Cytoplasmic diversity in Brassica rapa L. investigated by mitochondrial markers

Brassica rapa L. is an important vegetable and oilseed crop. Cytoplasmic diversity of 36 B. rapa accessions was analyzed using the mitochondria-specific markers. Twelve representative materials including five additional Brassica species and one Eruca sativa Mill. were used as references. A modified multiplex PCR amplification using four pairs of primers was performed to test the mitochondrial types (mitotypes) of the tested materials. Ten accessions were detected with Cam-I mitotype which could amplify 500 and 800 bp bands, twenty-two accessions with Cam-II mitotype which could amplify 500, 800 and 906 bp bands, one accession with Pol mitotype. Interestingly, three B. rapa accessions were revealed with nap mitotype, two of them were local landraces in northern Shaanxi, the third one was a variety from Gansu province which was developed using one local landrace from Northern Shaanxi as female parent. The considerable cytoplasmic diversity in B. rapa provides useful information on studying the possible origin and evolution of B. rapa accessions, and conservation of the germplasm.