What Is the Haploid?

Chromosome ploidy refers to the number of homologous chromosomes in a cell, of which only one group is called "haploid" or "haploid". It should be noted that haploid is different from haploid (individuals whose somatic cells contain a chromosome). Some haploid organisms contain more than one chromosome in their somatic cells . Most organisms are diploid, and their haploid somatic cells contain a chromosome. If the original species is polyploid, then its haploid somatic cells must contain a large number of chromosomes. In one. For example, the haploid of the tetraploid rice contains two chromosomes, and the haploid of the hexaploid wheat contains three chromosomes instead of triploids.

English name: Haploid

Concept: the number of somatic chromosome groups is equal to the gamete of this species

Haploid individuals usually consist of

Haploid contains this species

The concept of haploid: There are two kinds of concepts about haploid in the textbook:

(1) Any

After using various effective methods to generate haploids, chromosome artificial or natural doubling is performed to restore normal fertility of plants and quickly obtain stable breeding methods for new varieties. Haploids are individuals, tissues or cells that have only gamete chromosomal components. Plants differentiated and grown from such cells are called haploid plants. Such plants cannot reproduce and must double their chromosomal components in order to continue to reproduce and obtain stable and consistent offspring .

Crop breeding methods for forming pure lines by haploid. Generally, anthers and pollen are used for explants for tissue culture. Plants are produced from microspores via callus or embryoid bodies, or plants with full gamete dyeing (haploid plants) are produced by parthenogenesis, artificial induction, etc. ), Homozygous diploids are produced after chromosome doubling, and then through field breeding tests, excellent new varieties are obtained. Haploid breeds can shorten breeding years and improve breeding results.

Haploid species have succeeded in tobacco for the first time since they were cultivated with pollen from Datura in the 1960s. Since the 1970s, haploid vegetables have been induced by anther culture including cabbage, kale, stone cypress, tomato, eggplant, pepper, sweet pepper, potato, and Chinese cabbage. New varieties or lines of rice, tobacco, wheat, eggplant, sweet pepper and other crops were bred for the first time in China.

The frequency of haploid plants produced by parthenogenesis, parthenogenesis and a gamete reproduction in nature is very low, generally only a few thousandths, and some are below one hundred thousandth. Artificial induction can increase the frequency of haploid occurrence. Tissue culture, including anther culture, pollen culture, ovary culture, and pollen mother cell culture. Haploid-induced plants have been successfully used on hundreds of plants, demonstrating the prospect of haploid species. Among them, anther culture is the most widely used. The anther is mainly inoculated with microspores at the mononuclear stage as the material to inoculate the induction medium. After the microspore cells are differentiated, they divide to form callus or embryoid body. The medium induces rooting to form a complete plant, which is then transplanted into the field. Double treatment can be performed before and after transplantation to obtain homozygous diploid plant offspring.

Haploids include haploid and aneuploid. An important basis for identifying haploid plants is that the number of chromosomes in the root tip cells is the same as the number of gametophytes. Its main botanical characteristics are: plants are weak, leaves, flowers, and stomata are smaller than diploid plants, stigmas are long, pollen grains are small and empty, and they are not strong.

There are four ways to double the chromosomes of haploid plants: Intranuclear doubling, that is, chromosomes increase during mitosis, the number of chromatids in the terminal stage doubles, and then they are paired in mitosis. Mitosis in the nucleus, that is, mitosis lacks a spindle, and the nuclear membrane does not disappear during the entire process. Effective division of the colchicine effect. Nuclear fusion in adjacent cells or binuclear cells . Natural doubling is generally not easy to produce distortion, and artificial mutation has a higher distortion rate ^[2] .