Plant Growth Analysis of Costus spectabilis and RAPD Marker Application to Identify Genetic Diversity among Four Selected Costus Species

The Costaceae family is distinguished by sheathing leaf bases that completely envelop the plant. However, limited publication is obtained from Costus spectabilis, a spectacular plant, unlike the other Costus species. It represents one of the symbols of Nigeria’s coat of arms. They are rich in phytochemicals as they possess therapeutic properties. Hence, this study aimed to evaluate the growth analysis of C. spectabilis and identify the genetic diversity among the four selected Costus species using the Random Amplified Polymorphic DNA (RAPD) markers. C. spectabilis was planted in 20 pots containing five different soil types. The plants were analysed for growth parameters which include leaf area index and duration, specific leaf area, and leaf area ratio. Collected data were calculated for analysis of variance and post hoc test at p<0.05. The results of study showed that sandy soil gives the best overall growth performance in all of the growth parameters in C. spectabilis. A total of 4 RAPD primers used in this study generated 52 bands, of which 40 bands were polymorphic with more than 2.25 loci per primer. The similarity values varied ranging from 0.44 to 0.71. Although the morphological differences among the four studied Costus species were apparent, the use of RAPD markers revealed a unique variety in Cheilocostus speciosus with a high percentage of polymorphism, which could be a very good reason for its being exploited for pharmaceutical purposes