The jointing stage refers to the period when the internodes of cereal crops rapidly extend upward, the heading stage refers to the period when the flag leaves are extended to the heading of cereal crops, and the jointing stage to booting stage refers to the period from the jointing stage to heading and flowering of cereal crops, which is also called the concurrent period of nutrition and reproductive growth. Taking wheat as an example, the life of crops is generally divided into three growth stages. The first stage is vegetative growth, the second stage is simultaneous vegetative growth and reproductive growth, and the third stage is reproductive growth, from heading to maturity.

First, jointing and booting stage

1, jointing stage refers to the period when the internodes of cereal crops extend upward during the growth process. During this period, plants grow rapidly and need a lot of water and nutrients. Generally, the first internode of more than 50% plants in the whole field is exposed to the ground 1.5-2.5cm, and the booting stage refers to the elongation of flag leaves of cereal crops until heading. The jointing to booting stage is the stage from jointing to heading and flowering of cereal crops, which is also called the parallel period of nutrition and reproductive growth.

2. Wheat is the main crop, and its life is divided into three growth stages. The first stage is the vegetative growth stage, from emergence to emergence, generally taking root, growing leaves and tillering. The main purpose of this stage is to cultivate strong seedlings and lay the foundation for strong stalks with multiple ears. The second stage is that vegetative growth and reproductive growth are carried out simultaneously, from the rising stage to the heading stage, including the growth of roots, stems and leaves and the differentiation and development of wheat ears; The third stage is the reproductive growth stage, from heading to maturity, which is generally dominated by grain formation and filling maturity, and the growth of roots, stems and leaves gradually stops.

Second, the rice breeding model

1, rice belongs to sexual reproduction, which is mainly propagated by self-pollination or cross-pollination to form fertilized eggs. After dormancy, rice seeds will absorb nutrients, break out of their shells and form roots and plants under suitable conditions of sunshine, water and climate. Then there will be an ear differentiation stage, and then it will enter the heading and flowering stage. This stage is mainly pollen reproduction and fertilization, and fertilized eggs will mature into seeds.

2. Rice is the main edible crop in daily life, and its cultivation area is relatively extensive in China. Before planting rice, seeds must be treated, which is a prerequisite for rice planting technology. Before planting, clean the selected seeds, then put them into potassium permanganate solution for disinfection, and then put them into gauze bags to accelerate germination, and keep the temperature at 30? C can germinate.

3. In order to achieve high yield of rice, it is necessary to ensure the fertility of cultivation media and combine intertillage weeding treatment with soil preparation. Then, an appropriate amount of organic fertilizer, calcium superphosphate, potassium sulfate and other fertilizers are added to the soil, mixed evenly, and then a small amount of dixone is added for sterilization.