Plasmodiophora brassicae in Yunnan and its Resistant Sources in Chinese Cabbage

Abstract

The Williams differential system was employed for pathotype identification of 34 Plasmodiophora brassicaeroot samples collected from Yunnan Province and pathotypes 1, 2, 4, 10 and 14 were detected. Pathotype 4 was dominant with 70.59% of all the samples in Yunnan. The distribution of the P. brassicae pathotypes was mapped. Resistance to P. brassicae (clubroot disease) was investigated in 22 Chinese cabbage cultivars and it was found that the cultivar Shangpin had multiple resistances and was immune while Shangpin CR527 and Shangpin CR523 were resistant to P. brassicae. These cultivars can be used by farmers as sources of resistance to P. brassicae, to aid them in reducing disease in their crops. Seven known clubroot-resistant genes were detected in the 22 Chinese cabbage cultivars. CRa and CRb were found to be the most resistant to P. brassicae pathotype 4. Beisheng CR12 was resistant to pathotypes 1, 4, 10 and 14, but did not carry any known resistance genes, which indicated that unknown resistant genes were present. This study will lay the foundation for the control of clubroot disease and promote disease-resistant breeding of Chinese cabbage. © 2021 Friends Science Publishers