How can artificial pollination of pear trees ensure success?

How can artificial pollination of pear trees ensure success? Pear is a kind of self-pollinated tree species with strong self-fertility. Most pear varieties are self-pollinated and sterile. Although a few pears can self-pollinate, the seed setting rate of a single pear variety is very low. For this reason, pear trees are usually planted by artificial pollination. In the Hongzhiyi area of Salt Lake area, pear farmers collect yellow pear pollen to pollinate crisp pear; in Longju town of Salt Lake area, pear farmers even go to Sichuan in groups to collect pollen to pollinate red crisp pear. In recent years, the demand for artificial pollination has also led to pollen business. In some villages, there are more than ten pollen sellers, and the price gap is not small.
Whether collecting pear pollen for artificial pollination or purchasing commercial pear tree pollen for artificial pollination, there will be two different results: some fruit setting rate is high, some fruit setting rate is not ideal.
Artificial pollination of pear trees
There are many factors affecting fruit setting rate, among which pollen activity can not be ignored.
How much pollen does it need per mu? The pollens of different pear varieties are similar in morphology, mostly elliptic or oval, ranging in size from 30.19 to 44.38 x 27.09 to 42.57 microns. This size is a bit abstract. How to visualize the size and weight of a pollen grain? According to the calculation of the largest pollen grains of pear trees, at least 230 to 300 pollens can be placed in a centimeter of length. The number of pollens per cubic centimeter is about 12 million to 270,000. At present, no one has calculated the proportion of pollen, but you know that the proportion of water is 1. Let's calculate the proportion of pollen by 3 for the time being. The number of pollen per gram is at least 4 million grains. If each pollen is active, it can be pollinated. If 20,000 pears are left per mu and refined pollen per gram, at least 200 mu of pear orchard can be pollinated. In fact, the activity of pollen is far less than this high, and most of the pollen will not fall on the stigma. Therefore, when artificial pollination, the recommended amount of refined pollen is 20 grams, which increases the insurance factor by 4,000 times on the basis of theoretical accounting. That is to say, 20 grams of refined pollen are used per mu, as long as one pollen tube is guaranteed in 4000 pollen grains.
Pollen germination rate test will be carried out by regular manufacturers before pollen leaves the factory. Some people will do similar experiments for the common people when they sell pollen in villages and alleys. But how high is the germination rate of pollen qualified? It is understood that there is no specific standard at present. In 1985, Professor Jin Qiang, Department of Horticulture, Sichuan Agricultural College, published a paper on the flower organ characteristics and pollen viability of pear trees. The paper clarified that the pollen germination rates of Jinhua, Chonghua, Huaxi, Xueshan No. 1 and Zaobai were all above 80%; Zaobu and Chetou were next, and the germination rates were above 60%; Jinchuan, apple pear and Jingbai were again, and the germination rates were above 30%. Mutual pollination of the above varieties will not affect yield. Only varieties with germination rate less than 10% can not be used as pollinating trees. Thus, as long as the germination rate of pollen reaches 30%, the fruit setting requirement can be achieved.
Although the pollen grains are very small and the amount of pollen is very large, the germination rate should be no less than 30%, after all, the higher the activity of pollen, the safer it is. When people collect pollen by themselves, it is best to keep pollen activity to the maximum. This requires you to understand the following knowledge:
1. Pollen viability varies in different developmental stages. Except for Apple pear, pollen viability of other cultivars has been declining, the pollen germination rate of budding flowers in the early flowering stage is mostly below 30%, the pollen germination rate of fully blooming flowers in the full flowering stage reaches the peak of germination, and the pollen germination rate decreases to less than 20% when the flowers wither in the final flowering stage. It can be seen that with the development and maturity of pollen, the viability of pollen gradually increases, and the pollen viability of flowers in full bloom is the strongest. At the end of flowering, the temperature rises, the pollen itself metabolizes vigorously, and the viability decreases quickly, or even loses its viability completely.
2. Pollen collection is the best. The so-called big bell flower, that is, the flower that will open in a day or two, is characterized by the opening of the petals, but not yet fully open. In production, some people pick flowers whose bones or petals are not open. The pollen activity of such flowers is not high.
3. It is best to add a little sucrose to liquid powder spraying. According to Professor Jinqiang's experiment, sucrose concentration has a direct impact on pollen germination. The optimum concentration of sucrose in pollen germination medium is 5%. In this medium, the pollen germinates quickly and the length of pollen tube is not easy to rupture. On 10% sucrose medium, the pollen grains sprouted well, but the pollen tube was very short and easy to rupture; 15% sucrose medium significantly inhibited pollen germination. It can be seen that when the liquid powder is sprayed, the effect of adding half a half sugar to the pollen solution of each 30 jin spray will be better.

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