What are the characteristics of traditional farming and traditional farming techniques?

Traditional breeding attaches importance to the utilization and research of heterosis, and gathers all kin

What are the characteristics of traditional farming and traditional farming techniques?

Traditional breeding attaches importance to the utilization and research of heterosis, and gathers all kinds of excellent genes that are beneficial to improving grain yield and quality into a certain variety to obtain higher yield and the ability to resist drought and other disasters. Defects brought by traditional breeding: the transfer of agronomic traits is easily restricted by interspecific reproductive isolation, and the selected crops cannot be genetically improved; It is difficult to operate and select a gene accurately, and it is easily affected by bad gene linkage.

First, the characteristics of traditional farming

What are the characteristics of traditional breeding?

Traditional breeding attaches great importance to the utilization and research of heterosis, and its ultimate goal is to gather all kinds of excellent genes that are conducive to improving grain yield and quality into one variety through different technical means, so that it can obtain higher yield and resist disasters such as drought.

2. Defects caused by traditional breeding.

(1) The transfer of agronomic traits is easily restricted by interspecific reproductive isolation, and the genetic resources of related or distant species cannot be used for genetic improvement of selected crops. Excellent genes between different species are difficult to use.

(2) Gene transfer through sexual hybridization can't accurately operate and select a certain gene, which is easily influenced by bad gene linkage. In order to get rid of the influence of bad gene linkage, it is necessary to detect multi-generation and large-scale genetic segregation population. Therefore, while gaining some excellent resistance, it may affect the fertility of plants.

(3) The success of sexual hybridization gene transfer generally depends on apparent variation or bioassay, and the detection efficiency is easily affected by environmental factors.

(4) The resistance obtained by traditional breeding is easily influenced by varieties and regional environment. That is, new varieties cultivated in the north may not show obvious resistance when planted in the south.

2. What are the traditional farming techniques?

Traditional breeding techniques include cross breeding, polyploid breeding (haploid breeding), mutation breeding (physics), ultraviolet mutation, chemical mutation, and now ion beam breeding.

1, cross breeding

Cross breeding can combine the excellent traits controlled by parents with different traits, and can also accumulate different minor genes controlled by parents with the same trait. Hybridization changes the genetic composition of organisms and does not produce new genes.

2. Polyploid breeding (haploid breeding)

(1) polyploid breeding

(1) Polyploid breeding refers to the use of artificial mutation or natural variation to double the cell genome and obtain polyploid breeding materials, so as to select excellent varieties that meet people's needs.

② After polyploidy, the interaction of multiple alleles produces more combinations and more diverse functional changes, so it has higher heterozygosity and faster environmental adaptability than diploid parents, showing the characteristics of enhanced stress resistance and overcoming distant hybridization sterility, which is favored by horticultural breeders.

(2) Haploid breeding

Haploid breeding adopts plant tissue culture technology (such as in vitro culture of floral medicine, etc.) ) induce haploid plants, and then double the genome by some means (such as colchicine treatment), thus restoring the normal chromosome number of plants. Haploid is a biological individual whose somatic chromosome number is the gamete chromosome number of this species.

3. Mutation breeding

Mutation breeding refers to the breeding method of inducing the genetic characteristics of animals and plants to mutate through physical and chemical factors, and then selecting individual plants/individuals that meet people's certain requirements from the mutated population, and then cultivating new varieties or germplasm. It is a modern breeding technology developed after seed selection and cross breeding.

4. Chemical mutagenesis

The technology of mutating DNA by using chemical mutagens such as base analogues, deamination agents and alkylating agents.

5. Ion beam breeding

Belonging to one of mutation breeding methods. That is, using ion beam as mutation factor, ion beam is injected into seeds, cells or other organs of plants to induce genetic changes in plants, so as to obtain various changes and cultivate new plant varieties through artificial selection.