Traditional breeding methods

Traditional breeding technology: paying more attention to the research and utilization of heterosis

Modern breeding technology: biotechnology will embody the concept of special advantage breeding goal in garden plant breeding: the goal that plants will achieve after genetic improvement.

Breeding objectives of garden plants: refers to the requirements for new varieties of garden plants, that is, what excellent characteristics should the varieties have under certain natural, cultivated and economic conditions? 1, characteristics of garden plant breeding objectives.

Diversity (plant types, species; Breeding objectives); High quality is a more prominent target trait of garden plants; Prolonging the supply period is an important factor in the breeding goal of garden plants; Attach importance to the cultivation of dual-purpose garden plants. 2. The main goal of garden plant breeding is (1) good quality, flower type, color, leaf shape, plant type, fragrance and stain. (2) Strong ability to resist pests and diseases and adversity (cold tolerance, drought tolerance, waterlogging tolerance and saline-alkali tolerance)

(3) Prolonging the flowering period, changing the flowering period, and prolonging the flowering period (single flower: cut flower; Whole plant: ornamental flowers and trees) (4) Suitable for cut flowers and storage and transportation.

(5) Low energy consumption (resistance to low temperature, low illumination, high temperature and high humidity, etc.). )

(6) Other objectives (less pollution, high yield, large flowers, easy reproduction, ornamental and economic use). The principle of making breeding objectives is to meet the objective needs of production and people's lives, and the current needs should be combined with long-term development. The combination of the main goal and the general goal requires the combination of possibilities.

4, ways and means to achieve the goal of breeding three,

1, selective breeding: referred to as selection, refers to the genetic variation of the existing plant breeding population, through selection. The breeding method obtains new varieties that meet the breeding objectives through purification and comparative identification. 2. The significance of selection and seed selection (1) Selection is one of the basic ways of plant evolution and breeding. There are two ways of biological evolution: heredity, mutation and selection: natural (survival of the fittest) and artificial (directional selection). (2) The selection of organisms with active creative function is characterized by continuous variation. Selecting the superior and eliminating the inferior can eliminate the interference of inferior plants to superior plants; Directional multi-generation selection has the functions of accumulating variation and strengthening variation, and can obtain variation types that were not found in the population at the beginning of selection.

(3) Seed selection is the earliest variety improvement method applied by human beings, which has made important contributions to enriching the world garden plants. (4) Selection is not only the central link of seed selection, but also an indispensable and important means in all breeding approaches and improved seed selection, which runs through the clock of breeding work and the whole life cycle of breeding objects. (3) The principle of genetic balance of selection: In an infinitely random mating population, if there is no mutation, there will be no selection in any form, and there will be no.

Gene frequency is the percentage of a gene in all alleles of this gene locus in a population. 4. Variation of plant characters.

Gene recombination is the main source of genetic variation among seedlings, which can produce two effects: additive effect; Non-additive effect (interaction effect) mutation: gene mutation and chromosome number and structure variation

Decorative variation: Expressive variation caused by environmental conditions belongs to non-genetic variation. 5. The genetic nature of selection leads to different reproductive rate and survival rate, so that the genetic composition of the population can be changed directionally. 6. Principles for formulating selection criteria (1) Selection criteria should be formulated according to primary and secondary target traits. 2. The target characteristics and standards should be clear and specific. 3. The selection criteria of each feature should be appropriate. 4.

1. Seed selection: Method 2: Select excellent variation types from the seedling population formed after sowing seeds produced by natural pollination, and then cultivate new varieties. Method:

(1) mixed selection method: according to the ornamental characteristics and economic characters of plants, select excellent plants that meet the requirements from the original population, mix and keep seeds, sow the next generation in the mixed selection area, and compare and identify the adjacent cultivation control varieties with the original population plot.

One-time mixed selection method: when the selected population performs better than the original population or the control variety, enter the variety comparison preparation test.