Sports and hybrids of triploid Hosta 'Sum and Substance' reveal chromosome losses and gains in all three apical layers

Abstract

Ploidy distributions in L1, L2, and L3 apical or meristematic layers of 56 different plants (79 accessions) from vegetative and sexual progeny of the triploid Hosta 'Sum and Substance' were determined. Nuclear DNA contents (2C) of each apical layer were measured by flow cytometry with propidium iodide, and inferred ploidies are calculated. During tissue culture, the triploid (L1-L2-L3 = 3-3-3) Hosta 'Sum and Substance' exhibited chromosome losses resulting in somaclonal variants such as DNA aneuploids (e. g., 2.7-2.7-2.7) and aneuploidy chimeras (e. g., 3-2.7-2.7). Most interestingly, some chimeras exhibited even an increase in genome size as in plants with 3.5-3-3 configuration. Hybrids of H. 'Sum and Substance' show only losses of nuclear DNA compared with the original triploid. This gives rise to fully aneuploid plants and no chimeras. The measurements of Hosta 'Sum and Substance' lineages of sports and hybrids indicate that chromosome losses or gains are an important source of new cultivars. The complexity of chromosomal distribution in derivatives from the triploid Hosta 'Sum and Substance' is discussed. © 2012 The Author(s).