What are the bad phenomena of grafting vegetables?

Generally speaking, due to the differences in biological characteristics between rootstocks and vegetable scions, the following undesirable phenomena are easy to occur after rootstocks and vegetables are grafted:

(1) Grafting incompatibility mainly shows that after grafting, the joint surface of vegetable scion and rootstock can't be fused together through callus, and grafted seedlings can't survive. Generally speaking, the farther the genetic relationship between rootstocks and vegetable scions is, the more serious the problem is. (2) The poor grafting compatibility is mainly manifested in that after grafting, the joint surface of vegetable scion and rootstock can not be well fused together through callus, and the survival quality of grafted seedlings is poor and the seedlings are easy to die. Or, although the seedlings can be well fused temporarily, at the peak of fruiting, the joint surface of rootstock and scion is easy to separate, which leads to the death of vegetable scion. This problem is mostly related to the distant genetic relationship between rootstock and scion, but sometimes the grafting combination with close genetic relationship between rootstock and scion will lead to the death of vegetable scion due to environmental changes, poor plant nutrition supply and other reasons. (3) Grafting * * * is unstable mainly because after grafting, the junction of vegetable scion and rootstock can be well integrated, and generally performs well at seedling stage. However, when plants enter the fruiting stage or encounter adverse environments such as high temperature and drought, the joint between the rootstock and the scion often separates, and the scion falls off and dies, or the joint between the scion and the rootstock does not separate, but it is dry or necrotic, resulting in the scion's death. This problem is not only affected by the genetic relationship between rootstocks and scions, but also by the differences in biological characteristics between different varieties of the same vegetable. (4) The deterioration of fruit quality mainly shows that after grafting, the shape of vegetable fruit changes, the appearance becomes worse, the surface is uneven, the color becomes lighter or darker or different shades, and the color is not bright; The peel thickens and hardens; The crude fiber in the pulp increases, the meat becomes hard or soft, or hollow, or the pulp tastes bad and the taste becomes worse; The number of seeds increases, or the number of seeds increases, which is not good for eating.

Because the rootstocks used in vegetable grafting are mostly wild plants, and the commodity characters of wild plant fruits are mostly poor, it is very important to test the quality of grafted vegetables before selecting vegetable grafting combinations. (5) The growth difference of grafted vegetables mainly shows that the growth potential of grafted vegetables decreases instead of increasing, or the disease resistance and cold resistance decrease instead of increasing. The main reason is that the growth potential of rootstock itself is weaker than that of scion vegetables, or the resistance to vegetable diseases is not strong, or the cold resistance of rootstock itself is weak. (6) The overgrowth of grafted vegetables mainly shows that after grafting, the growth potential of vegetables is obviously enhanced, and overgrowth occurs. This phenomenon is not only related to the developed root system and the vigorous growth of rootstocks, but also related to improper management of fertilizer and water in the field and untimely and unreasonable plant regulation.