Karyotype polymorphism of GC-rich constitutive heterochromatin in Capsicum L. pepper accessions

Abstract Capsicum is represented by peppers and sweet peppers and comprises a group with remarkable genetic variability. Different cultivated Capsicum peppers of Brazil were evaluated by using CMA3 and DAPI specific fluorochromes. There was high polymorphism of highly GC-rich CMA heterochromatic bands among the analyzed species, ranging from six (BAGC 114; C. annuum) to 26 blocks (BAGC 81; C. baccatum). Heterochromatin percentage ranged from 3.14% (BAGC 114; C. annuum) to 8.72% (BAGC 81; C. baccatum), corroborating the variation in the number of heterochromatic bands, particularly those distributed in the terminal and subterminal regions of the chromosomes. The information reported in this paper supports the cytogenetic characterization of the domesticated peppers accessions belonging to the Capsicum Germplasm Active Bank of the Federal University of Piauí (BAGC-UFPI). Moreover, the present data helped to better understand the karyotype features of peppers and provide additional information that could contribute to the improvement and maintenance of Capsicum genetic breeding programs.摘要：辣椒属（Capsicum）以普通辣椒与甜椒为代表，是一类具有显著遗传变异的植物类群。本研究采用特异性荧光染料色霉素A3（CMA3）与4',6-二脒基-2-苯基吲哚（DAPI），对巴西的不同栽培辣椒属种质进行了细胞遗传学分析。在所分析的物种中，富含GC碱基的CMA异染色质带呈现出较高的多态性，其数量范围为6个条带（BAGC 114；一年生辣椒C. annuum）至26个条带（BAGC 81；灌木辣椒C. baccatum）。异染色质占染色体总长度的比例范围为3.14%（BAGC 114；一年生辣椒C. annuum）至8.72%（BAGC 81；灌木辣椒C. baccatum），这一结果与异染色质带数量的变异情况相符，尤其是分布于染色体末端和亚末端区域的异染色质带。本文所报道的研究结果，可为皮奥伊联邦大学辣椒属种质资源活性库（BAGC-UFPI）所收录的栽培辣椒种质的细胞遗传学鉴定提供支撑。此外，本研究数据有助于进一步明晰辣椒的核型特征，并可为辣椒属遗传育种项目的优化与维持提供额外的参考依据。