Apple is also a high-yield fruit tree with strong adaptability to soil. General hills, beaches and mild saline-alkali land can be planted in pieces after appropriate improvement.

Growth and fruiting habits and their requirements for environmental conditions

1. Growth and fruiting habits Apple roots have no natural dormancy period, and adult trees have two or three growth peaks a year, which are transferred according to the distribution of photosynthetic products, the formation rate of aboveground organs and the external environment such as soil temperature and moisture. The first root grows before germination, and turns to low tide when flowering and new shoots grow vigorously. When the new shoots stopped growing, the second root growth peak appeared, which was large in number but short in growth time The third growth peak is in autumn and before and after fruit harvest. Because of the long autumn, long root growth time and large growth in Huaibei area, it is a good opportunity for trees to accumulate and store nutrients. In addition, under the influence of soil temperature, the upper and lower roots grow alternately.

Apple branches can be divided into growing branches and fruiting branches. According to its length, there are several kinds of growing branches: long branches, middle branches, short branches and leafy branches. Sooner or later, different types of branches will stop growing and have different abilities to store nutrients. Leaves and short branches usually stop growing 3-4 weeks after budding and spreading leaves, and the nutrients accumulate earlier, so they are rarely transported to the outside. The middle and long branches stop growing late and sometimes cannot form neck buds. They produce more assimilated nutrients, have greater external transport capacity, and are the main source of nutrients stored by trees (including roots). Therefore, the same tree should have different numbers and proportions of long, medium and short branches, and the new shoots of apples often show obvious secondary growth characteristics. Long branches can be divided into two parts: spring shoots and autumn shoots. Compared with the northern apple producing areas, the growth of new shoots and the proportion of autumn shoots are two characteristics of apple branch growth in Huaibei area. Small trees tend to flourish.

There are differences in germination rate, branching ability and apical dominance among different apple varieties, which affect the differences in dryness, stratification and tree shape of the whole crown, and also affect the early or late fruiting period.

According to their length and flower bud location, fruiting branches can be divided into four types: long fruit branches (> 15cm), medium fruit branches (5cm ~ 15cm), short fruit branches (< 5cm) and axillary flower bud branches. Flower buds are mixed buds, which can produce new buds and blossom and bear fruit at the top after opening. Because the new fruiting branch is extremely short, it expands to form a fruit platform after fruiting, so the fruiting branch is actually the fruiting mother branch. Most apple varieties are mainly short fruit branches, and some varieties occupy a certain proportion of long, middle and axillary flower buds in the young tree stage and the first fruit stage, which is the performance of young trees bearing fruit early. With the growth of tree age, the proportion of all kinds of fruit branches will change and gradually transition to short fruit branches.

Results the fruiting branches of l ~ 2 generally appeared in the new stage, either long or short, which was related to the variety characteristics. The ability of fruit-setting technology to continuously form flower buds varies with varieties and nutrition. Guoguang lasts for 5 years, and Jinguan lasts for about 3 years. Most red stars form buds every other year.

Apple is usually a cross-pollinated tree species, and pollinated varieties need to be configured in production to meet the requirements of normal seed setting rate. However, some varieties such as Guoguang, Anna and Maiyan have a certain degree of self-pollination and seed setting rate. The flowering period is generally 6-8 days. The flowering period is shortened when the temperature is high and dry, and prolonged when the air is cold and humid. Some varieties have a long flowering period, and the flowers are open in batches. The first batch of flowers has good quality and high fruit setting rate, and the flowers can be thinned as soon as possible when the flowers are large in the later period; If the amount of flowers is insufficient, or the first flowers suffer from frost, you can make full use of the later flowers.

In the process of fruit development, there are two processes of falling flowers and fruits. Fallen flowers are the flowers that are pollinated and fertilized, and the ovary does not expand. The first fruit drop occurred at 1 ~ 2 weeks after flowering, which was caused by incomplete fertilization and the young fruit had a certain size. The second fruit drop occurred 2 ~ 4 weeks after the first fruit drop, also known as "fruit drop in June", which was mainly caused by the competition of various organs for nutrients and had a great relationship with the strength of the tree. In addition, some varieties will have a pre-harvest fruit drop before the fruit matures. Fruit dropping in June is a self-thinning phenomenon formed during the development of fruit tree system. Normal and a certain amount of fruit drop is natural, but serious fruit drop caused by bad weather or improper cultivation techniques will affect the yield. It is estimated that only 5% ~ 15% of the flowers can bear fruit in the case of large flowers, which can ensure high yield. Different apple varieties often have different natural fruit numbers per inflorescence. There are many golden crowns and Guoguang, which can reach 4 ~ 5, marshal and red star talents 1, ruby talents 1 ~ 2.

2. Requirements for environmental conditions Apple likes cold, dry and sunny climate conditions. Generally speaking, the average temperature from April to1October is 12 ~ 18, which is most suitable for the growth of apples. When the temperature is too high in summer, when the average temperature is above 26 degrees, the flower bud differentiation is poor, the fruit develops quickly and cannot be stored. The suitable coloring temperature of red varieties before maturity is 10 ~ 20 degrees. If the temperature difference between day and night is small and the temperature is high at night, it is difficult to paint. Compared with the climatic conditions in the northern region, especially the medium-ripe red-mentioned varieties, there is a certain gap from the optimal requirements in temperature, and the gap from the south to the Yangtze River basin is increasing.

The annual precipitation in the main apple producing areas in the world is about 500 mm ~ 800 mm, and dry air and sufficient sunshine are needed for flower bud differentiation and fruit ripening, so the fruit surface is smooth, colorful and full of flower buds. If there is too much rainfall and insufficient sunshine, it will easily lead to too many branches and leaves, poor flower bud differentiation, low and unstable yield, serious pests and diseases and poor fruit quality. The annual precipitation in Huaibei area is about 800 mm, but it is unevenly distributed, and sometimes there is spring drought, summer drought or autumn drought. Rainfall is too concentrated in most years from July to August, so it is necessary to strengthen irrigation and drainage measures.

Apple is a tree species that avoids light. Adequate illumination is beneficial to the normal growth and fruiting of fruits, and also to improving the quality of fruits. Different varieties have different requirements for light. The annual sunshine hours in Huaibei area are more than 2000 hours, which can basically meet the needs of apple growth and development.

In terms of soil, apples are suitable for sandy loam with deep soil layer, good drainage and rich organic matter. The PH value of soil should be slightly acidic to neutral. When the soil is poorly ventilated, the growth of roots is hindered. When the pH is above 7.8, it is easy to be undernourished and lose its green color. The salt tolerance of soil is lower than 0. 15%.