Almonds have the habit of blooming early, blooming earlier than peaches and at the same time as apricots. Almond flower buds expand and open faster than leaf buds, giving the impression that flowers bloom first and then leaves, and the leaf expansion time is in the middle and late stages of flowering. In the main almond-producing areas of Xinjiang, the flowering period of almonds is mainly from late March to early to mid-April. A single flower blooms for 5 to 7 days, and the flowering time of a single plant generally lasts about 10 days. The blooming periods of the main cultivars completely overlap. Since almonds bloom early, they are very susceptible to late frost damage. When building a garden, you can choose to plant late-flowering varieties, and be careful not to choose a garden site in a low-lying area.
Almond has a well-developed root system, especially the lateral root system, which is mainly distributed in the 20~40cm soil layer. The root system is highly drought tolerant. Different rootstock types have different growth and distribution characteristics, stress resistance, and adaptability.
Almond has strong germination ability, vigorous new shoot growth, and the annual growth can reach more than 2m. The buds are precocious and can produce secondary branches in one growing season. Summer pruning can speed up tree reshaping for earlier fruiting. At the same time, topping can be used to control the growth of new shoots, enrich the branches, and improve their overwintering ability. The latent buds of almonds have strong germination ability and the crown can be easily renewed.
Almond is a light-loving tree species. When planted too densely or in shade, the branches tend to become slender and bent, with hollow interiors, elongated branches, and poor fruiting. This should be done when selecting a garden site and determining the spacing between rows. Notice. Almonds mainly produce fruits on middle fruiting branches, short fruiting branches or groups of short fruiting branches over the next year.
The physiological differentiation of almond flower buds is completed around the end of May. Before then, removing branches and leaves and spraying gibberellin can inhibit the formation of flower buds. Strengthening fertilizer and water management and improving the nutritional level of the tree can promote flower bud differentiation.
After the physiological differentiation is completed, it enters the flower bud morphological differentiation stage. The morphological differentiation of almond can be divided into six stages: pre-differentiation stage, early stage of differentiation, calyx differentiation stage, petal differentiation stage, stamen differentiation stage and pistil differentiation stage. The time required for each variety to complete morphological differentiation is 110 to 125 days. The rate of morphological differentiation is slow before the fruit matures and accelerates after the fruit matures.
Most varieties of almonds are self-fertilizing and require higher temperatures for pollination. The pollination test conducted by Li Jiang showed that the self-pollination fruit setting rate of the main cultivated varieties is extremely low, while the varieties have a good affinity for mutual pollination (see Table 1). Therefore, it is necessary to configure pollination varieties with the same flowering period and have enough bees to ensure pollination during the flowering period to obtain good yields.
Almond fruits mature 3 to 4 months after flowering. In the first stage of fruit development (40 days), it can reach 95% of the length of the mature fruit (i.e., longitudinal growth). In the second stage (40 days), the length of the fruit increases by only 5%, and it enters the hard core stage 72 to 80 days after flowering. At 83 to 90 days after flowering, the expansion and growth of the embryo and cotyledons ends. The increase in kernel weight occurs from the beginning of hardening of the kernel to the cracking of the peel, which is the maturity stage. The moisture content of almond leaves decreases from 82.1% to 25% during the ripening process, and the rate of fat accumulation in the fruit is fastest in the month before the fruit matures (June to July).
Almonds start to bear fruit earlier. Generally, seedlings start to bear fruit in 3 to 4 years. Grafted seedlings start to bear fruit in 2 to 3 years. They enter the fruiting period in 12 to 15 years. After 40 to 50 years, the fruiting power begins to decline. . The life span of almonds is 120 to 130 years, and it can live longer under good cultivation and management conditions.
Table Fruit setting rate of different almond varieties in pollination test