Karyotype Analysis of Buckwheat Using Atomic Force Microscopy

Abstract Karyotype analysis and classification of buckwheat chromosomes were performed without chemical banding or staining using atomic force microscopy (AFM).Fagopyrum esculentum(common buckwheat) andFagopyrum tartaricum(Tartarian buckwheat) chromosomes were isolated from root tissues using an enzymatic maceration technique and spread over a glass substrate. Air-dried chromosomes had a surface with ridges, and the height of common and tartary buckwheat were approximately 350 and 150 nm. Volumes of metaphase sets of buckwheat chromosomes were calculated using three-dimensional AFM measurements. Chromosomes were morphologically characterized by the size, volume, arm lengths, and ratios. The calculated volumes of theF. esculentumandF. tartaricumchromosomes were in the ranges of 1.08–2.09 μm³and 0.49–0.78 μm³, respectively. The parameters such as the relative arm length, centromere position, and the chromosome volumes measured using AFM provide accurate karyomorphological classification by avoiding the subjective inconsistencies in banding patterns of conventional methods. The karyotype evolutionary trend indicates thatF. esculentumis an ancient species compared toF. tartaricum. This is the first report of a cytological karyotype of buckwheat using AFM.