Detailed Explanation of the Key Points of Standardized Cultivation Techniques for Trichosanthes kirilowii
Trichosanthes kirilowii is also known as Trichosanthes, bitter melon (Yueqing), hanging melon (Wenzhou Wencheng), and old crow melon (Wenzhou). Its root (traditional Chinese medicine name: Trichosanthes root), fruit (traditional Chinese medicine name: Trichosanthes fruit), fruit peel (traditional Chinese medicine name: Trichosanthes peel), and seeds (traditional Chinese medicine name: Trichosanthes seed) belong to the Cucurbitaceae family, genus Trichosanthes, a perennial climbing herb, with a length of up to 10 m. The rhizome is thick and fleshy, cylindrical, with a yellow outer skin. The stem is much branched and hairless; the leaves are alternate, nearly circular or heart-shaped, and the species is dioecious; the male flowers are several in a raceme, rarely solitary, the corolla lobes are obovate, the female flowers are solitary, the ovary is ovate, the fruit is nearly spherical and orange-red when ripe, and the flowering and fruiting period is July to November.
The plant morphology of Trichosanthes kirilowii
Perennial climbing herb, more than 5 m long. The rhizome is thick and fleshy, cylindrical, with a yellow outer skin. The stem is much branched and hairless; tendrils are axillary, slender, with the apex 2—5-lobed. The leaves are alternate, nearly circular or heart-shaped, about 7—20 cm in both length and width, usually 5—7-palmately shallowly lobed or medially lobed, rarely deeply lobed, or not lobed and only with unequal coarse teeth; the lobes are oblong or oblong-elliptic to ovate-lanceolate, sparsely covered with short appressed hairs or hairless on the surface, with an acute or short acuminate apex, and the margin is sparsely toothed or incised. Dioecious; the male flowers are several borne on the upper part of a 10-20 cm long peduncle in a raceme, rarely solitary; the bracts are obovate or broadly ovate, 1.5-2 cm long, with toothed margins; the receptacle is tubular, about 3.5 cm long; the calyx lobes are lanceolate, entire, about 15 mm long; the corolla lobes are obovate with a thread-like apex; there are 3 stamens, the filaments are short and hairy, and the anthers are connivent; the female flowers are solitary, the ovary is ovate, and the style is 3-lobed. The fruit is nearly spherical, orange-red when ripe, and smooth; the seeds are numerous and flat. The flowering period is July—August, and the fruiting period is September- November. It is produced in various areas of southern Jiangsu and northern Jiangsu, growing on sunny slopes, at the foot of mountains, in rock crevices, and in field grass. It is distributed from northern China to the Yangtze River basin.
Standardized cultivation techniques for Trichosanthes kirilowii
1. Selection of soil layer
Deep, fertile, well-drained sandy loam; before freezing, plow the land deeply, level and harrow it finely, and dig trenches 50 cm deep and 30 cm wide at a row spacing of 1.5 m so that the soil weathers and matures. Before planting in the following spring, apply a total of 3000 kg per mu of compound fertilizer composted from decomposed barnyard manure, soil and miscellaneous manure, cake fertilizer, superphosphate, etc., into the trenches, mix well with the trench soil, then fill the trench surface level with fine soil, and immediately irrigate thoroughly along the trench. After 2-3 days, shallow plow once, and when the soil is moderately dry and wet, make beds and plant.
2. Sowing
Sowing is divided into seed propagation, tuberous root propagation, and vine layering propagation.
1. Seed propagation. The time for seed propagation by sowing can be chosen in early spring from late February to early March. Generally, direct sowing or seedling transplanting is used. For the seed source, use fruits harvested mature in September- October of the previous year and dried in a cool, ventilated place; as soon as the seeds are taken out, soak them in about 40°C 1% warm salt water for 4-6 hours, then transfer them to cold water and soak for 24 hours, take them out and drain the water, mix evenly with 3-5 times wet fine sand, and place them in a 25-30°C greenhouse to promote germination. Once most seeds have cracked and shown white, they can be sown.
1) Direct sowing. On the prepared planting land, apply an appropriate amount of decomposed compost at a row and plant spacing of 130×50 cm, mix and turn evenly with the hole soil, cover with fine soil 10 cm thick, then scatter-sow 5-7 seeds per hole with the seed tip or crack facing downward, cover with fine soil 2-3 cm thick after sowing, and cover with grass to keep warm and moist. After emergence, remove the covering grass, and when the seedlings are about 10 cm tall, thin them, leaving 2-3 strong seedlings per hole.
2) Seedling transplanting. It is advisable to use germinated seeds for hotbed seedling raising, which can be transplanted about 50 days earlier, prolong the growth period of Trichosanthes kirilowii, promote flower bud differentiation, and with good management, it can bear fruit in the same year. The method is: choose sunny sandy loam as the hotbed, prepare the land in early spring, make a bed 1.3 m wide, with the bed length depending on the terrain. Then, dig up the bed soil, fill in compound fertilizer composted from humus soil, compost, superphosphate, human and livestock manure, etc., about 30 cm thick, and cover with fine soil 10 cm. Around the Rain Water solar term, open horizontal furrows at a row spacing of 15-20 cm, 3-5 cm deep. Then, cover the bed surface with plastic film every 7 cm to keep warm and moist. By late March, when the seedlings have grown 2-3 true leaves, on the prepared planting land, dig holes at a row and plant spacing of 50×30 cm, with hole diameter and depth each 30 cm, apply sufficient base fertilizer, mix evenly with the hole soil, then fill with fine soil 10 cm thick, and then plant 2-3 seedlings or layered vine seedlings per hole, cover with soil and press the roots firmly. After planting, pour 1 light application of human and livestock manure water, about 1000 kg per mu, to promote survival.
2. Tuberous root propagation. Select excellent Trichosanthes kirilowii that has fruited for 3-5 years, grows robustly, and is free of pests and diseases, and an appropriate number of male plants (configured at 10 plants per mu). Around Qingming Festival, dig out the tuberous roots, select fresh tuberous roots with a diameter of 3-5 cm, a white cross-section, and no pests or diseases (those with yellow streaks in the cross-section are diseased roots), cut them into small sections 5-7 cm long as seed roots, dip the cut ends in plant ash (mixed with 50% calcium magnesium phosphate fertilizer), then spray with 0.51 PPM gibberellin (GAC dilute solution), let them dry slightly, and plant. On the prepared bed surface, at a row spacing of 1.5 m and a plant spacing of 30 cm, dig holes 9 cm deep, place 1 section of seed root in each hole, cover with fine soil 3-5 cm thick, press firmly with the foot, and then earth up 7-9 cm to form a small mound. Alternatively, cover with plastic film after planting, and after the seedlings emerge, promptly break the film and open holes to guide the seedlings out of the film for field management. Because plastic film mulching can increase ground temperature and improve soil physical and chemical properties, it can advance emergence, advance flowering and fruiting, and prolong the growth period of Trichosanthes kirilowii, which is beneficial for increasing yield.
3. Vine layering propagation. The vines of Trichosanthes kirilowii have the characteristic of growing adventitious roots. In the rainy season, the stem nodes of old vines can be pressed into the soil, and after rooting, they can be cut away from the mother plant and planted separately.
3. Weeding and topdressing
Each year in spring, summer, and autumn, cultivate and weed once, remove weeds whenever they appear during the growth period, keep the field free of weeds, and stop after the plants close the rows. Ten days after transplanting Trichosanthes kirilowii, spray once with a mixed dilute solution of 10-20 ppm gibberellin (GAC) and 0.1-0.3% urea to promote rapid seedling growth; when the seedlings are about 1.5 m tall, apply urea once more; and apply compound fertilizer once each in May, June, and July. Starting from the second year, apply topdressing twice each year: the first time when the seedlings are 30 cm tall, apply 500 kg of decomposed barnyard manure per mu, or 30 kg of cake fertilizer, 10 kg of urea, and 500 kg of soil and miscellaneous manure mixed and composted, then open furrows between the rows and apply, cover with soil and level it, and water; the second time before flowering in mid-June, apply 1000 kg of decomposed barnyard manure per mu, or 50 kg of cake fertilizer, 20 kg of superphosphate, and 500 kg of soil and miscellaneous manure mixed and composted, open furrows and apply, then cover with soil and water.
4. Trellising to support growth
To increase yield, when the stems of Trichosanthes kirilowii are more than 30 cm long, keep 2-3 thick and strong stems per plant for climbing and cut off all other weak vines, and begin to set up a trellis about 1.5 m high. Long 1.8 m pre-made cement strips or bamboo, wood, etc. can be used as main posts, with 1 row of posts for 1 row of Trichosanthes kirilowii, 1 post every 2-2.5 m, and 1 horizontal frame between 2-3 rows. Pull wire on the top, both ends, middle, and four corners of the frame to keep it firm. On top of the frame, arrange two rows of thin bamboo poles or stalks horizontally, and tie them to the wire with rope. Then, insert two small bamboo poles beside each Trichosanthes kirilowii plant, tie the upper ends to the top horizontal pole or wire of the frame, guide the stems onto them, and tie them loosely with fine rope. After Trichosanthes kirilowii grows onto the trellis, promptly remove excessively dense and weak branches, leggy branches, axillary buds, etc., so that the stems are evenly distributed and ventilation and light transmission are good, which can reduce unnecessary consumption of nutrients, reduce the occurrence of pests and diseases, and also facilitate artificial pollination and increase the fruit-setting rate.
5. Artificial pollination
Between the rows of Trichosanthes kirilowii or beside the trellis, configure male plants at a female-to-male ratio of 6:1. During the flowering period, at eight or nine in the morning, use a brush to dip up male pollen and apply it flower by flower to the stigmas of female flowers, so that a large amount of male pollen enters the stigma opening. When the ovary swells to the size of a soybean, the effect of artificial pollination can be checked. Artificial pollination can greatly increase the fruit-setting rate and is an important measure for increasing yield.
6. Pest and disease control
1. Root-knot nematode damages the roots. The fibrous roots first turn brown and rot, and later the roots rot locally or entirely. Diseased plants are short, grow slowly, the leaves fade to yellow, and finally the whole plant dies. When the diseased plant is pulled up, there are many tumor-like bodies of varying sizes on the roots, and white female nematodes can be seen by pricking them open with a needle.
Control methods: (1) In early spring, plow the land deeply and expose the soil to sunlight to kill the source of disease; (2) Before planting tuberous roots, soak them in 800-fold dilution of 4% isofenphos-methyl emulsifiable concentrate for 15 minutes, dry them, and then plant; (3) When preparing the land, mix 10 kg per mu of 5% fosthiazate granules with a small amount of dry sand, spread on the bed surface, turn into the soil, then water, and sow after it penetrates. Alternatively, 1.5 kg per mu of 20% isofenphos-methyl emulsifiable concentrate plus 30 kg of fine soil can be turned into the soil for soil disinfection.
2. Yellow squash beetle. Adults bite and eat leaves, and larvae bite and eat roots, even boring into the roots to cause damage, causing plants to wither and die.
Control methods: (1) Hand-catch in the early morning; (2) Use 1000-fold dilution of 90% trichlorfon to kill adults, and 2000-fold dilution to drench roots to kill larvae.
3. Aphids occur in June- July and damage tender heart leaves and top tender leaves. Control method: spray with 800-1500-fold dilution of 40% dimethoate.