Genetic variation and evolution of the alpine bamboos (Poaceae : Bambusoideae) using DNA sequence data

Difficulties in phylogenetic reconstruction are common within the woody bam boos due to their unique life cycles, a lack of morphological characters an d even an absence of molecular evidence. The genetic variability and popula tion structure of the bamboos are also poorly understood which impedes thei r exploitation via breeding. In this paper, ITS sequence data were used to examine the degree of genetic variation within the alpine bamboos and to ex plore their phylogeny. Twenty-three species representing three genera, Tham nocalamus, Fargesia and Yushania, of the alpine bamboos and one species of Ampelocalamus as an outgroup were studied. The results indicated that Thamn ocalamus spathiflorus var. crassinodus and the Fargesia spathacea clade for m the basal groups but bootstrap support was weak. Among the rest of the sp ecies, including species previously placed in Fargesia (plus Borinda) and Y ushania, the F. yunnanensis subclade and the F. communis subclade were reco gnized but internal support for such groups was again low. The result indic ated that, Fargesia and Yushania as delimited by morphological characters, are not monophyletic in the ITS phylogeny and require further resolution. W e revealed relatively high levels of genetic variability in the alpine bamb oos and showed that the ITS region could be used to improve generic delimit ation of the woody bamboos in general.