Karyotype analysis of Brassica juncea cv. Hong Kong Bamboo mustard

Brassica juncea is one of the important leaf vegetables which had important edible value, and was popular with consumers. Brassica juncea cv. Hong Kong Bamboo Mustard had characteristics of flesh crispy, tasted sweet and delicious, and had been widely cultivated in many places of China. In this research, we try to obtain cytological parameters on ’Hong Kong Bamboo Mustard’. Seven chromosomal parameters were measured and calculated: chromosome length, relative length, index of relative length, type of relative length, arm ratio, centromere index and centromere type. The experiment results showed that the maximum chromosome length was measured 4.76 µm and max arm ratio was determined 1.99, relative length ranged between 2.85% to 7.64%. There are four types of relative length, including long (L), medium long (M2), medium short (M1) and short (S) chromosomes. In addition, the maximum centromeric index was measured in 47.24%, centromere type were metacentric (m) and submetacentric chromosomes (sm) chromosomes. Karyotype asymmetry index was 60.58%, and the karyotype formula was 2n=36=22m (2SAT)+14sm. The karyotype characteristics was type 1B according to Stebbins’s classification criteria. The findings revealed its karyotypic characteristics of ’Hong Kong Bamboo Mustard’ from the cytogenetic aspects.