The method of cultivating grafted rootstock seedlings of mango

There is only one seedling per seed of mango mono-embryo variety, while multi-embryo variety can germinate and grow into multiple seedlings. The single embryo seed has only one embryo (sexual embryo), the embryo is large, and the single seedling developed is strong; the polyembryonic seed has multiple embryos, the embryo is small, and the seedlings developed into multiple plants are weak. Therefore, it was emphasized to use single embryo variety as rootstock in the past. However, the consistency of rootstocks is very important to improve the yield and quality of mango. Single embryo seedlings are sexual seedlings, and their growth performance varies greatly. Great differences in growth and yield of different plants in orchards are likely to be caused by rootstocks. Therefore, the seeds of polyembryonic varieties should be selected to cultivate rootstock seedlings after experiments. In the past, it is recommended to use soil awn with small fruit, less pulp, poor quality but full embryo as rootstock, which is mostly single embryo and strong growth, because of the above reasons, it is not ideal to be used as rootstock. The polyembryonic varieties suitable for rootstocks need to be determined by the tests of grafting affinity, adaptability, high quality and high yield.

Seedlings are mainly used as rootstocks or breeding experiments. The seeds used to cultivate seedlings should come from the same variety, collected from mature fruits, and the seeds should be full, disease-free and insect-free. The seeds should be taken out and sown as soon as possible, because the mango embryos are sensitive to water loss, and once dried, the germination power decreases rapidly. The seeds should be peeled off the fibrous skin and membranous layer, soaked in 0.1% potassium permanganate solution for 1 minute, taken out to dry and sowed. It is best to use medium coarse river sand or vermiculite as sowing substrate, and the thickness of sand bed is 30 cm.

If it is a used seedbed, spray it thoroughly with 1% formalin solution, cover it with plastic film for 24 hours, and then let it dry for 24 hours to dissipate the smell. The seed embryo can also be moisturized in the dark to make the germ germinate before sowing. When sowing, the seed embryo is placed flat, while the single embryo makes the germ in the same direction, closely arranged, with a row spacing of 15 cm. After sowing, cover a layer of 2 cm thick river sand or vermiculite. If you do not cover the plastic film to moisturize, when the temperature is high and the air humidity is low, you must sprinkle water every day. If the film is covered with shade and moisturizing, it can be drenched with water once every 5 days to keep it dry. In Guangzhou, the seedlings can be unearthed in 20 days after sowing from June to October. Generally, they are transplanted to the nursery ground when they have 5 red leaves. Each polyembryonic seed can be divided into 4 seedlings, the big and small seedlings should be graded slightly, and the weak seedlings should be eliminated. The transfer time of single embryo seedling can be a little later.

In order to cultivate high-quality seedlings, it is best to use a seedling bag with a length of more than 40cm and a soil of more than 3kg to cultivate rootstock seedlings for grafting. Because mango has few whisker roots, bagged seedlings are conducive to transplanting and survival. For those who raise seedlings in the nursery, choose more clayey soil so that it is easy to bring mud clumps when raising seedlings. When transplanting, it is necessary to cut off part of the main root, leaving about 10 cm, or coil the main root to promote the occurrence of lateral root. The soil quality of the seedling bag can be slightly sandy, but because fertilization is not as convenient as the field, enough mature organic fertilizer should be mixed to ensure the good development of the root system. After moving the seedlings, continue to shade until the leaves are fully transcribed, and then give full light after the branches are ripe. Single embryo seeds can also be sowed directly in the seedling bag.