CATDOLL : CATDOLL: Why can't triploids reproduce?

1. Why can't triploids reproduce?

Because triploid plants cannot synapse normally during meiosis. Since it has three pairs of chromosomes, one of them cannot find a "partner" and synapsis is unsuccessful, so no gametes can be produced. How can there be a baby without gametes?

2. Which fish are best suited for breeding at low temperatures?

There are 14 species of cold-water fish in my country. There are three main sources of cold-water fish: one is to cultivate high-quality rainbow trout varieties through biotechnology and introduction, such as triploid rainbow trout, all-female rainbow trout, Dow's rainbow trout, steelhead trout, golden trout, etc. The second is to introduce new foreign cold-water species: such as Atlantic salmon, silver salmon, white-spotted trout, mountain trout, etc. The third is to develop the breeding of indigenous cold-water fish species in my country, such as red trout, fine-scaled fish, Taimen, etc. The breeding environment conditions are high-density intensive breeding methods. Cold-water fish are grazing fish and are very suitable for high-density flow-through breeding. A large number of edible fish can be raised in limited water bodies, which is unmatched by other fish. The general stocking density in ponds is 800 to 1,500 kilograms per mu, and high-density flow-water aquaculture stocks 20 to 30 fish per square meter. The stocking density of high-density flow-water is dozens of times higher than that of fish farming in other ponds. The yield per mu of high-density flow-water aquaculture is more than 5,000 kilograms. Therefore, high-density flow-water aquaculture occupies less space and has high yield per unit area. It can make full use of fish ponds and water, improve production efficiency and reduce production costs.

3. Why do triploid breeding use tetraploid as the female parent?

If the diploid plant is used as the female parent and the tetraploid plant is used as the male parent in the first year, triploid seeds will be formed. However, the seeds produced by the diploid pollen stimulation in the second year will have no embryos, but the skin will be thick and hard, which cannot achieve the purpose of being seedless.

Polyploidy has two characteristics: slow growth and development, and relatively large fruits.

The tetraploid is the female parent and the diploid is the male parent. At this time, the embryo is triploid, and the seed coat is developed by the female parent, which is tetraploid. Therefore, the development time of the embryo is shorter than that of the seed coat. When the embryo is fully developed, the seed coat has not yet fully developed, so the seed coat is thinner, which is conducive to sowing.

On the other hand, if the tetraploid is used as the male parent and the diploid is used as the female parent, the embryo is triploid and the seed coat is diploid. When the seed coat is fully developed, the embryo is not fully developed. When the embryo is finally fully developed, the seed coat has developed too much. At this time, the seed coat is thicker, which is not conducive to germination when sowing. Therefore, only the tetraploid can be used as the female parent and the diploid as the male parent.

4. In order to reproduce a large number of triploid plants in a short period of time, what methods can be used in theory?

Collect somatic cells from existing triploid plants and perform asexual reproduction (vegetative reproduction) through plant tissue culture.