Micropropagation of three ginger cultivars and the subsequent growth and rhizome yield assessment and phytochemical composition analysis

Farmers have turned to biotechnology techniques to produce ginger, due to disease issues. Micropropagation is a proven and effective means for mass production of disease-free plants. Our research focused on ginger cultivar specific reactions (from culture initiation to rhizome harvest) to plant growth regulators (PGRs) to determine if plant response to PGRs is cultivar specific. Ginger (Zingiber officinale Rosc.) cultivars studied were: Chinese White (CW), Hawaii Yellow (HY), and Khing Yai (KY) under benzylaminopurine (BA) versus kinetin (KT) treatments using MS basal medium to micropropagate ginger seedlings and subsequent growth and yield performance and phytochemical composition analysis. In vitro culture data were collected every month for number of buds and shoots (and shoot length) produced per initiating bud and shoot growth. Mature seedlings were subsequently transplanted in a greenhouse with a randomized complete block design (RCBD) with 4 replications, 18 plants per replication (Main Plot = Cultivar, Sub Plot = PGR) for a total of 72 pots/plants. Growth data included number of stems per seedling, stem length, and stem diameter. Rhizome yield data included number of pieces of rhizome per seedling, and rhizome weights (biological, edible, and total rhizome weights respectively). Phytochemical composition analysis of ginger rhizome/PGR treatment included average amount of 6-gingerol, 8-gingerol, 10-gingerol, 6-shogoal, 8-shogoal, and 10-shogoal. Data was analyzed using SAS OnDemand for Academics with PROC GLM at α=0.05 level of significance. As ginger tissue culture seedlings progressed in culture, KT was more suitable for multiplication of buds, BA more suitable for proliferation of shoots, and KT matured ginger tissue culture seedlings at a higher rate than BA. CW had the highest rhizome yield and least amount of biological roots in comparison to other cultivars. CW produced the least amount of 8-gingerol, 10-gingerol, 8-shogoal and 10-shogoal of all three cultivars and with no significant change between two PGR treatments. In comparison, HY produced the highest amount of 6-gingerol, 8-gingerol, 10-gingerol, 6-shogoal, and 8-shogoal, followed by KY and CW, when micropropagated with BA. KY produced the highest amount of 10-shogoal when micropropagated with BA and the highest amount of 6-gingerol, 6-shogoal, 8-shogoal, and 10-shogoal when micropropagated with KT.