Solanum is the most representative and largest genus of the family Solanaceae with numerous important crop species including potato, tomato and eggplant, etc. Wild species are crucial resources for elucidating interspecific relationships and breeding in this genus. Nightshades are various wild plant species belonging to the Solanum, consisting of many morphological variants collectively known as the Solanum nigrum complex. They are exploited for food, medicines, animal feed, and spiritual uses. They have especially proven useful in Solanum crop breeding. However, only a limited number of molecular cytogenetic studies have been reported, which has impeded comparative analyses that would allow a better understanding of Solanum genome evolution and facilitate breeding improvements. In this study, chromosomal level genome constitution and genome size were analyzed in three wild species of Solanum through triple-color fluorescence in situ hybridization (FISH) and flow cytometry. The chromosome number was 2n = 2x = 24 in S. americanum, 2n = 4x = 48 in S. villosum, and 2n = 6x = 72 in S. nigrum. Each pair of 5S and 45S rDNA signals was observed in diploid species; however, they proportionally increased with the ploidy level with two and three pairs in tetraploid and hexaploid species, respectively. Telomeric signals were detected in all the chromosome terminal regions of the three species. The diploid genotypes have an average genome size of 2.65 pg/2C, whereas the tetraploid and hexaploid species have approximately two- and three-fold larger genome sizes with 5.06 and 7.70 pg/2C, respectively. Our results suggest that the diploid species S. americanum and the tetraploid species S. villosum may be potential parents of the hexaploid species S. nigrum. This data will be helpful for future taxonomic, cytogenetic, phylogenetic, and evolutionary studies in Solanum as well as breeding improvement of this genus.

茄属是茄科中最具代表性和最大的属，拥有马铃薯、番茄、茄子等重要农作物品种。野生物种是阐明该属种间关系和育种的重要资源。茄属植物是属于茄科植物的各种野生植物物种，由许多形态变体组成，统称为龙葵复合体。它们被用于食品、药品、动物饲料和精神用途。事实证明它们在茄属作物育种中特别有用。然而，仅报道了有限数量的分子细胞遗传学研究，这阻碍了更好地了解Solanum的比较分析。基因组进化并促进育种改进。在本研究中，通过三色荧光原位杂交（FISH）和流式细胞术分析了三种野生茄属植物的染色体水平基因组构成和基因组大小。美洲S. americanum的染色体数目为2 n  = 2 x  = 24 ， S. villosum的染色体数目为2 n  = 4 x  = 48 ，S. nigrum的染色体数目为2 n  = 6 x  = 72。。在二倍体物种中观察到每对 5S 和 45S rDNA 信号；然而，它们随着倍性水平成比例地增加，四倍体和六倍体物种中分别有两对和三对。在这三个物种的所有染色体末端区域均检测到端粒信号。二倍体基因型的平均基因组大小为 2.65 pg/2C，而四倍体和六倍体物种的基因组大小大约是其两倍和三倍，分别为 5.06 和 7.70 pg/2C。我们的结果表明，二倍体物种S. americanum和四倍体物种S. villosum可能是六倍体物种S. nigrum的潜在亲本。这些数据将有助于茄属未来的分类学、细胞遗传学、系统发育和进化研究以及该属的育种改良。