The causes of fruit drop, flower abortion, and abnormal pomegranate flower development can generally be categorized into four types:
(1) The pistil is taller than the stamen;
(2) The pistil and stamen are equal in height;
(3) The pistil is shorter than the stamen, with partial degeneration (about 1/2 to 1/3);
(4) Complete degeneration of the pistil.
The timing of pollen release from the anthers and the availability of pollen on the stigma play a critical role in successful pollination. Environmental factors such as temperature and light intensity significantly influence this process. Adequate sunlight and moderate temperatures are ideal for pollen release. Pomegranate flowers typically open between 8:00 AM and 10:00 AM. Pollen begins to loosen around 8:00 AM on the second day after the flower opens, especially before May 20th. A large amount of pollen is released around 4:00 PM. As temperature and light increase, the pollen loosening occurs more quickly, often on the same day. By 6:00 PM, the pollen is usually scattered, and the next day at 8:00 AM, the flowers begin to loosen again. However, after June 20th, rising temperatures and stronger light reduce the number of anthers, resulting in less pollen and weaker, paler flowers.
The ability of the stigma to receive pollen directly affects the fruit set rate. In natural conditions, pollination that occurs two days before or on the same day as flowering tends to result in higher fruit set. However, if pollination takes place three days after the flower opens, the stigma may have already lost its ability to accept pollen.
Insects play a vital role in pomegranate pollination. Although pomegranate trees have some self-fertility, their fruit set rate is relatively low without cross-pollination. Insects are the primary pollinators, and their activity strongly influences the fruiting success, especially during early flowering. Before May 30th, lower temperatures and fewer pollinating insects are major factors affecting early fruit set.
To improve fruit retention and overall yield, several measures can be taken:
1. Enhancing flower quality is crucial. During the first two stages of flower bud differentiation, increased fertilization and top dressing during the non-flowering period help promote healthy flower buds, increasing the proportion of normal flowers and improving overall flower quality.
2. Creating favorable pollination conditions involves planting multiple varieties when setting up the orchard. At least three different varieties should be included, with a general ratio of 6:4. If bees are available, they should be introduced into the orchard before flowering to assist in pollination. It is important to avoid pesticide use during this time. Artificial pollination can also be used, where pollen from both female and abortive flowers is collected and applied directly to the stigma of mature flowers. This is best done when the pollen is bright yellow and the stigma is fresh, either just before or immediately after the flower opens.
3. Thinning buds and fruits is essential. Once the complete flowers and abortive flowers are identified, about 70% of the abortive buds should be removed by the end of the flowering period. In clustered inflorescences, only one top flower should be left, and the rest should be removed. Similarly, only one fruit per cluster should be retained. This helps concentrate nutrients, improve fruit set, increase fruit weight, and enhance yield and quality.
4. Using growth regulators can further boost fruit set. A handheld sprayer can be used to apply gibberellin (5–10 ml/L) to fully opened flowers, along with 2,4-D sodium salt (5–20 ml/L), sprayed two to three times during the flowering period. These treatments help improve pollination success and ultimately increase the fruiting rate.
Probiotics Capsule
Yogurt Capsules,Probiotics Capsule,Probiotics Supplement,Prebiotic And Probiotic Capsules
Biodep Biotechnology Co. ,Ltd. , https://www.biodep.com