Cytogenetics Study of Four Edible and Ornamental Zingiber Species (Zingiberaceae) from Thailand

A cytological study was carried out on four Zingiber species from Thailand, namely, Z. chrysostachys, Z. isanense, Z. junceum, and Z. niveum, which are edible and beautiful ornamental plants. They all have somatic chromosomal numbers of 2n = 22. This research contributes to karyological knowledge regarding this species. The somatic chromosomal counts of Z. niveum and Z. isanense are reported for the first time, as are the NFs of all species, which were all discovered to be 44. All four edible and ornamental species had their karyotypes: 16m + 6sm for Z. chrysostachys, 4m + 18sm for Z. isanense, 12m + 10sm for Z. junceum, and 14m + 4sm + 4st for Z. niveum. The dominant characteristics of these four Zingiber species are as follows: Z. chrysostachys has yellow bracts, pale yellow flowers, and a red labellum with white dots; Z. isanensis has red-brown bracts, white flowers, and a white labellum; Z. junceum has green bracts, yellow flowers, and a yellow labellum; and Z. niveum has white bracts, yellow flowers, and a yellow labellum. Additionally, principal component analysis (PCA) of the karyotype formula was used to divide the four Zingiber species into two groups via various points using the chromosome indexes (CIs): Z. niveum (D) with Z. chrysostachys (A), and Z. junceum (C) with Z. isanensis (B). This finding implies that, while being in the same stage, the CIs of these four Zingiber species can be used to distinguish them, revealing their resemblance at unique stages and close relationship. Accordingly, the chromosomal structure, karyotype formulae, and CIs can be used to distinguish these four edibles and ornamental Zingiber species from Thailand.