Detailed Explanation of Key Points for Transplanting and Seed Saving of Zhacai (Tuber Mustard)
Zhacai (Brassica juncea var. tumida), a plant of the Cruciferae family, is often covered with simple hairs, forked hairs, stellate hairs or glandular hairs. Flowers are bisexual, usually in racemes; 4 sepals, free, in two whorls; 4 petals, clawed, arranged in a cruciform corolla, a few without petals (such as shepherd's purse, petalless rorippa); 6 stamens, in 2 whorls, the 2 of the outer whorl shorter, the 4 of the inner whorl longer, called tetradynamous stamens; 2 carpels, connate, ovary 1-locular, with parietal placentation, with a false septum in the center, divided into 2 locules, each locule usually with many ovules. The fruit is a silique; those nearly equal in length and width are called silicles, those several times longer than wide are called siliques, such as shepherd's purse and pepperwort being silicles, and Chinese cabbage and radish being siliques. This family has about 350 genera and 3000 species, widely distributed throughout the world. China has 90 genera and 300 species, most numerous in the north and northwest.
The mature stem-tuber mustard before bolting has an aboveground part 60-80cm tall, the underground main root 20-30cm long, and the whole plant generally weighs 2-4kg. The lower part of the aboveground portion is the enlarged tumorous stem, on which grow more than ten large leaves; at the base of the petioles of the large leaves grows the tumorous fleshy stem, with generally 3-5 obvious tumorous protrusions. The epidermis of the tumorous stem is green and smooth, the flesh beneath the skin is white and thick, and the texture is tender and crisp. The tumorous stem portion, namely the green vegetable head, generally weighs about 0.5kg each, with large ones reaching 1-1.5kg. The cooked green vegetable head mixed with seasonings is very tasty; after cooking, its broth has a chicken-soup-like umami flavor. The pickles made from the green vegetable head appear tender, crisp and distinctive.
Zhacai is one type of mustard; the mustard familiar to us ordinary people generally refers to the leaf mustard type, such as nine-head mustard, snow mustard, pig-blood mustard, tofu-skin mustard, etc., but there are also two other types of mustard varieties: one is the type whose modified stem is eaten, namely "zhacai", and the other is the type whose modified buds are eaten, such as the ercai (baby mustard) on the market.
Zhacai is a processed product of stem mustard; its texture is crisp and tender, its flavor is delicious, its nutrition is rich, and it has a special flavor. It is mainly produced in Chongqing and Zhejiang.
Key points for transplanting and seed saving of zhacai
Five key points for transplanting zhacai
First, base fertilizer must be applied deeply: some farmers apply base fertilizer only after raking before transplanting zhacai, so the fertilizer is exposed to the air and is easily lost through sun and rain, greatly reducing the fertilizer use efficiency; therefore, the base fertilizer for zhacai should be applied after plowing and before leveling the land.
Second, one day before lifting the zhacai seedlings, carry out a general pest and disease control in the seedling bed to ensure the seedlings are healthy when moved into the field.
Third, moisten the seedling soil before lifting the seedlings: in this way, fewer roots will be damaged when pulling the zhacai seedlings, improving the survival rate after transplanting.
Fourth, the density should be reduced: according to surveys by agricultural technicians, most farmers transplant zhacai at too high a density; the most suitable planting density for zhacai is 20,000-22,000 plants, that is, a plant spacing of 12cm and a row spacing of 25cm.
Fifth, apply root-setting fertilizer immediately after transplanting: for zhacai seedlings transplanted on the same day, root-setting fertilizer must be applied immediately to ensure full and strong stands after transplanting.
To ensure the fine seed characteristics of improved zhacai varieties, the following four aspects should be noted when saving seeds.
Remove inferior and off-type plants
In the seed-saving plot, keep only plants with good vegetable-head shape, possessing the characteristics of the variety, growing vigorously, free of pests and diseases, and bolting uniformly. All off-type and inferior plants that do not meet this standard must be removed.
Carry out pinching
10--15 days after flowering, remove the tips of the main inflorescence and all branch inflorescences, no longer letting them continue to flower, so that nutrients are concentrated in supplying the remaining siliques, ensuring good silique development and large, heavy seeds. Pinching of seed plants is an economical and effective measure to increase yield.
Prevent insects and diseases
To control insect pests mainly consisting of aphids (also controlling viral disease), imidacloprid can be used at 15 grams per mu, diluted with water and sprayed for control.
Harvest at the right time
When the siliques on the middle and lower parts of the plant turn yellow and the seeds are brown, they can be harvested with branches, tied into bundles, placed in a cool, ventilated place, and threshed after drying in the shade. After threshing, cover the seeds with paper or cloth to dry them in the sun; they should not be exposed bare under the scorching sun.