DETERMINING GENETIC ORIGINS OF ABERRANT PROGENY FROM FACULTATIVE APOMICTIC KENTUCKY BLUEGRASS USING A COMBINATION OF FLOW-CYTOMETRY AND SILVER-STAINED RAPD MARKERS

Seeded plants that reproduce through facultative apomixis produce two types of progeny: (1) apomictic progeny genetically identical to the m aternal genotype, and (2) aberrant progeny genetically different from the maternal genotype. Aberrant progeny have at least nine different g enetic origins depending on gametic ploidy level and whether fertiliza tion was self, cross, or absent. Multiple genetic origins of aberrant progeny complicate the results of basic and applied genetic studies. D etermining the genetic origin of progeny plants using traditional tech niques, such as cytology, embryology, and segregational studies, is te chnically difficult in Kentucky bluegrass. We have found that two rela tively new techniques, flow cytometry and silver-stained RAPD (ssRAPD) markers, are powerful tools for rapidly determining the genetic origi ns of aberrant Kentucky bluegrass progeny. Our application of these te chniques demonstrate that (1) flow cytometry accurately distinguishes progeny ploidy levels, and (2) ssRAPD markers distinguish progeny resu lting from cross-fertilization. Therefore, a combination of flow cytom etry and ssRAPD data would be useful for most genetic studies of aberr ant individuals. Moreover, ssRAPDs were found to be of value for measu ring the loss of genetic markers from polyhaploids and quantifying the inheritance of parental genomes in polydiploid B(II) (n + n) and poly triploid B(III) (2n + n) hybrids. Quantifying shared ssRAPD markers ma y also be useful for determining genetic relatedness between varieties and germplasm sources.