-1191), it is estimated that Kyoto's population was between 150,000 and 200,000 [5].As a result, many novel varieties of vegetable seeds were collected and cultivated around the capital to supply large quantities of fresh vegetables to the residents.
Soil and climatic conditions have played a key role in the development of Kyo-yasai [6].However, aspects of culture, politics, and religion also helped to make these vegetables more popular.In Kyoto, a palace-style cuisine called Yusoku-ryori was enjoyed by the Imperial Court, court nobles, and top-ranking members of the shogunate in the old days.Nowadays, a few restaurants still serve these dishes.Furthermore, since most Buddhists were Fig. 1 Location of Kyoto prefecture, and major names of places in the prefecture.Source Created and edited by the author from free illustrations vegetarians, so Shojin-ryori, a special vegetarian cuisine, was developed.Lastly, tea ceremonies have been popular in Kyoto since the sixteenth century [7], and Kaisekiryori dishes were served during these events.Vegetables are one of the main ingredients in these dishes [7,8].
After the Meiji Restoration, the emperor moved to Tokyo, and Kyoto City ceased to be the capital of Japan.The population declined for a period, but various industrial promotion projects were implemented, resulting in an increase until 1970.This also meant that the amount of farmland decreased.The production areas of heirloom vegetables shifted, and farmers stopped cultivating some varieties.However, the urbanization of Kyoto was relatively slow compared to other major cities such as Tokyo, Osaka, and Nagoya, and many varieties of Kyo-yasai have been preserved than the ones in other cities.This was largely due to persistent consumer demand for each variety of Kyo-yasai [9][10][11][12].

Natural conditions and climates of Kyoto
Kyoto prefecture is composed of Kyoto City and three regions named Yamashiro, Tamba, and Tango (Fig. 1).The prefecture is long and narrow, stretching from north to south, with the northern area facing the Sea of Japan, and the rest consisting of hilly and mountainous areas.Most cities, including Kyoto, are situated in basins, and most vegetable farms are located around the cities and valleys.
The winter in Kyoto prefecture is mild, and even if it snows in the Tango region that faces the Sea of Japan, it does not snow heavily in the southern regions, such as Kyoto City and Yamashiro.In summer, there is a lot of rain, and the air temperature and relative humidity are high.Therefore, varieties of vegetables with tropical origins grow well in the summer.

Indigenous species
Out of all the indigenous vegetables in Japan, Japanese butterbur, Mioga ginger, Udo ginseng, water dropwort, and water shield are the most important Kyo-yasai species (Fig. 2).The history and characteristics of these five species are summarized in Table 2.

Non-native species
Leaf vegetables Brassicaceae leafy vegetables have also been popular in Japan.Mizuna has a pinnatisect leaf type and originally had enlarged turnip-like roots, although, at present, Mizuna has been developed to decrease the size of the root.Another leaf vegetable in Kyoto, Mibuna, which has simple spatulate leaves, was obtained by selecting Mizuna in the mid-nineteenth century (Fig. 3) [16].Research results of genome studies of Mizuna, Mibuna, and turnips have indicated that Mibuna may have been established by crossing a simple-leaf turnip with Mizuna [17].Recent genetic analysis has revealed that the typical modern Mizuna cultivar, Jonan-sensuji, is closely related to the local turnip variety Omi-kabura among several local varieties of leaf and root vegetables [18].
Welsh onion also has many variations spread across three types named Kujyo, Kaga, and Senju in Japan [19].The Kujo type is mainly cultivated in Kyoto prefecture.It is said that Welsh onion spread to Japan in prehistoric times.Therefore, according to Kyotofu-Engeiyoukan [20], there is an oral monument that says they started cultivating Welsh onion when the Inari Shrine was built in 711 (Fig. 1,4).

Root vegetables
Arrowhead is a perennial that grows or is cultivated in the temperate and tropical zones of the Northern Hemisphere.It is used as a vegetable across Asia and has a bitter taste [21].
Burdock has been acknowledged as a medicinal plant in East Asia [22].It is also abundant in Japan and has long been domesticated as a vegetable.Burdock root is crisp and has a sweet, mild, or pungent flavor with little muddy harshness.Burdock has only recently become popular outside Japan [6].
Carrot domestication occurred before the tenth century in Afghanistan [23].Cultivated carrots can be divided into eastern and western carrot types.The eastern carrots originated in Central Asia [24], and these two types have genetically distinct differences [25].Eastern carrots were introduced to Japan through China up until the seventeenth century [26].In those days, the carrots were red, purple, yellow, and white [27].The red variety is still cultivated in Japan and some other Asian countries, although western orange carrots have prevailed in Japan in the last half-century.This red carrot, named Kintoki, is popular in Western Japan (Fig. 5).Osaka was a production area in 1855 [28].It was also produced in Higashi-Kujo and Kamitoba in Kyoto City during the Meiji era (1868-1912) [12].The total carrot production was 1017 t and 67 ha in Higashi-Kujo in 1935 [29] (Fig. 1).Japanese radish, belonging to the Daikon group, came to Japan in the prehistoric era and became one of the major vegetables in the production and planting areas in Japan.Depending on the variety, they differ in size, shape, color, and taste.Some even have curved roots.Kyoto prefecture has seven Kyo-yasai varieties of Daikon.Kyoto City has the round-rooted Shogoin-daikon, the long, normal-sized Kuki-daikon, Momoyama-daikon, and Tokinashi-daikon.Sabaga-daikon comes from Maizuru City (Fig. 1), which faces the Sea of Japan, and is known as a remarkably late variety.It was domesticated from a wild plant called Hama-daikon that grows along the coast [30].Karami-daikon is a small variety used as a condiment because of its pungent taste.Aomi-daikon is a smaller variety characterized by the greenish color of the top of the root and the lack of straight root growth (Fig. 6).
It is said that a local Taro variety in Nagasaki was introduced to Kyoto in the Edo era.The variety was well-cultivated in rich soil and capable of producing large and curved taro (300 g).Because the shape resembled lobster, the variety was called Ebi-imo (Ebi means lobster in Japanese) (Fig. 7).
Turnip accessions and local varieties in Japan have been divided into three groups according to seed type [31] and geographical distribution [32,33].However, recent molecular studies have revealed that the three groups do not constitute genetic diversity, because most Japanese accessions and local varieties originate from central Asia [34].At present, it is believed that various economic traits of turnip in Japan are created by local demand and selection.The genetic relationships between Kyo-yasai and the surrounding areas have been investigated in detail [35].Some of the results contradicted the old records that say the Omi turnip was the ancestor of the Shogoin turnip [18].Among the various turnip varieties in Kyoto, the Suguki turnip is a distinctive group used for Japanese salty lactic fermented pickles.After the Edo era, approximately 150 years ago, the production of Suguki pickles increased.The fast-increasing production led to a general deterioration in the quality of the lines, and a mixture of good and bad seeds were sold.Therefore, an attempt to uncover the standard Suguki appearance in 1973 contributed to subsequent breeding efforts [36] (Fig. 8).
In addition, six other Kyo-yasai varieties are available, including Matsugasakiukina-kabu and Uguisuna, whose leaves are also actively used.Maizuru-kabu is characterized by its purple upper root surface (Fig. 9).
Sprout vegetables Several types of bamboo shoots have been used as vegetables in Asia.In Japan, Moso bamboo (Moso-chiku in Japanese) was popular until the end of the seventeenth century in Kyoto because of its higher yield and better quality than other types of bamboo.Growers in Kyoto have practiced special techniques and improved the ground's physical properties by spreading straw in the bamboo groves and add 3 to 5 cm of soil on top of it every year.This makes it easier for underground stems to grow and increases the softer part of the bamboo shoots because of the deeper position of the underground stems.Bamboo shoots are harvested after they appear on the surface of the ground, resulting in a darker peel.However, in Kyoto, the soft soil is dug up when the surface swells or cracks before the shoots emerge at the surface, resulting in the entire harvest being softened, and the peel being light yellow.For this reason, the former is called Kuroko (black one) and the latter Shiroko (white one) in Kyoto, and the latter is sold at a higher price [37].
Hanana is a Brassicaceae vegetable whose flower buds are harvested in early spring and is characterized by its bitter taste.
Fruit vegetables Cucumber was introduced to Japan a long time ago.However, until the late Edo era, it was not popular in Kyoto.It has a bitter taste and a spine on the fruit peel.Another cucurbitaceous plant, the oriental pickling melon was popular in Kyoto at that time [38].Nevertheless, cucumber was used in forcing culture in Shogoin village in Kyoto in the late Edo era (Fig. 1).
Eggplants are popular in South and East Asia.The colors of eggplants were purple, white, and green.In Japan, they have spread to most regions and been differentiated into various local varieties, even during the Edo era.During that time, there were two major shape types of eggplants: one with elongated fruit and the other round.Yamashina-nasu and Kamo-nasu in Kyoto are examples of the former and latter type, respectively.There is also a variety called Mogi-nasu which can be harvested early, with each fruit weighing about 20 g (Fig. 10).
Pickling melon was cultivated in Soraku-gun, southern Kyoto prefecture, approximately 1000 years ago.It was cultivated in Katsura village in Kyoto in the late Edo era, and the production area extended to neighboring villages before World War II.
Several pepper varieties were introduced to Japan in the sixteenth century.It became popular in the early seventeenth century as a condiment.Most varieties exhibit pungency, however, an almost non-pungent variety called Fushimi-ama emerged in the Fushimi ward of Kyoto [39] (Fig. 1).It is used as a vegetable.Manganji is another sweet pepper variety which was cultivated in Maizuru City, Kyoto prefecture around 100 years ago.It was sold exclusively in Maizuru City until 1982 [40], after which it grew in popularity across the country.
Pumpkin was introduced to Japan in a manner similar to pepper.There are three major pumpkin species, Cucurbita maxima, C. moschata, and C. pepo.The old Japanese pumpkin varieties were all Cucurbita moschata species.In Kyoto, a gourd-shaped pumpkin variety Shishigatani was drawn in a picture named 'Kaso-Nehanzu' by a famous painter Jakuchu Ito in the eighteenth century [41] (Fig. 11).
Vegetable beans Cowpea, or Sasage, originated in Africa [42], but has spread and is widely cultivated as a legume variety across the world.Previously this was a well-established cereal crop, used over many centuries.However, a local variety Hiiragino-sasage has soft pods in its imma- Edamame is a preparation of immature soybeans in the pod, found in cuisines with origins in East Asia.The pods are boiled or steamed and may be served with salt or other condiments.The earliest documented reference to the term edamame dates from the year 1275 when the Japanese monk Nichiren mentioned it [43].

The rise of hybrid vegetable cultivars and the decline of heirloom vegetables after World War II, followed by efforts to revive Kyo-yasai in recent decades
According to a survey conducted by the Ministry of Agriculture, Forestry, and Fisheries (MAFF) between 1970 and 1980, 1214 local vegetable varieties were identified in 65 crops throughout Japan, and Kyoto prefecture had the largest number of local varieties out of all the prefectures in Japan [44,45].However, in 1948, Takii seed (Kyoto) sold its first domestic F 1 tomato seeds.Since then, the development of crossbred F 1 cultivars of vegetables has progressed, and F 1 vegetable cultivars have become prevalent in the seed market thanks to several advantages, such as high productivity, suitability for distribution, and vigorous, uniform, and stable traits [1].
In contrast, both the quantity and variety of heirloom vegetables decreased during the same period [2].The work of people who prioritize food quality, genetic diversity, and tradition, as well as the support of public organizations led to a concerted effort to preserve heirloom vegetables.
Dr. Shiro Takashima of Kyoto Prefectural University conducted research on vegetables before and after World War II.With the cooperation of municipalities, agricultural organizations, and growers in Kyoto, he devoted himself to the preservation of seeds, while referring to the literature, and conducting research on their history and morphology.

Kyo-yasai
The Kyoto City municipal office also started a project in 1962 to promote the preservation of 10 varieties of vegetables by setting up a Special Vegetable Preservation Field (Kyoto-shi-Tokusan-Sosai-Hozonho).
The Department of Agriculture in the Kyoto prefectural government compiled a list of heirloom vegetables and fruits in the prefecture that should be preserved in 1960.The list includes 50 vegetable varieties from 15 vegetable species (Table 3; Fig. 12).
In 1974, the Department of Agriculture started the "Project for the Establishment of Traditional Vegetable Seedling Hoards (Dentoyasai-Gensyuho-Secchijigyo)" and the Prefectural Institute of Agriculture (merged and renamed as Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center (KAFF) in 2009) interviewed production farmers about their cultivation methods, received seed and seedling donations along with their records, and preserved their original seeds [46][47][48], work which still continues in the present day [49].
As the Kyoto prefectural government promoted the production of Kyo-yasai, it became necessary to differentiate Kyo-yasai varieties from other vegetable cultivars.Therefore, in 1987, the Department of Agriculture defined and organized the 'traditional Kyo-yasai' under the guidance of Dr. Takashima.
The definition of 'traditional Kyo-yasai' is the vegetables in Kyoto prefecture with a pre-Meiji history.The category of vegetables includes bamboo shoots but not wild vegetables, mushrooms, or ferns, and is limited to those with differentiated varieties or unique cultivation methods.Based on this definition, 37 types of vegetables were selected as traditional Kyo-yasai [44,50].Three types that are newer to cultivation but essential for market distribution were added as equivalent to Kyo-yasai, for a total of 40 types of vegetables selected as traditional Kyo-yasai (Table 4) [51].
Some of the traditional Kyo-yasai were also used for sales promotion by a semi-governmental institution named 'the Kyo-Branded Products Association, ' which was established in 1989, a move that once again drew the attention of the public [50].In response, scientific research on the cultivation, culture, functionality, and history of Kyo-yasai has flourished.Additionally, the Kyoto Prefectural Institute of Agriculture has been conducting breeding programs aimed at improving the cultivation suitability, productivity, and quality of Kyo-yasai while maintaining their characteristics.

Modern Kyo-yasai promotion policy
The Kyo-Branded Products Association designated Kyoto brand products to promote sales of Kyo-yasai.Currently, there are 20 vegetable items designated as Kyoto brand products, 15 of which are traditional Kyo-yasai (Table 4) [44].Since its establishment, Mizuna has been the leading product in sales promotions.The use of Mizuna in small bunches, the establishment of cultivation techniques, and the expansion of sales channels have increased the recognition of Kyo-yasai [52].However, after expanding its sales channels nationwide, Mizuna has become recognized as a common vegetable, and Ibaraki Prefecture (Fig. 1), which is adjacent to Tokyo, now accounts for half the domestic production of Mizuna.In addition, the expansion of sales channels for Kujo-negi has stimulated the consumption of leaf onions in eastern Japan, which is also becoming a common vegetable, and this has the paradox that the mass sales of one commodity make the item less attractive as a 'local' product [53,54].Moreover, the popularity of Mizuna and Kujo-negi also expanded the seed market.It resulted in private seed companies quickly developing new F 1 and mix-breed cultivars that did not resemble Kyo-yasai.So, these gradations of new cultivars prompted the need to define the traits of Mizuna and Kujo-negi in detail.Contrary to private seed companies, the KAFF has been promoting the improvement of varieties in pursuit of better productivity and quality, while conserving the characteristics of Kyo-yasai.Additionally, Kyo-yasai often has superior functional components to common vegetable cultivars [55][56][57], and efforts are being made to utilize these components [58].

Breeding program and technology development-Edamame, Pepper, and Taro (Ebi-imo)
The production of some Kyo-yasai has increased thanks to promotional work.However, there is strong competition between modern cultivars of the same species.Therefore, KAFF has been improving some crops, such as edamame (Fig. 13), pepper, and Ebi-imo.With edamame, some traits have been intensively improved, such as expanding the harvesting season, and developing resistance to soybean mosaic virus (SMV).
In 1975, cultivar Shin-Tambaguro seeds were irradiated with 10KR γ-rays, and mutant individuals were fixed and selected.One of the lines was registered in March 1993 as the edamame cultivar Murasaki-Zukin because of excellent traits, similar to those of edamame, and potential for early harvesting [59].Murasaki-Zukin can be harvested in late September or early October, whereas Shin-Tambaguro can be harvested in mid-to-late October.The number of main stem nodes was more than three less than that of Shin-Tambaguro, and the main stem length was approximately 15 cm shorter.
To make Murasaki-Zukin early-maturing and SMVresistant, KAFF developed a post-hybrid generation, then proceeded with fixation and selection using accelerated generation techniques.It applied for the cultivar registration of 'Murasaki-Zukin 2gou' in April 2006 [60].This cultivar can be harvested in early to mid-September and has a slightly shorter and more compact main stem.
To develop a variety that can be shipped in the summer season when the demand for edamame is high, Murasaki-Zukin was irradiated with γ-rays (dose 100 Gy), and the mutant plants were fixed and selected.This cultivar was registered as 'Natsudori-Tambakuro 2gou' in April 2010 [61] and was harvested in August.
To provide SMV resistance to Murasaki-Zukin, it was crossed with Murasaki-Zukin 2gou.Subsequently, KAFF backcrossed Murasaki-Zukin to the BC 2 generation for fixation and selection and then applied for cultivar registration as 'Murasaki-Zukin 3gou' in February 2015 [62].Growth characteristics such as flowering time, harvest time, and main stem length were comparable to those of the recurrent backcross parent, Murasaki-Zukin.
KAFF has also completed a breeding program for a new cultivar to replace 'Natsudori-Tambakuro 2gou' to prevent the early yellowing of pods and SMV infection [63].
Regarding pepper, sales promotion of Manganji began in the 1990s.Although it is sold as a traditional Kyoyasai sweet pepper (Fig. 4), the variety sometimes generates pungency.Therefore, KAFF first selects extremely low-pungency lines and pure breeds them with another culture.The line was registered as the cultivar 'Kyoto Manganji No.1 (Kyoto manganji-ichigou)' [64].To achieve a completely non-pungent pepper and eliminate some unfavorable traits from Kyoto Manganji No.1, Kyoto Manganji No.2 was bred using backcross breeding with marker-assisted selection of the non-pungent recessive gene.In the new cultivar, pungent fruits were completely eliminated, and other undesirable fruit characteristics (anthocyanin accumulation in the pericarp and short fruit length) were found at very low frequencies compared to Kyoto Manganji No.1 [65].The Japan Agricultural Cooperatives, 'JA Ninokuni, ' in Chutan adopted this cultivar and registered the area and the brand name 'Manganji-amato' as a Japan's geographical indicator (GI) starting in 2017 [66].
Ebi-imo is very popular as a delicious taro, and it is sold at approximately three times the price of ordinary taro.However, as it is a late-growing variety with a low yield, and soil filling and harvesting are difficult, this has resulted in a decline in the cultivation area.
Therefore, KAFF-selected lines were intended to create an early maturing, high-yielding, egg-shaped cultivar with many tubers.A new early maturing, high-yielding cultivar with 50% more tubers than the local lines due to its large tubers was then bred.It also produces eggshaped secondary tubers, which are suitable for 'Koebichan' shipment (30-70 g tubers).The new cultivar was subsequently released as 'Kyoto Ebi-imo 1gou' [76].The cultivar was then used to generate variations during culture de-differentiation and further improve its yielding ability.The selected line is called 'Kyoto Ebi-imo 2gou.'

Augment immune functions
Secretes mucus in the cavities of its green leaves Ueda et al. [98] wholesale markets in each region in Kyoto prefecture.
In terms of the functionality of Kyo-yasai, some have higher bio-antimutagenicity than common vegetables (Table 5) [56,77].Examples include eggplant, Japanese radish, pickling melon, and pumpkin [57,78].Edamame cultivars contain several unique ingredients.The production, composition, and functional properties of each variety of Kyo-yasai are detailed below: Mizuna contains three aroma components, 3-butenyl isothiocyanate, 3-phenylpropionitrile, and phenylmethyl isothiocyanate, and the antimutagenic effects of these components were identified.However, yearround cultivation in vinyl greenhouses has revealed seasonal variations in the amount of these components, and traditional open-field cultivation is known to be more suitable when these components are desired [52].
The soybean cultivar Murasaki-Zukin is an immature black soybean grown in Kyoto.This cultivar is rich in oligosaccharides, such as raffinose and stachyose, compared to ordinary soybean cultivars.Shin-Tanbaguro, the parent cultivar of Murasaki-Zukin, also has the highest maltose content, and related cultivars such as Murasaki-Zukin 2go contain higher maltose than the typical edamame cultivar Fuki [103][104][105].
Eggplant contains acetylcholine, a neurotransmitter that is expected to be a functional food material.When 19 vegetables and fruits were analyzed for this component, the concentration in eggplant was 2900 times higher than the average value for vegetables and fruits [106].In terms of bio-antimutagenicity, 'Kamo-nasu' showed higher levels than common eggplant based on their extracts against UV-induced mutation of E. coli [56].
Katsura-uri (pickling melon) contains the odorant compound 3-methylthiopropionic acid ethyl ester in its ripened fruit, suggesting its medical use [107].As this ingredient has a melon-like aroma, it can also be used as a non-sugar beverage and dish [108][109][110].Another compound, methylthioacetic acid, has been shown to improve glucose metabolism and acidification in skeletal muscles during exercise in both human and animal studies [111].
Pumpkin pulp has a high carotenoid content, especially lutein, which is the most abundant carotenoid in many varieties [112].The profile of bioactive compounds in pumpkin pulp is considerably diverse.The literature has revealed that Shishigatani-kabocha contains the highest content of gallic acid and protocatechuic acid among the 15 cultivars [113].Other studies have also reported that the protocatechuic acid content of the Shishigatani cultivar was second only to that of Kogiku, and for caffeic acid, it was the highest among the 20 cultivars in Cucurbita species [114].
The functionalities and ingredients of other vegetable species are summarized in Table 5.

Conclusion
Efforts such as the definition and selection of traditional Kyo-yasai, as well as sales promotion of the branded Kyoyasai [115], have played a pioneering role in promoting regional vegetables across Japan [48] and increasing consumer interest in heirloom vegetables.As a result, efforts to rediscover heirloom vegetables in other regions have accelerated [116].In recent years, the Ministry of Agriculture, Forestry, and Fisheries has also begun a survey of the production status of regional specialty vegetables since 2000 [117].It is currently attempting to construct a database of heirloom varieties owned by local governments and municipalities through PGRAsia, a commissioned project conducted by NARO Genebank [118], thus encouraging the preservation and utilization of regional vegetables.To continue this work in the future, it is necessary to improve these heirloom varieties and popularize them further, while public institutions need to continue to preserve the seeds.Maintaining the character of these heirloom varieties without changing the taste, functional ingredients, and appearance of the vegetable will be considered as contributing to the diversity of species and food culture in general.

Fig. 2
Fig. 2 Indigenous species of Kyo-yasai.a Japanese Butterbur, b the petiolar part is mainly edible; c shaded soft-grown Udo ginseng; d shaded soft-grown Mioga ginger; e water dropwort in paddy fields (upper), straw-covered water dropwort seedlings (center), f water dropwort harvested for a fair.Source Photos a and b were taken by the author.Photos c, d, e and f by the Kyoto Prefectural Institute of Agriculture, Forestry and Fishery Technology Center (KAFF)

Fig. 3
Fig. 3 Harvested Mizuna and Mibuna.a Mizuna has a pinnatisect leaf type, while b Mibuna has simple spatulate leaves.Source Photos by KAFF

Fig. 4 Fig. 5
Fig. 4 Harvested Kujo-negi and the literature explaining the origin.a Kujo-negi and b Section explaining the origin of Kujo-negi cultivation in the Kyoto Gardening Handbook (Kyotofu-Engeiyokan), published in 1909; the area circled in red explains the origin.Source Photo a by KAFF.Photo b is part of reference [20], stored at KAFF

Fig. 8 Fig. 9 aFig. 10
Fig. 8 Suguki plant and the production of pickles using it.a Suguki plant; b Suguki after pretreatment; c salt treatment; d pickling process in barrels (right) with load (left).Source Photos by KAFF

Fig. 11
Fig. 11 Kyoto vegetables of the Edo period depicted in the painting of 'Kaso-Nehanzu.' This painting was depicted by Jakuchu Ito (1716-1800); The area enclosed in red is Shishigatani pumpkin

Fig. 12
Fig.12 The proposal for a preservation list of Kyo-yasai by the Kyoto prefecture government in 1960

Fig. 13
Fig.13 Genealogy of the cultivars that make up the product brand names 'Murasaki-Zukin' and 'Kyonatsu-Zukin' .'Murasaki-Zukin': Four cultivars marked with * were harvested and shipped in the relay.'Kyonatsu-Zukin': One cultivar marked with ** was harvested and shipped under the trade name

Table 1
List of ancient pieces of literature before Edo-era(-1602)

Year of issue Title Contents Mentioned vegetable species
This book was written by Fukane no Suketo.It describes the aliases, Japanese names, and localities of the drugs listed in "Shinshuhonzo" and other Chinese herbalists' books Udo ginseng, Brassicaceae leaf vegetables, Burdock, Cowpea 931-938 Wamyorui-Jusho Dictionary created in the mid-Heian period Arrowhead 1005 Shui-Wakashu The third imperial anthology of waka poetry after Kokin and Go-Sen Pickling melon

Table 2
Indigenous species of Kyo-yasai and their cultural method and history

Table 3
The proposal for a preservation list of Kyo-yasai by the Kyoto prefecture government in 1960 *Later, these varieties were registered as Traditional Kyoto-yasai in 1987

Table 5
Food functionality of some vegetable species which include traditional Kyo-yasai