Cytological Study of <i>Begonia</i> Sect. <i>Diploclinium</i> (Begoniaceae)

Abstract

Previous chromosome information is restricted to 13 species in the Asian Begonia sect. Diploclinium.Here we present the first chromosome counts of three species, as well as confirmed their chromosome numbers of five species. Among three species investigated for the first time, the chromosome number of 2n=18 and 2n=32 are new counts in the section. Additionally, we provide the karyotypes of eight species for the first time. Among ca. 135 species in sect. Diploclinium, chromosome numbers of 16 species are available together with the present and previous reports. Among 16 species, they show diverse chromosome numbers with 2n=18, 22, 24, 26, 30, 32, 36, 46, and 54. B. wenshanensis with 2n=18 is the lowest chromosome number in the section and the third lowest chromosome number in Begonia. We suggest that B. coptidimontana with 2n=32 is tetraploid origin with the basic chromosome number of x=8. We discussed the chromosome evolution in Begonia sect. Diploclinium.

Cytological Study of <i>Begonia</i> Sections <i>Petermannia</i> and <i>Haagea</i> (Begoniaceae): Chromosome Evolution for 2<i>n</i>=30

“…Li & H. Ma in sect. Diploclinium (Kono et al 2021b). In this study, additional karyotype of 2n=30= 16m+ 14sm(st) 2sm is reported for two species of sect.…”

“…5a, b) as well as species with 2n=30= 12m+ 18sm(st) 2sm reported in sect. Diploclinium (Kono et al 2021b) and 2n=30= 8m+ 22sm(st) 2sm in sections Petermannia and Haagea. Therefore, in Asian Begonia, two sm-chromosomes in the respective chromosome complements are common to all species with 2n=30 in sections Baryandra, Coelocentrum, Diploclinium, Petermannia, and Haagea.…”

“…Therefore, in Asian Begonia, two sm-chromosomes in the respective chromosome complements are common to all species with 2n=30 in sections Baryandra, Coelocentrum, Diploclinium, Petermannia, and Haagea. Kono et al (2021b) proposed that in sect. Diploclinium 2n=30 is a tetraploid originating via chromosome fusion of two sm-chromosomes of 2n=32 and/or 2n=36.…”

“…Haagea. While 2n=30 has been reported for both sections Haagea and Petermannia, this number is also known in other Asian Begonia sections, including Baryandra (Kono et al 2021a), Coelocentrum (Kono et al 2020), Diploclinium (Kono et al 2021b), Jackia Doorenbos 1969, Doorenbos et al 1998), and Reichenheimia (Sharma and Bhattacharyya 1957, Legro and Doorenbos 1973, Nakata et al 2003. However, karyotypic analyses showed 2n=30= 8m+ 22sm(st) in sections Baryandra (Kono et al 2021a) and Coelocentrum (Kono et al 2020), and 2n=30= 12m+ 18sm(st) 2sm in sect.…”

“…However, karyotypic analyses showed 2n=30= 8m+ 22sm(st) in sections Baryandra (Kono et al 2021a) and Coelocentrum (Kono et al 2020), and 2n=30= 12m+ 18sm(st) 2sm in sect. Diploclinium (Kono et al 2021b). To better understand Asian Begonia species characterized by chromosome number 2n=30, this paper reports additional chromosome counts of sections Petermannia and Haagea and their karyotypes.…”