In March, choose a sunny place, make a bed with a spacing of 50 cm, put compost on it, dig a hole with a depth of 30 cm, and put the seed potatoes in it, which is about three times as deep as potatoes. Put fertilizer between potatoes.

(1) Cut it in half and sprinkle a layer of coal ash on the incision.

(2) When planting, the incision is downward.

Small knowledge

Potatoes originated in the Andes of South America and spread to Mexico around 1500. It spread from Mexico to Spain in 1570 and to Britain in 1590.

This period is the period when Europeans extended their territory to Asia and America, and potatoes also spread to various countries with Europeans.

Plants whose nutrients are stored in roots, stems and other parts of the ground are called potatoes. This plant is rich in starch and has been cultivated all over the world since ancient times.

Planting method of potato

① Make seedbeds in February or March, and then plant sweet potatoes as seeds. When the temperature reaches 30-35 degrees Celsius, it will germinate. When the stem grows to 30 cm, it will be cut and planted as a seedling.

② In May or June, make ridges at intervals of 60-90 cm in sunny places, insert branches and put compost on them.

Planting potatoes with no-tillage and full straw mulching in paddy field

1. 1 hybrid breeding

(1) interspecific hybridization

Interspecific hybridization is the most commonly used breeding method in China at present. Generally, it includes four ways: heterozygosity among varieties (lines), self-crossing, backcrossing and heterosis (referring to hybridization between pure inbred lines). Potato variety breeding in China began in the mid-1940s. Over the past 50 years, more than 100 varieties have been bred, most of which were bred by interspecific hybridization, and a few varieties were bred by selfing, such as Kexin 12, Kexin 13 and so on. Backcross method is mainly used to improve parent materials and rarely used to cultivate new varieties. At present, backcross method is mainly used to improve the population of new cultivated varieties. With regard to the utilization of heterosis, as early as the early 1970s, China began to establish research projects, but after more than 20 years of research and exploration, little progress was made, and only some excellent hybrid parents were obtained. This is mainly because the genetic basis of potato is extremely complicated, and it is necessary to self-cross several generations, even 10 generation, in order to obtain homozygous inbred lines. However, after several generations of potato self-crossing, self-compatibility often occurs, and the yield and viability decrease, which leads to the inability of self-crossing. Nevertheless, China's research level in this field is still ahead of the world.

(2) Interspecific hybridization (distant hybridization)

In China, the research on potato distant hybridization began in 1950s. After more than 40 years of active exploration, only some achievements have been made in related cultivated species. Through the improvement of newly cultivated varieties, a group of valuable excellent parents were screened out, and some excellent varieties with different uses were cultivated by using these parents, such as Dongnong 304, Kexin 1 1, Neishu No.7, Hushu No.7 and so on. In the use of wild species, due to technical reasons, there has been a hesitant situation. However, 60% of the varieties bred in Europe, America, the former Soviet Union and other countries are bred by distant hybridization, and they are all related to wild species. Such as Pulsatilla, Catarrhagia and Milla.

Variant 1.2

(1) Radiation mutation breeding generally includes ion beam mutation methods such as ionizing radiation (such as X, γ, Co60), ultraviolet ray, laser, and space radiation breeding developed in recent years. The results of potato breeding by radiation mutation in China are few, and the progress is very slow, which is far less rapid than other crops (such as wheat, rice, soybean, etc.). ). So far, only a few varieties such as Lushu 2 have been bred by radiation, which is limited to Co60 radiation. Others such as ultraviolet radiation, laser radiation, plasma beam and space mutation breeding have not been reported.

⑵ Chemical Mutation Breeding In 1950s, some people artificially treated potato tubers with colchicine, hoping to obtain mutagenic materials, but with little effect. At present, chemical mutagens are mainly used to study chromosome doubling, and there is no report on breeding varieties. ⑶ Bud mutation breeding can be divided into natural bud mutation and artificial bud mutation. As a breeding method, natural bud mutation has never attracted the attention of potato breeders in China. Since the 1940s, Bashang Research Institute of Hebei Province has bred only one variety-Ba Fengshou from Shaza 1 by bud mutation method. And some famous foreign varieties, such as Mapi Bilbank, Red Stripe White, Baron, etc. , are bud mutation reproduction. About artificial bud mutation, China is still blank.

1.3 Biotechnology Breeding

(1) Genetic engineering breeding in China started late, but it developed very rapidly. Breakthrough progress was made in potato breeding;

① The transgenic potato with high essential amino acids entered the field experiment stage in agricultural year, which was an 863 plan project sponsored by researcher Lin of Institute of Botany, Chinese Academy of Sciences;

② Transgenic potato with PVY coat protein gene has also entered the field experiment;

③ Genetic engineering of antimicrobial peptides from potato bacterial wilt has been successful;

④ Transgenic potato with PSTVd resistance obtained by ribozyme genetic engineering has also come out and has been mass-produced. This is the first successful example of using ribozyme to control viroid in the world.

⑤ The transgenic project of potato resistance to late blight has also made a major breakthrough, and now resistant plants have been obtained;

⑥ The introduction of foreign DNA is being tested, and mutant materials have been obtained.

⑵ Chromosome engineering breeding, also known as "ploidy operation" breeding, is a breeding scheme put forward by Chase in 1963, that is, tetraploid is reduced to diploid, breeding, hybridization and selection are carried out at diploid level first, and then chromosome doubling is carried out to restore the hybrid to tetraploid level. This shows a bright application prospect for the utilization of wild species. At present, China has successfully induced diploids and haploids, doubled chromosomes and used 2n gametes to obtain some tetraploid hybrids of "diploid-wild species", which have been applied to breeding.

(3) Cell engineering breeding mainly refers to the method of breeding through anther tissue culture, protoplast culture, somatic cell fusion and hybridization.

① Anther tissue culture: Dai of Gansu Agricultural University reported that some excellent lines with different characters have been selected by using anther tissue culture technology and are currently being applied in breeding.

② Protoplast culture: Only a few units such as Gansu Agricultural University and Jilin Agricultural University carried out this research, and regenerated plants were obtained through protoplast culture.

③ Somatic cell fusion and hybridization: China is in the experimental research stage. At present, only Dai et al. of Gansu Agricultural University reported this research in China, and obtained somatic hybrid plants.