Evaluation of genome size and phylogenetic relationships of the complex species.

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" complex" is a hypothetical group of species, which is supposed to be involved in the origin of modern sugarcane, and displays large genomes and complex chromosomal alterations. The utilization of restricted parents in breeding programs of modern cultivated sugarcane has resulted in a genetic blockage, which controlled its improvement because of the limited genetic diversity. The use of wild relatives is an effective way to broaden the genetic composition of cultivated sugarcane. Due to the infrequent characterization of genomes, the potential of wild relatives is diffused in improving the cultivated sugarcane. To characterize the genomes of the wild relatives, the genome size and phylogenetic relationships among eight species, including , , , , , , and were evaluated based on flow cytometry, genome surveys, K-mer analysis, chloroplast genome sequencing, and whole-genome SNPs analysis. We observed highly heterozygous genomes of , , and and the highly repetitive genome of . The genomes of , , , and were highly complex. Phylogenetic results of the two approaches were dissimilar, however, both indicate displayed closer relationships to and than other species of complex. was more closely related to than ; differ significantly from , and , but was relatively close to We proved the point of and should not be classified as one genus, and should be classified as the genus.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-022-03338-5.