Characteristics: Watermelon has a main root system, the depth of which is more than 1 m, and the root groups are mainly distributed in the 20 cm-30 cm plough layer. The roots are slender, easily broken, weak in regeneration and not resistant to transplantation. The stems of seedlings stand upright, elongate after 4-5 internodes, crawl after 5-6 leaves, and have strong branching ability, which can form 3-4 levels of lateral branches. Leaves alternate, deeply divided, shallowly divided and entire. Dioecious flowers are the same plant. Male flowers appear in the 3-5 nodes of the main stem, and female flowers appear in the 5-7 nodes. A few bisexual flowers can appear at flowering stage. Corolla yellow. The ovary is below and the placenta is the lateral membrane. Both male and female flowers have nectaries, and the flowers are insect-borne flowers, which open in the morning and close in the afternoon. Fruits are spherical, oval, oval, cylindrical and so on. The surface of the fruit is smooth or ribbed, and the epidermis is green-white, green, dark green, dark green and black, with fine meshes or stripes in between. The pulp is milky white, light yellow, dark yellow, light red, bright red and other colors. Meat is divided into meat and mortar. Seeds flat, ovoid or oblong, smooth or cracked. The seed coat is white, light brown, brown, black or brown, monochrome or variegated. The 1000-grain weight is 100g- 150g for large grain type, 40g-60g for medium grain type and 20g-25g for small grain type. Melon type 150g-200g.
Watermelon planting likes high temperature and dry climate. The suitable growth temperature is 25 ~ 30℃, and 6 ~ 10℃ is vulnerable to cold damage. In areas where the monthly average temperature is above 65438 09℃ and the annual average temperature is above 3 months, it is feasible to cultivate in the open field. It is a long-day plant, which likes strong light, and its light saturation point is 80,000 lux. Suitable for dry and hot climate, strong drought tolerance, sandy loam with good drainage and deep soil layer. The pH value of the soil is 5 ~ 7. There are many ways to grow watermelons in China. There are dry pond cultivation and shatian cultivation in northwest China, flat border cultivation in north China and high border cultivation in south China. Protected areas include windbreak cultivation in Beijing, reed hair cultivation in Baoding, plastic film mulching cultivation, plastic greenhouse cultivation and greenhouse cultivation. Whether cultivated in open field or protected field, seedlings are raised in the protected field in spring before planting. Organic fertilizer is the main base fertilizer, and calcium superphosphate and potassium sulfate can improve the sugar content of fruit. The planting density is generally 500 ~ 600 plants per mu. North China is pruning, one plant, one vine and one melon; If you don't prune in South China, you will get more vines and melons. It takes about 80 ~ 120 days from sowing to harvesting, and about 30 ~ 50 days from female flower opening to fruit ripening. The main diseases are Fusarium wilt, anthracnose and powdery mildew. The main pests are aphids, flies and melons.
Origin most parts of the country can be cultivated. There are a lot of cultivation in Laixi, Shandong Province. Nanlan watermelon is produced in Hetoudian Town, Laixi City, and is famous for its thick pulp, sweet taste, rich moisture and rich nutrition.
Watermelon is the main fruit in summer. Mature fruit contains a lot of water, and the sugar content of pulp is generally 5 ~ 12%, including glucose, fructose and sucrose. The sweetness increased with the increase of sucrose in the late mature stage. There is almost no starch, and the sweetness will decrease due to the hydrolysis of disaccharide into monosaccharide during storage. Melon seeds can be used as tea, and melon skin can be processed into watermelon sauce. Chinese medicine uses melon juice and peel as medicine, which can clear away heat and relieve summer heat.
Also known as summer melon and cold melon, it is called the king of melons. Because it was introduced from the western regions in the Han Dynasty, it was called watermelon. Watermelon also belongs to the genus Cucurbitaceae, which is native to Africa. At present, except for a few remote and cold areas, it is planted all over the country, and the fruit is sweet and cold.
Watermelon is a typical fruit and the main fruit in summer, so we should cherish it more.
In hot summer or hot tropical night, as long as there is frozen watermelon, it has the effect of cooling off the heat.
Variety: Watermelon can be divided into three categories according to different uses: ordinary watermelon, melon seed melon and small watermelon.
China is the largest watermelon producing area in the world, but watermelon is not native to China. Watermelon originated in Africa. It was originally a wild plant of Cucurbitaceae, which was cultivated artificially to become an edible watermelon.
As early as 4000 years ago, Egyptians planted watermelons, and then gradually moved northward, first from the Mediterranean coast to northern Europe, and then south to the Middle East, India and other places. In the 4th and 5th centuries, watermelon was introduced into China from the Western Regions, so it was called "watermelon".
According to Xu Guangqi, a scientist in the Ming Dynasty, the book "The Complete Book of Agricultural Administration" records: "Watermelon is named after being planted in the western regions." Li Ming's Compendium of Materia Medica records: "According to Hu Jiao of Uighur, there is a kind of melon called watermelon. Watermelon entered China from the Five Dynasties; There are north and south today. " Thus, watermelon cultivation in China has a long history.
How to get seedless watermelon
Now seedless watermelons cultivated in production are all triploid watermelons. It is a first generation hybrid produced by crossing tetraploid (4X) watermelon as female parent and diploid (2X) watermelon as male parent. Now seedless watermelons are not completely seedless, and there are undeveloped small white seed coats like tender cucumber seeds, which taste seedless, so they are called seedless watermelons.
Other methods of producing seedless watermelon
1. natural hormone method
According to the characteristics of parthenocarpy of watermelon, this method stimulates the ovary of seedless diploid watermelon by using the natural hormones contained in the flowers of tetraploid watermelon with few seeds, so that the fertilization process does not occur. Through its inherent physiological function, ordinary (diploid) watermelon plants are urged to set fruit and grow into seedless watermelon, which is a new way to produce seedless watermelon quickly. It has the characteristics of easily available raw materials, simple method and convenient operation. Seedless watermelons can be produced that year, and the fruit shape is correct, and the skin is thin and not hollow. Watermelon has the same texture and flavor as the original common watermelon variety, and no special cultivation measures are needed from growth to maturity, thus avoiding the problems of low germination rate, low seedling rate and low seed setting rate of seedless watermelon.
The experiments of Hubei Academy of Agricultural Sciences for many years have proved that the seedless watermelon produced by this method is similar to the triploid seedless watermelon, and the fruit only contains white, tender and edible seeds, with an inclusion of 9% ~ 10%, and the peel thickness and flavor are the same as those of the selected common watermelon varieties. The results showed that seedless watermelon with Xingcheng Red as the female parent was the best, with thin skin, crisp meat, high sugar content, good flavor and few white seeds. Seedless watermelon produced with Mi Bao Hedu No.3 watermelon as female parent is the second, and the specific production technical points are as follows:
(1) Choose a good parent: the watermelon with few seeds selected as the male parent requires a variety with many seeds in the fruit and good pollen quality, and requires the healthy growth of the plant. The common watermelon selected as the female parent requires varieties with few seeds, thin skin, high sugar content and good quality in the fruit, and requires the healthy growth of the plant.
(2) Timely pollination: No matter the male flowers selected as the male parent or the female flowers selected as the female parent, they should be bagged or bundled manually in the afternoon before flowering. The next morning, when the male and female flowers are in bloom, the male flowers are picked in time, the bagging or binding is lifted, and the female flowers are artificially pollinated. Pollination should be sufficient and careful to avoid damaging female flowers. After pollination, the female flowers are still bagged or bundled to prevent the pollen of ordinary watermelon from falling on the stigma. Generally, after 3 days of pollination, young melons should be bagged in time when they sit down to promote their normal growth and development.
(3) Rejecting heteromorphic melons: In Gua Tian, where natural hormones are used to produce seedless watermelons, after the melons are seated, you should stay and inspect Gua Tian, and promptly reject the naturally seated melons without artificial pollination to prevent the generation of heteromorphic melons and seedless watermelons. Otherwise, due to the strong competitiveness of ordinary watermelons and weak competitiveness of hormone watermelons, young watermelons will not grow up and will not become melons.
(4) Strengthen fertilizer and water management: Because the seedless watermelon stimulated by natural hormones is developed from unfertilized embryos, its growth and development are fragile, so it is necessary to give good fertilizer and water conditions, strengthen vine arrangement and promote its normal growth and development.
(5) timely harvesting: the seedless watermelon produced by this method is suitable for harvesting about 30 days after flowering, with early maturity, low sugar content and poor quality; If the fruit is harvested too late, the seeds in the fruit will increase and affect the taste. Picked seedless watermelons should be sold or eaten immediately, and it is not easy to store them for a long time, otherwise the seeds in the fruit will harden and the quality will deteriorate.
2. Synthetic hormone method
Practice has proved that artificial induction with some hormones can also make common diploid watermelons bear fruit. The watermelon formed has only a white seed coat and no embryo, and tastes like seedless watermelons. The specific production points are as follows:
(1) Selection of excellent varieties: Experiments have proved that Zaohua is an excellent variety of seedless watermelon produced by artificial synthetic hormones at present. When other measures are taken, the seedless watermelon rate can reach 90%, which is basically the same as that produced by artificial pollination of this variety. Other varieties, such as Zhengzhou No.3, Lemi 1, Zhongyu No.6 and Luxigua 1, are also better.
(2) treatment method: firstly, distilled water is used to prepare 100ppm sodium naphthylacetate, 25ppm gibberellin and 25ppm 2,4 ~ d respectively. Then, the female watermelon flower was treated with the same amount of mixed solution of these three solutions (mixing ratio:1:1). The mixed solution shall be prepared as required and used up on the same day after mixing. Ten thousand ways to deal with female flowers are to bag or clip flowers in the afternoon before the female flowers open (if they are bisexual flowers, they should be strictly castrated). When the female flowers open the next morning, take off the bag or bundle and dip it in the mixed solution with a new brush and apply it to the stigma and ovary base of the female flowers. The dosage of each flower is about 1 ml. After application, the corolla must still be clamped or bagged for protection. Taking off the bagging on the fourth day after application, spraying the mixed solution at one time or spraying 20ppm of cytokinin 6 ~ furacilin solution have obvious effects on improving the maturity rate of melon. Experiments show that it is most ideal to treat the second female flower of the main vine (double vine pruning). The application should be made on a sunny day. If it rains after application, it should be reapplied 1 time after rain.
(3) Fine field management: plants should be robust before flowering. After coating, the lateral vines and growing points at the axils of the main vines should be pinched off immediately, and the melon vines should be pressed well to promote the transport of nutrients into the melons. After the first application, if it is found that the skin of the young melon is dark, it should be applied again 1 time, which can effectively prevent the melon from melting. After the first application 10 days, the growing point of the second melon vine can be pinched off. Don't raise young melons that haven't been treated with chemical solution on two vines of the same plant, because there are seed melons and seedless melons on the same plant at the same time, and the nutrients are easily competed by seed melons, which will lead to seedless melons becoming melons. It is necessary to remove other female flowers in time to prevent seed melons from setting. After the first coating treatment 12 days or so, when it is safe, it is necessary to water and topdressing. However, the amount of watering should not be too large, and a small amount of water should be poured frequently. Generally, water 3 ~ 4 cubic meters per mu once, and every 2 ~ 3 days. Topdressing should be ditched on one side of the plant and 30 ~ 40 kg of ternary compound fertilizer should be applied per mu.
3. Cutting cultivation method
See the section "Cutting Cultivation" for details.
4. Tissue culture method
Tissue culture is a new propagation method that uses a certain part of plant tissue or organ to cultivate a complete plant under aseptic conditions. China started this work from 65438 to 0979. At present, many units in Shanghai, Beijing, Shandong, Hebei, Shanxi, Gansu, Heilongjiang and other provinces and cities have produced a large number of seedless watermelons with high quality and high yield for the market by this method, and achieved remarkable economic and social benefits. The specific method is:
(1) Culture materials: According to reports at home and abroad, the seed embryo, stem tip, root tip, pollen and ovary of watermelon can all be used for tissue culture, but the seed embryo and stem tip tissue culture are the most widely used at present.
(2) Culture medium: The materials and culture stages of watermelon tissue culture genes are different. Generally, it can be divided into three kinds: bud differentiation medium, embryo medium and rooting medium.
① Watermelon bud culture medium: Every liter of culture medium contains 500 mg of ammonium nitrate (NH4NO3), 65,438+0,000 mg of potassium nitrate (KNO3), 440 mg of calcium chloride (CAC 65,438+02), 370 mg of magnesium sulfate (MGSO 4·7h2o) and 370 mg of potassium dihydrogen phosphate (KH2PO4). There are ferrous sulfate (feso 4·7H2O)55.7g, manganese sulfate (mnso 4·4H2O)22.3mg, boric acid (h3bo 3)6.2mg, potassium iodide (KI)0.83mg, sodium molybdate (Na2MoO4 7H2O) 0.5mg； and zinc sulfate (ZnSO4 7H2O) 8. Contains the hormones IAA1mg and 6- benzylpurine (6-BA)0.5 mg; Contains 7 grams of agar, 30 grams of sucrose or 50 grams of edible sugar. Adjust the pH value to 5.5 ~ 6.4.
② Watermelon embryo culture medium: Macroelements, trace elements, vitamins and organic matter are the same as ①, but the hormone does not contain IAA and 6- benzylpurine (6-BA). Sugar is changed to 20g per liter (33.3g of edible sugar). Adjust the pH value to 6 ~ 6.4.
③ Watermelon rooting medium: except for removing hormones 6- benzylpurine and indoleacetic acid in ①, indolebutyric acid (IBA) 1mg was used, and other elements were exactly the same as those in ①.
(3) culture method: firstly, the culture material is sterilized. If the material is seeds, first soak the seeds in warm water at 70 ~ 80℃, stir to about 30℃, soak for one day and night, then disinfect with 75% alcohol for 30 seconds, peel off the seed coat under aseptic condition, disinfect with 0. 1% mercuric chloride for 2 minutes, then rinse with sterile water for 4 ~ 5 times, inoculate on the culture medium, and put in the culture room for culture. The radicle germinated first, and two weeks later, when the two cotyledons unfolded and turned green, the germ with the leaves was cut off and transferred for culture. Cut once every 3-4 weeks, separate the terminal bud from the lateral bud, and then subculture.
If shoot tips or lateral buds are directly taken from triploid watermelon seedlings in the field, they are first washed with tap water, then disinfected with 75% alcohol for 10 second, then disinfected with 0. 1% mercuric chloride for 2 minutes, finally washed with sterile water for 4-5 times, inoculated on the culture medium and cultured in the culture room.
(4) Medium and culture conditions: The basic medium used is M5 and 1/2MS. According to the specific requirements of seedling differentiation, growth and rooting, different hormones, 3% sucrose and 0.7% agar were added to adjust the pH value to 5.8. Sterilizing at high temperature for 20 minutes under the pressure of 65438 0 kg/cm2, then inoculating, and then culturing the inoculated explants in a culture room with the temperature of 26 65438 0℃, the illumination intensity of 65438±0000 lux and the illumination of 65438 04 hours/day.
(5) Grafting and management: Bud seedlings proliferated by tissue culture can be directly cultivated into mature seedlings for production, or can be grafted into grafted seedlings for production, and the latter is better. If grafted seedlings are cultivated, differentiated buds need to be heightened before grafting. The method is to transfer the bud seedlings to MS+IBA 0.5 ~ 1.0+GA 0.5 rooting medium without kinetin, so that the base of the bud seedlings gradually takes root. With the growth of roots, the young stems grow rapidly and develop healthily, which improves the quality of scions. The rootstock for grafting is planted in a plastic nutrition bowl filled with ordinary soil. When the cotyledons of the rootstock are unfolded and the true leaves are slightly exposed, the top buds of the rootstock are cut off for grafting. Please refer to the section "Grafting Cultivation" for the selection of rootstocks and grafting operation methods. Immediately after grafting, the grafted seedlings were transferred to the healing shed for healing. The temperature in the shed is 25 ~ 35℃ and the relative humidity is above 95%. Under these conditions, the grafted seedlings can heal in about 65,438+00 days, and then move to the greenhouse for 3 ~ 4 days. During this period, we should pay attention to ventilation and gradually enhance its adaptability. Finally transplanted into the field. Field cultivation management measures are similar to seedless watermelon cultivation management measures, which can be implemented by reference.
When was watermelon introduced to China?
Watermelon, native to Africa. Watermelon has been planted in Egypt for five or six thousand years. In the past, some people quoted Ouyang Xiu as saying in the appendix of History of the New Five Dynasties and Four Differences in Song Dynasty: In Heyang County, Tongzhou, Hu Jiao was ordered to "eat watermelon first" in Qidan; "When Qidan broke the Uighur, it was planted in a shed, and the shed was covered with cow dung, which was as sweet as China wax gourd"; "It was three years old (953) ...................... 198 1 The extracurricular reading of middle school students published by Hunan People's Publishing House has a section "Watermelon began in the Five Dynasties". In fact, this statement is not accurate
Li Shizhen in Ming Dynasty pointed out in Compendium of Materia Medica: Watermelon is also called cold melon. "Tao Hongjing (Southern and Northern Dynasties) notes that there is a big cold melon in Yongjia (Huaidi Year), which can be hidden until the sound of spring, that is, this is also. Five generations ago, melon seeds had entered eastern Zhejiang, but they did not have the name of watermelon and did not spread throughout China. " "The Legend of Teng Tan Gong" said that Tan Gong was "five years old, and his mother Yang suffered from fever, thinking about eating cold melons, and the local customs were not productive. It's sad that I can't get visitors through the calendar. I met a Sangmen and asked him why, so I was ready to tell him. Sang Men said, "I have two melons, one for each person." I am also surprised by my mother. I am looking for Sang Men, and I don't know where it is. In the Tang Dynasty, Volume 19 of Youyang Za recorded the poem Hangyuan written by Yin Hou (Shen Yue): "Cold melons lie on the long side, and autumn pu is full of bitterness. Purple eggplant rotten, green taro uneven. "Speaking of the melon lying in the poem, it is in line with watermelon. In addition, in old Beijing, watermelons listed first are called "watermelons", and those listed later are called "cold melons". Today, I visited the old farmer and said that late-maturing watermelons are indeed called "cold melons". The above documents seem to confirm Li Shizhen's statement. But it seems that Li Shizhen's statement has not attracted people's attention for hundreds of years. 1976, watermelon seeds were found in the silt of the Western Han Tomb in Gui County, Guangxi. 1980, watermelon seeds were found in the lacquer warehouse of Han tomb in Hanjiang County, the western suburb of Yangzhou, Jiangsu Province. The owner of the tomb died three years before Emperor Xuandi of the Han Dynasty (7 1 year). This irrefutably proves the reliability of Li Shizhen's record.
Watermelon, as its name implies, is a melon from the western regions. Five dynasties ago, it was not called watermelon because it had been introduced to the southeast coastal areas of China. Because of its cold and antipyretic nature, it was called cold melon. Therefore, it seems doubtful that watermelon was introduced into China from the Western Regions. So, how did it enter China?
The author speculates that it was introduced into China by the Maritime Silk Road. Emperor Wu of the Han Dynasty once sent "translators" to raise businessmen, take silk and go to western countries by boat. The ship set sail from Leizhou Peninsula, sailed along the west coast of Beibu Gulf and the coast of Vietnam, bypassed the southern tip of Vietnam, then went south along the coast of Malay Peninsula along Siam Bay, arrived in Singapore, turned west, crossed the Straits of Malacca and arrived in the country along the Bay of Bengal. " Chinese-English translation has paid off since then (Hanshu Geography); This sea route is the so-called "Maritime Silk Road".
Where is the "no country" today? Most scholars think it is Sri Lanka, while others say it is Abyssinia in eastern Africa. No matter which statement is correct, it shows that the sea passage of China-Africa traffic has been opened in the era of Emperor Wu of the Han Dynasty. Because in the Han dynasty, Arabs had mastered the secret of the Indian Ocean trade winds and were able to sail through the Indian Ocean from east to west. In this way, it is entirely possible for Sri Lanka and Nanyang Islands to become transit points between China and Africa. Watermelons from Africa can be introduced into China through Sri Lanka or Nanyang Islands. Watermelon seeds unearthed from Han tombs in Guangxi and Jiangsu are evidence of non-cultural communication in maritime Silk Road communication.
In addition, according to Guangming Daily on February 24th 1959, watermelon seeds were also found in the Neolithic site of Shuitianfan in Hangzhou, Zhejiang. If this archaeological harvest is really reliable, the history of watermelon in China is at least more than 4,000 years, and the saying that watermelon originated in Africa is another matter.