Seed Selection and Saving Methods for Bitter Melon and Key Field Management Points
Bitter melon, also known as bitter gourd, is a plant in the Cucurbitaceae family and an annual climbing herb. The stems, branches, petioles and pedicels are covered with soft hairs, and tendrils grow from the leaf axils. The leaves reach 3 to 12 cm in diameter, with 5 to 7 palmate deep lobes; the lobes are elliptical with serrated outer edges. It flowers at the turn of spring and summer, is monoecious, and the flowers are yellow. The fruit is oblong and has many irregular wart-like protrusions on the surface. The seeds are hidden inside the fleshy fruit, and when mature they are wrapped in a red aril. Bitter melon is a vegetable people enjoy, and although its place of origin is unclear, it is generally believed to be native to tropical regions. It is widely cultivated in South Asia, Southeast Asia, China, and the Caribbean islands.
Morphological characteristics of bitter melon
An annual climbing, weak herb, much branched; stems and branches covered with soft hairs. Tendrils slender, up to 20 cm long, slightly pubescent, unbranched. Petiole slender, initially covered with white soft hairs, later becoming nearly hairless, 4-6 cm long; leaf blade ovate-reniform or nearly circular in outline, membranous, both length and width 4-12 cm, green above, light green beneath, densely and conspicuously pubescent on the veins, sparsely hairy elsewhere, 5-7 deep lobes, lobes ovate-oblong, margins coarsely toothed or with irregular small lobes, apex mostly obtuse-rounded, rarely acute, base with a semicircular sinus, veins palmate.
Monoecious. Male flowers: solitary in leaf axils, pedicel slender, slightly pubescent, 3-7 cm long, with 1 bract at the middle or lower part; bract green, reniform or circular, entire, slightly ciliate, sparsely pubescent on both surfaces, both length and width 5-15 mm; calyx lobes ovate-lanceolate, covered with white soft hairs, 4-6 mm long, 2-3 mm wide, acute; corolla yellow, lobes obovate, apex obtuse, acute or slightly concave, 1.5-2 cm long, 0.8-1.2 cm wide, pubescent; stamens 3, free, anther cells curved twice. Female flowers: solitary, pedicel slightly pubescent, 10-12 cm long, usually with 1 bract at the base; ovary fusiform, densely covered with wart-like protrusions, stigma 3, swollen, 2-lobed. Fruit fusiform or cylindrical, with many warty wrinkles, 10-20 cm long, orange-yellow when mature, splitting from the apex into 3 valves. Seeds numerous, oblong, with a red aril, with 3 small teeth at each end, sculptured on both surfaces, 1.5-2 cm long, 1-1.5 cm wide. Flowering and fruiting period May-October.
Bitter melon is one of the high-quality vegetables people like to eat in summer and autumn. Doing a good job of selecting and saving bitter melon seeds is an important part of achieving a bumper harvest the following year. The methods for selecting and saving bitter melon seeds are introduced below:
Isolation to prevent mixing. Bitter melon is a cross-pollinated crop, and other bitter melon varieties can only be planted at least 2 km away from the seed-production field. Otherwise, different varieties are likely to cross naturally through pollen, making the saved seed mixed and impure.
Artificial supplementary pollination. During the flowering period of bitter melon, rainy weather is unfavorable for cross-pollination, so artificial supplementary pollination is needed to increase seed yield.
Save seed during the vigorous fruiting period. Seed saving in bitter melon should be carried out together with harvesting fruit for market. After the first 2 to 3 harvests, the plants begin to enter the vigorous fruiting period, and seed saving can begin.
Choose good seed plants. Plants that grow vigorously, have no pests or diseases, bear many fruits, have well-formed fruits, and show the characteristics of the variety should be selected as seed plants.
Select seed fruits. Choose the 2 to 3 fruits near the base as seed fruits. Remove the remaining young tender fruits as early as possible so that nutrients are concentrated on growing the seed fruits.
Harvest at the right time. When the seed fruits are fully mature but have not yet turned yellow, they should be harvested. Cut about 5 to 7 cm deep at the stem end of the fruit with a knife, take out the seeds inside, and the fruit can still be sold on the market. At this time the flesh has turned bright red, which is a sign of maturity.
Washing seeds and storage. After the bitter melon seeds are taken out, they should immediately be washed with clean water to remove the seed pulp. Spread the seeds out in the shade to dry, then put them into a loose cloth bag and store them in a ventilated, dry place. The seeds can also be placed in a glass jar; first put fresh rice husk ash about 3 to 5 cm thick in the glass jar, then put in the seeds, and cover them again with rice husk ash. Then store in a cool, ventilated place.
Field management of bitter melon
Bitter melon roots like moisture and avoid waterlogging. Usually attention should be paid to clearing drainage ditches, and if there is heavy rain, field water should be drained promptly. Water use can be based on soil moisture conditions. Generally, on sunny days with strong sun and high evaporation, water disappears quickly, so watering should be done promptly to ensure the physiological water requirement and avoid drought wilting, which affects plant growth and development and flowering and fruiting. During the high-yield period, sufficient nitrogen, phosphorus, and potassium fertilizers should be added along with watering. A simple way is to broadcast various fertilizers on the surface of the bitter melon field. Fully decomposed farmyard manure can also be used. Pay attention to the principle of “small amounts, applied frequently” when fertilizing. When bitter melon enters the vigorous growth period, fertilization should be sufficient, and in hot, dry seasons it should be watered promptly. It is best to spread wheat straw on the bed surface to retain moisture, and at the same time take care to prevent waterlogging.
1. Weeding: There must be no grass in the open areas of the bitter melon field, on the surrounding ridges, or in the ditches. Glyphosate-type chemicals can be used to kill it.
Plant training: Promptly remove old, yellow, and diseased leaves from the lower part of the trellis, as well as branches hanging down to the lower part that have no fruit. If possible, branches on the upper part with no fruit or female flowers should also be removed. Fruits with pests or diseases should also be removed promptly. All removed leaves, branches, and fruits should be put into bags and transported away for destruction. 2. Promoting flowering: Frequently spray small amounts of agents such as “Kaihuajing”, “Cuguoling”, “Penshibao”, “amino acids”, brassinolide, borax, monopotassium phosphate, and calcium nitrate. 3. Harvesting Bitter melon should be harvested promptly, when the young fruit has fully grown. Harvest when the wart-like protrusions on the fruit skin protrude and expand, and the top of the fruit begins to shine. 4. Pest and disease prevention Bitter melon commonly suffers from nematode disease, fusarium wilt (grafted seedlings generally do not develop the disease), powdery mildew, phytophthora blight, anthracnose, and others. The main insect pests are melon fruit fly and aphids. Powdery mildew: It occurs during the flowering and fruiting period, covering the leaves with white powdery material, causing the leaves to lose greenness and turn yellow, resulting in premature plant decline. Control method: When white powdery material appears on the leaves, spray the leaf surface once every 7-10 days with an aqueous solution of cyproconazole, an aqueous solution of triadimefon, Collis, or an aqueous solution of sulfur suspension concentrate for control, spraying continuously 2-3 times, and note that the amount of spray liquid must be large.
Phytophthora blight: On leaves it mostly starts from the leaf tip or leaf margin; the lesions are irregular in shape with indistinct edges, initially dark green and water-soaked, later turning brown. The lesions can expand to cover the entire leaf or more than half of it, and when humid, a ring of white mold grows at the junction of the lesions. Control agents: chlorothalonil, Yike, Bordeaux mixture, vinclozolin, Anke, dimethomorph, phosphorous acid, Ridomil, or Jinlei Duomier by spraying, and remove diseased leaves and take them away for destruction.
Stem borers: Spray and kill with triazophos, monosultap, bisultap, fipronil, chlorpyrifos, or Bt. Aphids: Spray and kill with imidacloprid, acetamiprid, or abamectin. Melon fruit fly: The larvae bore into young fruits and damage them, causing the young fruits to become deformed and change color early, after which they rot and deteriorate and also give off a foul odor. Control method: During the young fruit stage, spray the young fruits 2-3 times with an aqueous solution of fipronil, an aqueous solution of Nongdile, or an aqueous solution of Kung Fu, once every 4-5 days, and promptly remove deformed fruits and burn or deeply bury them outside the garden.