Plow cytometric analysis of ploidy in Rhododendron (subgenus Tsutsusi)

Ploidy level was determined for six species and 88 cultivars of the Rhodode ndron subgenus Tsutsusi, High-resolution flow cytometry of nuclear DNA was performed on macerated plant tissue. All plants analyzed were diploid (2n = 26) with the exception of 'Euratom, 'Euratom Orange', and 'Red Wing', whic h were triploid (3n = 39), and 'Casablanca Tetra', which was found to be a cytochimera: mixoploid (2n + 4n) in the LI and LII, but tetraploid in the L III. The described method has proven to be useful in screening a large popu lation of rhododendrons, Analysis of different organs and plant tissues was easily accomplished through flow cytometry, and has proven useful in deter mining the ploidy df different histogenic layers.