The infrageneric delimitation of Momordica, a medicinally important genus of Cucurbitaceae, is ill-defined until date. Momordica chromosomes are extremely small and are difficult to stain and visualize because of the dense cytoplasmic background. We have conducted karyomorphometric analysis by EMA method in five Indian Momordica species, and the nuclear genome sizes were estimated by flow cytometry for the first time. The somatic chromosome numbers ranged from 2n = 18 to 56 in the species. We have resolved previously disputed chromosome numbers in M. cymbalaria and M. dioica as 2n = 18 (lowest) and 2n = 56, respectively. Chromosome counts in the other species were re-confirmed as 2n = 22 in M. charantia, 2n = 28 in M. cochinchinensis and 2n = 56 in M. subangulata. The largest genome size was recorded in M. cymbalaria (3.74 pg 2C-1), while the smallest size (0.72 pg 2C-1) was detected in M. charantia var. charantia. The nuclear genome sizes were analysed in comparison to chromosome numbers and total chromosome lengths of the species. Karyomorphometric indices showed comparable symmetric karyotypes in the species except in M. cymbalaria having tendency towards asymmetry. The UPGMA phenogram and principle component analysis based on nuclear DNA contents and karyomorphometric parameters demonstrated interspecies differences, intraspecific distinction within M. charantia varieties and highlighted distinction of M. cymbalaria. This study was further supported by the rDNA ITS sequence-based phylogenetic analysis which revealed the monophyletic origin of the Indian members of Momordica and clarified the intraspecies relationship among the studied members. As a whole, the study brought out new insights on species diversification within the genus Momordica in India and would benefit further studies on biosystematics and plant breeding programmes.

中文翻译：

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基于核形态学、核 DNA 含量和 rDNA ITS1-5.8S-ITS2 序列的印度苦瓜（葫芦科）系统发育分析

苦瓜是一种重要的葫芦科药用属，其属下划界迄今尚不明确。苦瓜染色体非常小，由于细胞质背景浓密，很难染色和观察。我们通过EMA方法对五种印度苦瓜进行了核形态计量学分析，并首次通过流式细胞术估计了核基因组大小。该物种的体细胞染色体数从2n = 18到56不等。我们已经将之前有争议的 M. cymbalaria 和 M. dioica 中的染色体数目分别解决为 2n = 18（最低）和 2n = 56。其他物种的染色体计数被重新确认为 2n = 22 在 M. charantia、2n = 28 在 M. cochinchinensis 和 2n = 56 在 M. subangulata。最大的基因组大小记录在 M. cymbalaria (3.74 pg 2C-1)，而最小的尺寸 (0.72 pg 2C-1) 在 M. charantia var. 中检测到。苦参。核基因组大小与染色体数量和物种的总染色体长度进行比较分析。核形态测量指数显示该物种具有可比的对称核型，但 M. cymbalaria 具有不对称趋势。基于核 DNA 含量和核形态计量学参数的 UPGMA 表型图和主成分分析证明了种间差异、苦瓜品种内的种内差异以及 M. cymbalaria 的突出差异。这项研究得到了基于 rDNA ITS 序列的系统发育分析的进一步支持，该分析揭示了印度苦瓜成员的单系起源，并阐明了研究成员之间的种内关系。总的来说，