Detection of chromosome ploidy level in Dactylis glomerata and Lolium multiflorum by flow cytometry

A practice of detecting chromosome ploidy levels in Dactylis glomerata and Lolium multiflorum by a flow cytometry method was reported; and aimed to discuss its application and reliability in forage polyploidy research. In order to investigate the chromosome ploidy levels of 4 D. glomerata germplasms (Wasemidori, PI316209, PI237602 and PI36880) and 3 L. multiflorum cultivars (Musashi, Tachimasari and Wasehope Ⅲ) by using the flow cytometry method, two known tetraploidy cultivars, including D. glomerata cv. Kitamidori and L. multiflorum cv. Mammoth B, were used as control materials. Their chromosome number in root tissue cells were double checked by the optical method and used to set a standard value in a flow cytometry. The results indicated that both of Wasemidori and PI316209 in D. glomerata were tetraploids, but PI237602 and PI36880 were diploids. For 3 tested L. multiflorum cultivars, Musashi was tetraploid, while Tachimasari and Wasehope Ⅲ were diploids. All chromosome ploidy levels of the tested cultivars or germplasms were confirmed to their known ploidy levels except of PI316209 in D. glomerata, which was a tetraploid instead of a diploid. The results provided a good reference to detect various chromosome levels in a same species by the flow cytomety method.