Cultivation techniques of smooth-skinned papaya and seedlings in Caozhou

Cultivation techniques of smooth-skinned papaya and seedlings in Caozhou

The Records of floating Life in the Ming Dynasty recorded: "there are papayas in return for peaches and plums, and three thousand things grow old." Caozhou Guangpi papaya is one of the three characteristic seedlings (Caozhou Guangpi papaya, Caozhou peony and Caozhou mirrored persimmon) in Heze City, Shandong Province. It has been cultivated in Heze for nearly a thousand years. As early as the Ming Dynasty has been well-known at home and abroad, the Ming and Qing dynasties, Heze papaya as a tribute into the capital, also enjoyed a high reputation in the society.

1 Biological characteristics and economic value of Caozhou light-skinned papaya

1.1 Biological characteristics and phenological phase

Caozhou light-skinned papaya belongs to the rose family papaya genus, is a deciduous tree, 5-10 meters high, more than 3-year-old trunk and bark flaky peeling, flowers solitary, flowers stick branches. There are more than a dozen varieties of papaya in Caozhou, which vary greatly with a single fruit mass of 0.32kg. There are mainly bean green, magnolia, flowering, fine skin, bergamot, big and small lion head, peony papaya and other varieties. Light-skinned papaya is not strict on the soil, the pH value of 5.5-8.3 can be normal growth, the most suitable soil is neutral sandy loam. Caozhou light-skinned papaya is cold-resistant, heat-resistant, drought-resistant and waterlogging-resistant. It can grow at extreme temperatures of-29.8 ℃ in Beijing and 43.7 ℃ in Heze. As long as the low temperature of 0707 ℃ is 30 days, it can meet the low temperature requirement of Caozhou light-skinned papaya, and it will grow and blossom and bear fruit normally in the following year. In Caozhou, Heze City, Shandong Province, the buds sprouted in mid-March, flowered in mid-April and Xie in late April. The flowering period was 15 days, and it could self-blossom and bear fruit. Due to different varieties, it matured from late September to early October and deciduous leaves in late November.

1.2 Economic value

Caozhou light-skinned papaya is known as "Baiyi fruit king" and "longevity fruit". The tree is beautiful, the branches are vigorous, the spring and summer flowers are in full bloom, the golden fruit is full of trees after autumn, and it is fragrant and fragrant, which integrates ornamental, greening, medicinal and edible. It has always been known as a famous ornamental tree and a rare garden and economic tree species. You can watch it all the year round, dark green in summer and orange in late autumn

The effect of greening and beautification is unique, and it is one of the ideal colored leaf tree species in the garden. Spring season, or the first leaves and flowers, or flowers and leaves. The varieties of flowers and colors are red, pink, white and so on. The skin of papaya is smooth and delicate, the young fruit is green and fragrant, the fruit ripens gradually after autumn (figure 1), the fruit becomes golden and shiny, the fruit is large and dignified, with elegant rich and unique natural fragrance, it can keep fragrance for more than 5 months, it is refreshing, the bark is flaky, the trunk is smooth and mottled, it can not only decorate the environment but also purify the air, it is a rare and rare ornamental fruit tree species in the garden. In the history of Caozhou light-skinned papaya fruit is mainly used in traditional Chinese medicine, the function is to relax meridians and activate collaterals, appetizer and spleen, soothing the liver and relieving pain, dispelling wind and dampness. Caozhou light papaya is rich in nutrients, the aroma of mature fruit is refreshing, and the fruit can be made into jelly, jam, candied fruit, preserved fruit, dried fruit, fruit tea, fruit wine, fruit Yee and so on. Good color, smell and taste, suitable for all ages, nourishing and nourishing beauty. In addition, it can also produce health care, makeup and other products.

Fig. 1 nearly mature Caozhou light-skinned papaya

2 cultivation techniques of smooth-skinned papaya seedlings

2.1 seed treatment

After the papaya fruit is ripe in October, the fruit will be ripe for a period of time after picking the fruit. In the middle and late November, cut the papaya longitudinally with a knife, take out the seeds, soak them in 0.3% (mass fraction, same as later) neutral washing powder for 1 hour or 2 hours, and scrub the mucus on the seed surface for 2 times. After soaking in clean water, rinse the detergent 3 times, drain it and dry it. It can be broadcast in November. The seeds can also be stratified and sown at the beginning of March of the following year.

2.2 seed sand storage treatment

Caozhou light-skinned papaya seedlings are mostly cultivated by grafting, and seeds are generally stored in sand in mid-December. Papaya seeds are removed from impurities, diseases and insect pests, blighted seeds, mildew seeds, and then dried for 3 days. The seeds were soaked in 3% potassium permanganate solution for 30 minutes, washed with clean water for 2 times, soaked in clean water for 24 hours to make the seeds absorb enough water, and then removed and leached. The soaked wet seeds were mixed with the wet sand. Before mixing, the sand was sifted and washed with clean water. The humidity of the sand should be kept by holding hands and loosening hands. The m ∶ m sand was 1 ∶ 5. Mix the seeds and wet sand into a woven bag, dig a storage ditch 40 cm deep, spread a layer of 15 cm thick wet sand at the bottom of the ditch, and then put the bag containing sand into the ditch. Every 1 meter or so, put a handful of straw made of sorghum straw vertically between the two bags, all the way up to 20 cm above the ground, as an air vent, and then cover the seed bag with 20 cm thick wet sand, and finally seal it into a roof ridge shape. In the process of seed stratification, we should check frequently and pay attention to the temperature and humidity of planting sand. if we find dry or uneven dry and wet, we should properly add water or take out the bag and turn it upside down. if moldy seeds are found during the inspection, we should remove them in time. If the temperature rises after the Spring Festival, we should increase the inspection times. If it is found that the seeds begin to germinate and it is still early before the sowing time, the seeds should be moved to a place with lower temperature to restrain germination and prepare for sowing immediately. The seeds can be sown when 30% of the seeds begin to show white.

2.3 soil preparation and sowing

Select the land with high dryness and good drainage to plant pH6.5~7.5, and it is better to use fertile and loose sandy loam. In Heze, it is generally possible to sow seeds in early March. Before soil preparation, if the soil moisture is poor, it should be watered in February to make soil moisture, and soil preparation should be carried out at the beginning of March. 5000 kg of mature farm manure and 50 kg of compound fertilizer should be applied per mu. Ferrous sulfate 50 kg, phoxim granule 15 kg and carbendazim 5 kg per mu were applied as soil insecticides, and the soil was deeply raked and leveled to form a high border, with a height of 20 cm 30 cm, a width of 120 cm, a length of not more than 30 cm, and a 30 cm aisle between the two beds. it is better to choose north-south strip sowing, using wide and narrow rows, 40 cm wide and 20 cm narrow rows, ditching according to row spacing, ditch depth 2 cm 3 cm. Spread the seeds and wet sand evenly into the ditch, then cover 1.5 cm of fine soil, then cover with agricultural plastic film and compaction. Use 5 kg of seed per mu.

2.4 Seedling stage management

The plastic film should be removed in time when the seedlings are unearthed 10% ~ 20%. When 50% seedlings are unearthed, 0.1% 0.125% Bordeaux solution is sprayed every 7 to 10 days to control the seedling quenching disease. When the seedlings come out, spray 0.1% 0.125% Bordeaux solution (mass fraction, the same later) or 50% carbendazim 0.13% solution every 7 days, twice in a row, when leaf pests occur. 4.5% pyrethrin EC 0.07% solution can be sprayed for prevention and control. When there is harm to underground pests, 50% phoxim EC 0.1% solution can be used for control. The seedlings began to grow between seedlings when they showed 2-3 true leaves, and when 4-5 true leaves were fixed according to 10 cm plant spacing, it was appropriate to keep 8 000-10 000 seedlings per mu. After setting the seedlings, when the seedlings grew to 5-6 true leaves, 0.1% urea was used to topdressing them for 2 times. When the seedlings grew to 8-10 true leaves, a small amount of diammonium phosphate was applied to the roots, about 15 kg per mu, and 20-30 kg urea per mu after 30 days. Watering after fertilization, generally no longer topdressing after late August, to prevent the vigorous growth of autumn shoots, postpone the defoliation period, easy to freeze shoots in winter and spring, ploughing and weeding in time. When the thickness of the rootstock is more than 0.5 cm, it can be grafted.

2.5 grafting

2.5.1 T-shaped bud grafting selects the full and robust branches of the same year as scions, cuts off the leaves on the branches and retains the petiole. Take the scion in the left hand and the bud knife in the right hand. In the upper 0.3 cm to 0.4 cm of the bud, cut horizontally with a bud knife, reaching to the xylem, and then slash upward 1 cm below the bud to the xylem until it meets the incision above the bud. Then gently remove the shield-shaped bud with the right hand, with a little xylem in the bud, and select the smooth part of the stem where the rootstock is 5cm away from the rhizosphere, cut across it, cut the cortex of the rootstock at a depth, and cut it vertically down from the middle of the cross-section, with a length of 1.3cm and 1.5cm, so as to form a T-shaped incision. Cut open the cortex of the rootstock with a budding knife, then insert the bud into the incision of the rootstock immediately, pay attention to the epidermis of the bud should be close to the transverse incision of the rootstock, and cover the buds with the cortex of the rootstock previously picked. Use plastic tape to bind from the top, gradually wrap it down, expose buds and petioles, do not leave gaps in other places, and finally tie a knot. The binding should be loose and tight, and do not crush the bud.

2.5.2 if split grafting does not survive bud grafting, split grafting can be carried out before germination in March of the following year. Caozhou smooth bark branches, a 1-year-old fine variety, were selected as scions. For rootstocks with a thickness of more than 0.5 cm, cut at 5 cm and 10 cm above the ground, trim the incision, cut 1 knife longitudinally in the incision, the cut length is about 2.5 cm, select the scion with the same thickness as the rootstock, the scion length is 10 cm 12 cm, retain 2 full buds in each segment, symmetrically cut two knives under the scion, and make one side thinner. Make it wedge-shaped, the incision should be smooth, and the cut is about 2 cm long, then insert the cut scion into the rootstock to align the cambium of the two (which is the key to the survival of the grafting), and then bind the wound with plastic sheet. finally, the upper end of the scion is cut.

(3) check survival, release of binding and cutting anvil

The "T" type bud was tested to survive after 15 days, and gently touched the petiole with your hand, such as it fell, indicating that it had survived. As long as the bud mouth remained fresh green, there was hope of survival. If you can't touch it, the bud will dry up, which means the grafting failed. The light-skinned papaya in Caozhou, which was split in spring, was unbound around June, not in the year of bud grafting in autumn, and unbound when cutting the anvil in early spring the following year.

(4) sprouting and de-sprouting

For those who survive the grafting, the buds and root tillers on the rootstock should be erased in time, so as to reduce nutrient consumption and promote bud germination and growth. Sprouting and tillering must be carried out many times before they can be cleaned up. Before sprouting in spring, cut the anvil at 1-1.5 cm above the bud, and the cross section should be tilted to the opposite side of the bud [Jishan Huayao].

5 Fertilizer and water management and pest control

Watering once about 7 days before grafting, grafting is easy to survive, 30 kg of compound fertilizer per mu before germination in early spring, watering after fertilization, timely ploughing and weeding, disease and pest control, to ensure the healthy growth of seedlings (figure 2, figure 3).

Fig. 2 Caozhou light-skinned papaya nursery

Fig. 3 4-year-old Caozhou smooth papaya orchard