Diseases

Tissue necrosis — Chinese cabbage

Brassica rapa L. subsp. pekinensis (Lour.) Hanelt

A physiological disorder known as tipburn or internal gray speck, caused by a localized calcium deficiency in the rapidly growing tissues of the head. The disorder leads to the death of leaf areas and often triggers the development of secondary infections.

In the reference 12 varieties crop Napa cabbage, where this is mentioned in the description.

The mechanism of necrosis development is associated with impaired calcium transport to the growing point, triggered by fluctuations in soil moisture, high air humidity, high temperatures, or excessive nitrogen fertilization. Nutritional imbalance, particularly an excess of ammonium forms of nitrogen or potassium, inhibits the uptake of calcium required for maintaining the cell wall structure of Chinese cabbage.

Symptoms are often hidden inside the head, which may appear healthy externally. Upon cutting, black specks or extensive gray-brown dry spots are revealed along the leaf margins, which eventually develop a papery texture. Affected areas often become entry points for secondary bacterial infections.

Resistance to tissue necrosis in Chinese cabbage is polygenic. In breeding, it is determined not by individual genes but through quantitative expert assessment of variety susceptibility to tipburn. Currently, scientists are working on identifying QTLs related to calcium metabolism and cell wall morphology.

General information about the subject — on the page Tissue necrosis.

Sources8

Varieties of Napa cabbage mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.