Detailed Explanation of Flowering Period Regulation Techniques for Mango Cultivation
Mangoes in Guangdong generally bloom around February each year. At this time, they often encounter the influence of cold air from the north moving south, with low temperatures, continuous rain, and high air humidity, causing anthers not to split open, stigma damage, and even flower panicle mildew and death, affecting that year's fruiting. According to expert research findings: low temperatures increase the proportion of male flowers in mango; anthers will not split open at low temperatures below 20°C, and generally split open only above 25°C. When mango blooms under low-temperature and rainy conditions, because the anthers do not split open, there is a lack of pollen for pollination and insect activity is affected, hindering pollination, so mango yields are low or even nonexistent; mango pollen grains will not germinate at low temperatures below 15°C, germinate poorly at 15°C-20°C, and germinate well above 25°C. Therefore, under low temperatures during the mango flowering period, even if a small amount of pollen pollinates, it cannot germinate, so pollination and fertilization cannot occur and fruit set is absent or reduced. It can thus be seen that the flowering period of mango trees must be delayed to avoid the influence of low-temperature and rainy weather in winter and increase yield. After many years of expert research, the following flowering period regulation techniques can delay the mango flowering period, avoid the influence of adverse weather, and increase yield.
1. Carry out heavy pruning
Because the heterogeneity of buds on mango branches is very strong, the terminal bud is robust and mostly sprouts strong shoots, the several buds below the terminal bud are next, and the closer to the base of the branch, the less plump the buds are and the longer the time required for sprouting. Therefore, by adopting heavy pruning measures and using buds at the base of branches to sprout new shoots, the occurrence period and growth period of autumn shoots can be delayed, thereby achieving the goal of delaying the mango flowering period.
2. Delay pruning time
The early or late maturation of fruiting mother branches directly affects flower bud differentiation; generally, fruiting mother branches that mature early differentiate flower buds early. Generally, in orchards where pruning is completed before August each year, the second flush matures in October; fruiting mother branches that mature in October generally bloom around February. If the pruning time is postponed by one month, that is, to September, the mango flowering period can be correspondingly postponed.
3. Spray chemicals to control early flowering
From late December of the current year to January of the following year, use the growth regulator daminozide at 1000-2000 mg/kg and spray mango trees 2-3 times continuously, which can effectively delay mango flower bud sprouting and promote flower bud differentiation.
4. Remove early flower panicles
Mango trees generally begin flowering in mid-to-late December. When flower panicles grow to 5-10 cm, leave only 1-2 cm at the base of the flower stalk and remove all the rest (be careful not to damage the branches), then remove in batches thereafter until before the Start of Spring. This forces flower panicles to emerge from the base of the flower panicle or from leaf axils. After one removal, it takes about 1 month for flower panicles to regrow. If removed twice, the flowering period can be delayed by 2 months. For varieties with a high rate of flower panicle regrowth, removal can be repeated 2-3 times. Use the regenerated flower panicles to set fruit.
5. Spray chemicals to promote flower emergence
After the Start of Spring, that is, in February, spray potassium nitrate thoroughly once to promote flowering. Spray 1%-2% potassium nitrate plus 0.3% urea on the leaf surface, spraying until the leaf surface is moist. Observe once 10 days after spraying; if flower panicles are found to emerge unevenly, spray once more.