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

Abstract

Begonia sect. Baryandra is distributed mainly in the Philippines with a few species in Borneo and New Guinea. Previous chromosome information of sect. Baryandra has restricted to ca. 16 species and their karyotypes have never been investigated. Here we report the cytological investigations of 26 species of sect. Baryandra, including five karyotype analyses that are the first report in sect. Baryandra, 24 species were reported cytologically for the first time, and two species were re-examined. Incorporating previous and present studies, chromosome numbers of 40 of the 78 species in sect. Baryandra are now available. Except for some intraspecific variant counts of 2n=26 and 44, and a tetraploid number of 2n=56, 39 species have the chromosome number of either 2n=28 or 30. The karyotypic formula of the three investigated species is uniform as 2n=28=10m+18sm(st), and two as 2n=30=8m+22sm(st). Based on molecular phylogenetic relationships, ancestral state reconstruction suggests that 2n=30 is the most likely ancestral chromosome number of sect. Baryandra, with 2n=28 a derived number. Based on our and previous studies, the chromosome evolution in Begonia sect. Baryandra is discussed.

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

“…Although available cytological data of the section are still limited, a wide range of numbers (i.e., 2n=24-28, 28, 30, 36, 44, and 60) are reported. Among these numbers, 2n=28 (Legro and Doorenbos 1969) and 30 (Kono et al 2021a) are the most common numbers (Table 1), similar to sect. Baryandra (Kono et al 2021a) and sect.…”

“…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. Diploclinium (Kono et al 2021b).…”

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

“…Although cytological studies available for the section are still limited, they show a great range (2n=18, 22, 24, 26, 30, 32, 36, 46, and 54) (Sarkar 1989). Early studies by Legro and Doorenbos (1969, 1971, 1973 suggested that 2n=22, 28, and 38 are the most common chromosome numbers in Begonia, while our recent study indicated that 2n=30 is also one of the most common numbers in Asian Begonia (Kono et al 2021). Among the four most common chromosome numbers (i.e., 2n=22, 28, 30 and 38), 2n=22 was reported previously in three sections: Diploclinium (White et al 1946, Legro and Doorenbos 1969, Doorenbos et al 1998, Parvibegonia (Legro and Doorenbos 1971), and Platycentrum (Sharma and Blattacharyya 1961, Legro and Doorenbos 1969, 1971, Peng and Chen 1990, 1991, Doorenbos et al 1998, Peng and Chiang 2000, Peng and Sue 2000, Tian et al 2002, Oginuma and Peng 2002, Nakata et al 2003, 2005, 2007, Ye et al 2004, Li et al 2005a,b, Kono et al 2012, Ding et al 2014, Peng et al 2005c, 2015b, 2n=28 in three sections: Baryandra (Nakamura et al 2013, 2015, Peng et al 2017b, Kono et al 2021, Petermannia (Piton 1962), and Reichenheimia (Li et al 2005a), 2n=30 in seven sections: Baryandra (Hugh...…”

“…In Asian Begonia, karyotypes have only been reported in four sections, i.e., sect. Baryandra (Kono et al 2021), Coelocentrum (Kono et al 2020), Diploclinium (Oginuma and Peng 2002), and Platycentrum (Oginuma and Peng 2002, Peng et al 2014c, 2015c. In sect.…”

“…With the addition of numerous novelties (e.g., Peng et al 2006, 2014a, 2017a, Phuttai et al 2014 and the reduction of even more species to the recircumscribed sect. Baryandra (Rubite et al 2013, Kono et al 2021 and sect. Coelocentrum (Chung et al 2014, Moonlight et al (2018) recognized a paraphyletic sect.…”