Studies on chromosome ploidy of Pyrus germplasm collection by flow cytometry

Many karyotypes of pear cultivars and Pyrus germplasm were observed by Giemsa staining during the last 30 years. Some triploid and tetraploid Pyrus germplasms were found and used to create novel polyploidy germplasms. The chromosome number of 400 Pyrus germplasms were identified by flow cytometry (FCM) in this study to help to understand their diversity in chromosome level and provide evidence about the study of system evolution or polyploid breeding. The results indicated that the chromosome numbers of known polyploid germplasms were the same as Giemsa staining and 15 new triploid germplasms were found. In total, a simple, rapid and efficient method of FCM suitable for Pyrus ploidy identification was optimized and could be generally used to identify Pyrus polyploid and polyploid F₁ seedlings.