Documented chromosome number determinations in some Physaria species (Brassicaceae)

Abstract

The determination of the chromosome numbers of species of Physaria (Brassicaceae) are of interest as part of a breeding program to develop new industrial oilseeds and to further our knowledge of the genus in general. Polyploid plants could be useful in generating novel and improved breeding populations. We report 47 meiotic chromosome number determinations for 19 species of Physaria. The first chromosome number is reported for P. kingii subsp. kaibabensis as 2n = 5 II, and the first report of polyploidy in Physaria kingii susbsp. latifolia with a tetraploid determination of 2n = 10 II. A determination of 2n = 23 II is reported for Physaria mendocina, which was previously reported as 2n = ca. 50, which results in a new base number for the genus of x = 23.