In order to solve the problems of labor-consuming, time-consuming and high cost of artificial pollination in the breeding of self-incompatible lines, scholars at home and abroad have made a lot of explorations, and put forward treatment methods such as electric pollination, thermal pollination and utilization of CO2, amino acids, vitamins, plant hormones and phenols, but there are still problems such as unsatisfactory improvement of seed setting rate or high cost. The research group of Chinese cabbage breeding in College of Horticulture, Nanjing Agricultural University chose NaCl solution with low cost, simple operation and easy popularization, and achieved obvious results. Pollination with 50g/L NaCl solution for 30min improved the work efficiency by 15 ~ 20 times compared with artificial pollination in bud stage, which was similar to the effect of NaCl on Chinese cabbage and Chinese cabbage. The reason why NaCl solution can overcome the incompatibility of common Chinese cabbage is that both Na+ and Cl- are activators of enzymes, so it can change the recognition protein on the stigma, thus improving the affinity index.
A lot of work has been done in the breeding of self-incompatibility lines in Chinese cabbage, but there is still a lack of research on genetics, morphology, physiology and biochemistry. Shi et al. (200 1) studied the self-incompatibility of common Chinese cabbage by affinity index method and fluorescence microscope observation method, and found that the reaction site of self-incompatibility was on the stigma-after pollination, there was obvious callose reaction on the stigma surface. The results of the above two methods are completely consistent, but the fluorescence microscope observation method is simpler and more accurate, and can be used to detect the self-incompatibility of ordinary Chinese cabbage.