Karyotype analysis of Nainaiqingcai mustard

Brassica juncea cv. Nainaiqingcai belongs to the mustard vegetables of the cruciferous family. It usually takes the leaves and petioles as the edible parts, and pickled pickle or fresh vegetable as the main way of eating, and occupies an important position in the local agricultural product market. In this research, seven chromosome parameters: chromosome length, relative length index, relative length, arm ratio, centromere index, and type of centromere type were measured. The experiment results showed that the maximum chromosome length was measured 3.60 µm and max arm ratio was determined 1.46, relative length ranged between 3.68% to 7.68%. There are including long (L), medium long (M2), medium short (M1) and short (S) chromosomes four types of relative length. In addition, the maximum centromeric index was measured in 45.66%, centromere type were metacentric (m) chromosomes and submetacentric chromosomes (sm) and the karyotype formula was 2n=36=30m+6sm. Karyotype asymmetry index was 59.631%. The karyotype characteristics was type 2B according to Stebbins’s classification criteria. According to the above information, we can drawn a conclusion that ’Nainaiqingcai’ is a relatively primitive mustard variety. In this research, the karyotypic characteristics of Nainaiqingcai mustard were revealed from the point of view of cytogenetics.