Key Techniques for Propagation and Management of Variegated Clivia
Since the emergence of variegated clivia up to now, appreciation standards have undergone great changes. Initially, any variegated clivia with yellow or white stripes would suffice, but later the appreciation standards for green clivia were gradually incorporated, such as length-to-width ratio, roundness, brightness, springiness, delicate leaf texture, good head shape, good plant shape, ingot-shaped base, good rigidity, etc., which have been fully adopted. Generally speaking, variegated clivia is required to possess not only the colored stripes of variegated clivia but also the appreciation standards of green clivia. The specific requirements are as follows: uniform distribution of colored stripes: alternating white and green, with a certain proportion. Good contrast of colored stripes: distinct green and white, bright and charming, exquisite and translucent, with a three-dimensional feel, transparency, and a refreshing sense. Good stability of colored stripes: for striped clivia, the more uniform the distribution of colored stripes on each leaf and the more similar each leaf is to the others, the better. The colors of variegated clivia roughly fall into five types: edged stripe, mandarin duck stripe, colored stripe, and golden silk stripe, with strains such as Chinese orchid variegated clivia, Japanese variegated clivia, horizontal-leaf variegated clivia, and sparrow-leaf variegated clivia. When breeding, the color requirements and variety characteristics must be considered, and parents must be carefully selected.
I. Breeding
1. Selection of parents
Since the emergence of variegated clivia in the 1980s up to now, the hybridization seedling emergence rate is 15%-20%. Only when plants with fairly uniform colored stripes are selected as the female parent can the seedling emergence rate possibly reach 70%. Therefore, when selecting parents, the traits of both the male and female parents must be comprehensively considered to achieve trait complementarity, so that excellent clivia seedlings can be obtained.
2. Selection of the female parent
According to predecessors' experience, when selecting the female parent, first choose silk-stripe clivia with very transparent silk stripes, where the front and back silk stripes can shine through, and require uniform distribution of colored stripes and high color purity; the greater the contrast between porcelain white and dark green, the better. Next, consider other traits, such as leaf length, width, length-to-width ratio, leaf veins, head shape, base shape, brightness, thickness, rigidity, and other conditions. Under the premise of ensuring the seedling emergence rate of the progeny and a relatively high proportion of variegated clivia in the progeny, the more other conditions conform to clivia standards, the better.
3. Selection of the male parent
When selecting the male parent, first choose relatively transparent silk-stripe clivia. Next, consider compensating for, improving, and enhancing the defects in the female parent's traits. In production practice, it will be found that some male parents are of very good quality, but when pollinated onto different female parent clivia, the progeny obtained differ. Therefore, the selection of excellent male parents requires long-term practice, recording, observation, and summarization before it can be determined.
II. Hybridization Techniques
Clivia is not self-fertile and requires artificial pollination. After selecting the male and female parents, only by implementing correct pollination operation techniques can a large number of fruits be obtained.
1. Preparation before pollination
Before pollination, prepare the necessary pollination tools: toothpicks, brushes, glass dishes, tweezers, labels, pencils or ballpoint pens, etc. When many flowers are blooming, prepare more pollination tools, and be sure to use one set of pollination tools for one male parent.
2. Determining the best pollination time
When the perianth of the female parent's florets cracks open for 2-3 d, the stigma of the pistil begins to secrete mucus and the pistil matures, which is the best pollination period. The best pollination time in a day is from 9:00 to 10:00 in the morning or from 13:00 to 14:00 in the afternoon each day.
3. Collecting pollen in time
When the stamens of the male parent emerge from the perianth, the anthers crack, and the pollen begins to disperse, remove the stamens of the male parent with tweezers, flick the yellow pollen into a glass dish, cover it with a lid, and set it aside for use. Pollen collection must not be too late, as pollen is easily lost if collected too late.
4. Pollination operation
When the petals of the female parent's florets are about to unfold or are at the large bud stage, manually unfold the floret petals, remove the stamens that have not yet shed pollen one by one with tweezers, and then observe carefully. After 2-3 d, the stigma begins to secrete mucus, indicating that the pistil has matured and pollination can be carried out. When pollinating, dip a brush, toothpick, or other tool in pollen grains and gently flick it onto the stigma of the female parent's pistil, until the pollen grains adhere to the stigma. A direct pollination method can also be used. The method is to remove with tweezers the stamens that can shed pollen, directly gently rub the male parent's anther on the stigma, and once the stigma has adhered to yellow pollen grains, the pollination operation is complete. To ensure successful pollination, pollination can be carried out once more the next morning or in the afternoon. Note that the same male parent's pollen must be used for both pollinations. One set of pollination tools should only be used to pollinate with the pollen of one male parent; if it is truly necessary, the previous male parent's pollen grains must be completely killed before use. When pollinating, do not wait until all the florets have opened; pollinate the florets blooming at different stages in batches and in a timely manner to ensure successful pollination. The pollinated florets should be labeled, indicating the pollination time, number of times, name of the male parent, and operator.
After pollination is completed, observe carefully and remove the clivia florets in time; do not wait for them to fall off naturally, so as to avoid consuming nutrients. Under normal circumstances, after the pollination operation is completed, the ovary begins to swell obviously, indicating that pollination has succeeded.
After the fruit has set firmly, if the soil was not changed the previous year, change the soil in time. After changing the soil, immediately pour in 800-times carbendazim solution to prevent root rot, and supply water in time to prevent fruit drop. Then move into the normal female parent management stage.
5. Seed collection
In winter, after about 8 months of growth and development, some seeds of the clivia fruit begin to show color, indicating that the fruit is mature, and seeds should be collected in time. When collecting seeds, cut off the entire flower scape at the middle-lower part with a knife and hang it in a cool, ventilated place. After 10-15 d of after-ripening, extract the seeds from the fruit, wash them clean with water, air-dry them, store them, or sow them immediately. While extracting the seeds, carry out grain selection, discarding poorly developed, holeless, and excessively small seeds.
After the seeds are harvested, make simple records, such as number, harvest date, seed name, names of male and female parents, flower color, plant shape, and adaptability, etc. Mark them with labels, place them in bags, and use them as the basis for subsequent seed treatment, storage, exchange, and sowing and seedling raising. Then store the seeds in a low-temperature, dry, sealed environment to maintain the seeds' germination capacity and wait for sowing.