Karyotype analysis of the dark-purple tea cultivar ‘Ziyan’

Tea plants (Camellia sinensis) are used to produce the most widely consumed beverage. ‘Ziyan’ is a new tea cultivar with dark purple young shoots at an altitude of approximate 1500 m in Sichuan province, China. There are abundant anthocyanins in ‘Ziyan’. In this research, we try to obtain cytological parameters on the dark-purple tea cultivar ‘Ziyan’. 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 max arm ratio was determined 2.50, relative length ranged from 3.56% to 5.39%. There are two types of relative length, including medium long (M2) and medium short (M1). In addition, the maximum centromeric index was measured in 49.02%, centromere type were metacentric (m) and submetacentric chromosomes (sm) chromosomes. Two satellites were observed at the tenth pair of chromosomes. Karyotype asymmetry index was 59.92%, and the karyotype formula was 2n=2x=30=22m (2SAT) +8sm. The karyotype characteristics was type 2B according to Stebbins’s classification criteria. The findings revealed its karyotypic characteristics of the dark-purple tea cultivar ‘Ziyan’ from the cytogenetic aspects.