How to judge the phenological period of sunshine rose grapes?
Each stage of the grape annual growth cycle is associated with the seasonal climate, and the period in which the annual growth phase of the grapes corresponds to the seasonal climate is called the phenological period. Phenological phenomena can be used as indicators of the influence of environmental factors, and can also be used to evaluate the overall effect of environmental factors on plants. Therefore, the phenological period of grapes can guide agricultural operations in agricultural production and provide a certain basis for grape biological observation. Generally, we divide the phenological period of grapes into 8 stages, namely the traumatic flow period, the budding stage, the new shoot growth period, the flowering and fruit setting period, the berry growth period, the fruit ripening period, the post-harvest to the leaf fall stage, and the dormant period.
1. Traumatic period
From spring sap flow to budding. When the soil temperature at the root distribution reaches 6-9 degrees Celsius in early spring, the root system begins to actively absorb water, the sap begins to flow, and a lot of transparent sap flows out of new cuts and wounds of vines, a phenomenon called wound flow (Figure 1). The time and amount of injury flow is related to the variety, soil moisture and other factors, soil moisture is large, and there are many tree injuries: the soil is dry, and the tree injury flow is less or does not occur. The length of the entire trauma flow period is related to the climatic conditions of the year, generally ranging from a few days to half a month, until the winter buds germinate and the injury flow stops.
Figure 1 Wound flow
Second, the embryonic stage
When the temperature rises to 10 degrees Celsius, the winter bud bud swells, stretches out the scales (Figures 2-3), revealing pompom-like buds (Figures 2-4), and then the buds bloom to reveal green (Figures 2-5).
Fig. 2 Winter bud buds swell and stretch out the scales
Figure 3 Pom-pom-shaped buds
Figure 4 Dew green
Third, the new growth period
After germination, the new shoots grow rapidly and unfold their leaves. The nutrient supply of new shoots in the early stage of growth mainly comes from the accumulation of nutrients in the previous year, and the strength of the growth potential is also affected by the degree of nutrient accumulation. Under the condition of sufficient nutrient accumulation and full bud eyes, the growth rate of new shoots is faster. After the leaves reach a certain size and are fully developed, the growth of new shoots depends on the nutrients produced by the photosynthesis of the leaves. When the tree is undernourished or the external environment is harsh, it will cause the inflorescence protosomes to develop poorly and even cause inflorescence degradation (Fig. 5-Fig. 10).
Figure 5 3~4 leaf stage
Figure 6 5 and 6 leaf stages
Fig. 7 7 and 8 leaf stages
Figure 8 Early stage of inflorescence separation
Fig. 9 Middle phase of inflorescence separation
Fig. 10 Inflorescence separation date
Fourth, the flowering and fruit setting period
About 40 days after the grapes germinate, the average daily temperature reaches 20 degrees Celsius, and the flowering period begins. The flowering period of the grapes can be divided into the first flowering period (first flowering period) (Figure 11), the peak flowering period (Figure 12) and the falling period (the end flowering period) (Figure 13). The first flowering period refers to the opening of about 5% of the flowers; The peak flowering period refers to the opening of 60% to 70% of the flowers; Flowering refers to the beginning of flowering, and only about 5% of the flowers are yet to open. On the same fruiting branch, flowering starts from the inflorescence at the base and opens upwards in turn; On the same inflorescence, the middle flower opens first, followed by the basal branch flower, and finally the top flower. This is an important period for determining the yield of the grapes. The temperature required for flowering is above 15 degrees Celsius, and 20-25 degrees Celsius is better, when the temperature is 27-32 degrees Celsius, the pollen germination rate is the highest, and the pollen does not germinate below 15 degrees Celsius. If the flowering period is rainy, it will affect pollination and fertilization, and excessive drought is not conducive to the germination and fertilization of pollen, which can lead to serious flower and fruit drop.
Figure 11 Initial flowering period
Figure 12 Full bloom
Figure 13 Flowering period
5. Berry growth period
From the ovary it begins to swell until the fruit begins to ripen. The first peak fruit drop occurs about 2-3 days after blooming. When the young fruit develops to 3-4 mm in diameter, part of the fruit often falls off due to nutritional deficiencies and stops developing, which is the second peak of fruit drop. After the fruit grows to a diameter of about 5 mm, it generally no longer sheds and begins to enter the expansion stage. After the sunshine rose grape is treated with fruit preservation, there is generally no fruit drop. When the fruit expands rapidly, it is also the period when the fruit needs the most nutrients, when the elongation growth of new shoots slows down and the thickening growth accelerates, the shoots continue to thicken, and the winter buds begin to differentiate vigorously (Figures 14-16).
Fig. 14 Fruit set
Figure 15 Young fruit stage
Figure 16 Hard core period
6. Fruit ripening
From the beginning of the fruit softening to full ripeness. Signs of the beginning of the ripening period of grapes: the green color of the green varieties turns light, yellow, elastic; The red varieties begin to color and the flesh becomes soft (Figures 17, 18). During this period, the sugar content of the fruit increases sharply, the titratable acid and soluble tannin content decreases, the seeds change from green to tan, the seed coat hardens, and finally shows the color and flavor characteristic of the variety (Figure 19). The length of berry ripening varies from variety to variety, generally 20-30 days or more. In the berry ripening stage, the new shoots grow slowly, the branches mature faster, the branches gradually lignify from the base upwards, the skin color changes from green to yellow-brown, and the flower bud differentiation is mainly carried out in the middle and upper parts of the new shoots.
Figure 17 The fruit begins to soften
Figure 18 The fruit begins to soften
Figure 19 The fruit is ripe
7. After harvest to the leaf fall period
During this period, the leaves can still continue photosynthesis, the photosynthetic products are transferred to the roots and branches and accumulate, the starch content in the plant tissue increases, the water decreases, the concentration of cell fluid increases, and the new tip tissue is gradually enriched and lignified from bottom to top (Figure 20). As the temperature drops, the base of the petiole forms a delayering and the leaves turn yellow and fall off (Figure 21). The onset of new ripening varies depending on the variety and cultivation practices, with most varieties ripening at the same time as the berries begin to ripen or slightly later. In addition, early application of potassium fertilizer in production will promote the early lignification of new shoots. At the beginning of the ripening of the branches, the elongation growth of most new shoots and secondary shoots stops, and flower bud differentiation no longer takes place, at which time the root system enters the second peak of growth of the year.
Fig. 20 Leaves of grapes after harvest
Fig. 21 The leaves at the base of the new shoot turn yellow and fall off
8. Dormancy period
From leaf fall until the next year before the onset of wounds. As the temperature decreases, the root system ceases to be active and the tree body enters a natural dormant state (Figure 22). The grapes go through a period of low temperatures for a period of time before they germinate properly the following year. Grape dormancy is divided into two stages: natural dormancy (also called physiological dormancy) and forced dormancy. Usually we use fallen leaves as a sign of the beginning of natural dormancy, and the dormancy period ends before the next year's traumatic flow period; Forced sleep is the period of time after natural sleep. After the grapes enter dormancy, they generally need to stay at a low temperature of less than 7.2 degrees Celsius for a certain period of time to break the dormancy and start germination and growth, and the cumulative number of effective low temperature hours during this period is called low temperature cold demand. If the low temperature demand does not meet the requirements, the tree will enter the forced dormant stage, until the temperature is suitable, the plant will begin to germinate and grow.
Figure 22 When the leaves are littered, the tree is about to go dormant