Cytogenetic characterization of Tropaeolum pentaphyllum Lam

Abstract The species Tropaeolum pentaphyllum Lam. (batata-crem or crem) is of great economic and medicinal importance. For being an endangered species, the knowledge of its genetic variability is necessary. Considering the lack of cytological studies on this species, this work describes the chromosome numbers, the meiotic behavior, the meiotic index, and the viability of the pollen grains of three populations of T. pentaphyllumm from Rio Grande do Sul, Brazil. The three populations presented 2n = 28 chromosomes. Meiotic behavior was regular, with low abnormality frequency (<1%), which culminated in IMx> 90% in the three accessions. This meiotic stability resulted in high production of viable pollen grains, which will favor the use of these accessions in selection programs for commercial purposes, conservation and sustainable use.

摘要 五叶旱金莲（Tropaeolum pentaphyllum Lam.，俗称batata-crem或crem）具有重要的经济与药用价值。作为濒危物种，明晰其遗传变异特征至关重要。鉴于当前该物种相关细胞学研究的匮乏，本研究针对巴西南里奥格兰德州的3个五叶旱金莲种群，系统描述了其染色体数目、减数分裂行为、减数分裂指数（meiotic index）及花粉活力。结果显示，3个种群的染色体数目均为2n=28；减数分裂行为规整，异常频率极低（<1%），使得3个种质的减数分裂指数均超过90%。这种减数分裂稳定性促成了大量高活力花粉的产生，将有利于这些种质应用于商业化选育、物种保护及可持续利用项目。