Ploidy variation of progenies from intra- and inter-ploidy crosses with regard to trisomic production in asparagus (Asparagus officinalis L.)

Ploidy variation within progenies from intra- and inter-ploidy crosses of asparagus were determined in this study. The DNA content of most reduced microspores was half that of somatic cells in diploid, triploid and tetraploid plants as determined by flow cytometry. Many viable seeds were obtained from various 2x x 2x and 2x x 3x intra- and inter-ploidy crosses. Nuclear DNA contents of these progenies from reciprocal crosses between diploids and triploids were similar to those expected of diploids, but with a wider range: hyper- and hypo-diploids including trisomics seem to be involved in the progenies. Indeed, the number of chromosomes in the progenies of 2x x 3x crosses ranged from 18 to 23. Based on frequencies of viable seeds and trisomic phenotypic appearance, it was concluded that the 2x x 3x cross was most efficient for obtaining trisomic plants in Asparagus officinalis.